OBJECTIVE:The aortic isthmus (AoI) blood flow has a characteristic shape with a small end-systolic notch observed during the third trimester of pregnancy. However, what causes the appearance of this notch is not fully understood. We used a lumped model of the fetal circulation to study the possible factors causing the end-systolic notch and the changes of AoI flow through gestation. METHODS:A validation of the model was performed by fitting patient-specific data from two normal fetuses. Then, different parametric analyses were performed to evaluate the major determinants of the appearance of the end-systolic notch. The changes in the AoI flow profile through gestation were assessed. RESULTS:Our model allows to simulate the AoI waveform. The delay in the onset of ejection together with the longer ejection duration of the right ventricle are the most relevant factors in the origin of the notch. It appears around 25 weeks of gestation and becomes more pronounced with advancing gestation. DISCUSSION:We demonstrated that the end-systolic notch on the AoI flow occurs mainly as a result of a delayed and longer ejection of the right ventricle. Our findings improve the understanding of hemodynamic changes in the fetal circulation and the interpretation of clinical imaging.

OBJECTIVE:To investigate the potential value of cerebroplacental ratio (CPR) at 30-34 weeks' gestation in the prediction of adverse perinatal outcome. METHODS:This was a screening study in 30 780 singleton pregnancies at 30-34 weeks' gestation. Umbilical artery (UA) and fetal middle cerebral artery (MCA) pulsatility index (PI) were measured and the values were converted to multiples of the median (MoM) after adjustment from variables in maternal characteristics and medical history that affect the measurements. CPR was calculated by dividing MCA-PI MoM by UA-PI MoM. Multivariable logistic regression analysis was used to determine if measuring CPR improved the prediction of adverse perinatal outcome provided by screening with maternal characteristics, medical history and obstetric factors. The detection rate (DR) and false-positive rate (FPR) of screening by CPR were estimated for stillbirth, Cesarean section for fetal distress, umbilical arterial cord blood pH ≤ 7.0, umbilical venous cord blood pH ≤ 7.1, 5-min Apgar score < 7 and admission to the neonatal unit (NNU) and neonatal intensive care unit (NICU). RESULTS:There was a significant association between CPR and birth-weight Z-score. In addition to maternal characteristics, medical history and obstetric factors, measuring CPR provided a significant contribution to the prediction of arterial cord blood pH ≤ 7.0, venous cord blood pH ≤ 7.1 and admission to NNU. The performance of CPR in screening for each adverse outcome was poor, with DR of 5-11% and a FPR of about 5%. In the small subgroup of the population delivering within 2 weeks following assessment, the DR improved to 20-50%, but with a simultaneous increase in FPR to 10-23%. CONCLUSION:The performance of CPR in routine screening for adverse perinatal outcome at 30-34 weeks' gestation is poor.

OBJECTIVE:To determine the effects of increased ultrasound probe pressure and maternal Valsalva maneuver (VM) on the middle cerebral artery (MCA) Doppler ultrasonography in fetuses. METHODS:A total of 120 healthy pregnant women in second and third trimesters were enrolled in the study. MCA blood flow was measured by pulsed Doppler sonography in 60 fetuses (24 and 40 weeks' gestation) before and after the application of increased ultrasound probe pressure. In the other 60 fetuses (32 and 36 weeks' gestation), sonography was performed before and after maternal VM. Statistical analysis was performed by paired t-test. RESULTS:The pressure induced by the ultrasound probe induced a significant increase in the pulsatility index (PI), resistance index (RI), and peak systolic velocity (PSV); however, a significant decrease was found in the end-diastolic velocity (EDV) (p < 0.05). No statistically significant difference was found in the mean flow velocity (MFV). Moreover, maternal VM did not have any effect on the PI, RI, EDV, or MFV. CONCLUSION:Fetal MCA Doppler assessment is affected by increased probe pressure but not by maternal VM. Thus, the application of the MCA Doppler sonography should be undertaken in the head of fetuses without any probe pressure and without maternal VM.

OBJECTIVES:To determine whether color Doppler sonography increases the detection of pregnancies at risk for adverse outcomes. METHODS:Participants admitted to labor and delivery with the anticipation of a vaginal delivery underwent measurements of amniotic fluid volume (AFV) using amniotic fluid index (AFI) and single deepest pocket (SDP) techniques by grayscale followed by color Doppler sonography. Oligohydramnios was defined as an AFI of less than 5 cm or an SDP of less than 2 cm. Intrapartum and perinatal outcomes were compared between participants with a diagnosis of a low AFV by grayscale and color Doppler sonography. RESULTS:Over 42 months, 428 women were enrolled in the study. Color Doppler sonography resulted in lower AFV estimates (mean ± SD by the AFI, 10.7 ± 3.7 cm by grayscale sonography and 8.6 ± 3.6cm by color Doppler sonography; P < .0001). For the SDP, the mean AFVs were 4.6 ± 2.0 cm by grayscale sonography and 3.4 ± 1.4 cm by color Doppler sonography (P < .0001). The level of agreement between grayscale and color Doppler sonography in estimating the AFV was fair, with κ = 0.32 for the AFI and 0.28 for the SDP. Outcome measures of AFVs classified as low based on color Doppler sonography (normal by grayscale sonography) and those classified as low by grayscale sonography (low by color Doppler sonography) were compared. There was no difference in composite perinatal complications, mode of delivery, or composite neonatal complications. CONCLUSIONS:The use of color Doppler sonography leads to the overdiagnosis of low AFVs and does not appear to increase the detection of pregnancies destined for adverse intrapartum or perinatal outcomes.

One of the most important applications of Doppler ultrasonography in obstetrics is the detection of fetal anemia in pregnancies complicated by either red-cell alloimmunization or by other causes of fetal anemia. Doppler of the umbilical artery also has prognostic value in pregnancies affected by twin-twin transfusion syndrome undergoing in-utero intervention. Another potential major application is the use of Doppler ultrasound in the management of intrauterine-growth-restricted fetuses. At the present time, there is no single test that appears superior to the other available tests for timing the delivery of the growth-restricted fetus. Therefore, the decision to deliver a fetus, especially at <32 weeks, remains mostly based on empirical management. Doppler may provide a more reliable and systematic basis for timing these deliveries. This review emphasizes the three following concepts: (a) normal and abnormal Doppler of the umbilical artery, middle cerebral artery, mitral and tricuspid valves, umbilical vein, and ductus venosus; (b) some clinical applications of Doppler sonography in obstetrics; and (c) potential future research of Doppler in obstetrics.

OBJECTIVE:The purpose of this study was to examine the presence and frequency of antegrade late diastolic arterial blood flow (ALDAF) in the fetus and to determine its contribution to cardiac output. STUDY DESIGN:We evaluated the presence of ALDAF in 457 fetal and 21 postnatal echocardiograms. The timing of ALDAF to the ventricular systolic Doppler recording (ALDAF-V) was compared with the mechanical atrioventricular interval and, in neonates, the electrical PR interval. Velocity time integrals of ALDAF and the ventricular systolic Doppler signals were measured, and the percent contribution of ALDAF was calculated. RESULTS:ALDAF was observed in 365 of 457 studies and included all <11 weeks' gestations. Strong correlation between ALDAF-V, atrioventricular interval, and electrical PR interval suggests that ALDAF coincides with atrial contraction. ALDAF contributed substantially to cardiac output in early gestation with later decline. CONCLUSION:ALDAF results from atrial contraction. Increasing gestational age results in less ALDAF, and reduced ALDAF contribution to cardiac output likely due to improved diastolic function.

OBJECTIVE:To compare neonatal outcome and placental pathology in cases of small for gestational age (SGA) according to umbilical artery (UA) Doppler flow. STUDY DESIGN:Pregnancy and placental reports of SGA neonates (birth-weight <10th), born between 2008 and 2017 were compared between cases with normal and abnormal UA Doppler indices. Placental lesions were classified to malperfusion lesions and inflammatory responses. RESULTS:The abnormal Doppler group (n = 66) delivered at an earlier gestational age, compared to the normal Doppler group (n = 92). Placentas from the abnormal Doppler group were characterized by a higher rate of maternal malperfusion lesions, while placentas from the normal Doppler group exhibited a higher rate of chronic villitis. Neonatal outcome was independently associated with abnormal Doppler, gestational age and birth weight <5th percentile. CONCLUSION:SGA may involve a vascular mechanism, associated with abnormal Doppler flow and placental malperfusion, and an inflammatory mechanism, with normal Doppler flow and chronic villitis.

OBJECTIVES:To develop an objective image-scoring system for pulsed-wave Doppler measurement of maternal uterine and fetal umbilical arteries, and evaluate how this compares with subjective assessment. METHODS:As an extension to the INTERGROWTH-21 Project, we developed a scoring system based on six predefined criteria for uterine and umbilical artery pulsed-wave Doppler measurements. Objective evaluation using the scoring system was compared with subjective assessment which consisted of classifying an image as simply acceptable or unacceptable. Based on sample size estimation, a total of 120 umbilical and uterine artery Doppler images were selected randomly from the INTERGROWTH-21 image database. Two independent reviewers evaluated all images in a blinded fashion, both subjectively and using the six-point scoring system. Percentage agreement and kappa statistic were compared between the two methods. RESULTS:The overall agreement between reviewers was higher for objective assessment using the scoring system (agreement, 85%; adjusted kappa, 0.70) than for subjective assessment (agreement, 70%; adjusted kappa, 0.47). For the six components of the scoring system, the level of agreement (adjusted kappa) was 0.97 for anatomical site, 0.88 for sweep speed, 0.77 for magnification, 0.68 for velocity scale, 0.68 for image clarity and 0.65 for angle of insonation. CONCLUSION:In quality assessment of umbilical and uterine artery pulsed-wave Doppler measurements, our proposed objective six-point image-scoring system is associated with greater reproducibility than is subjective assessment. We recommend this as the preferred method for quality control, auditing and teaching. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

PURPOSE: The human aorta stores strain energy in the distended wall during systole through the extracellular matrix of the tunica media that could be influenced by blood pressure, flow, or increased peripheral resistance. In intrauterine growth restriction (IUGR) fetuses, the increased aorta intima media thickness (aIMT) could reflect a different extracellular matrix composition and, therefore, functionality. The aim of this study was to analyze the resistance to flow in the fetal descending aorta and its relation to aIMT and systolic and diastolic fetal abdominal aorta diameters in IUGR fetuses and controls. MATERIALS AND METHODS:This is a prospective case control study of single pregnancies collected at a tertiary center for feto-maternal medicine in Northeast Italy. An IUGR group as cases and a group of fetuses appropriate for gestational age (AGA) as controls were included. RESULTS: We found a greater PI of the fetal abdominal aorta in the IUGR group (1.82) than in the AGA group (1.21) (p < 0.05). The change between the systolic and diastolic fetal abdominal aorta diameters was significantly greater in IUGR fetuses (0.10 mm (IQR 0.07 - 0.28)) than in the AGA group (0.04 mm (0.03 - 0.05)) (p < 0.05). In the IUGR group aIMT was significantly correlated with peak systolic velocity (PSV) and systolic-diastolic aorta diameter change, while these two correlations were not found in the control group. CONCLUSION: The change between the systolic and diastolic fetal abdominal aorta diameters in IUGR cases during the early third trimester of pregnancy was significantly increased and aIMT in the IUGR group was significantly correlated to systolic-diastolic diameter change and PSV, probably reflecting aortic wall adaptation to blood flow changes in IUGR fetuses.

OBJECTIVE:The aim of the present cross-sectional prospective study was to establish Doppler reference ranges for blood flow velocity waveforms (V max, V mean and V min) and resistance indices (PI, RI) of the fetal pulmonary arteries using the new pulsed-wave color advanced dynamic flow (ADF) Doppler technique. METHOD:Data were collected in 206 low-risk pregnancies at 18-41 weeks of gestation. The measurements were obtained in the proximal pulmonary artery near the first bifurcation in the absence of fetal body or breathing movements. RESULTS:The pulsatility index (PI) in the pulmonary artery showed mean increases of 2.43-3.59 between gestational weeks 18 and 42. A similar pattern was observed for the resistance index (RI) with increases of 0.79-0.90. Increases in systolic (V max), mean (V mean) and end diastolic (V min) blood flow velocities of 36.0-63.3, 10.8-19.9 and 5.71-7.53 cm/s, respectively, were noted during the observation interval. CONCLUSIONS:The ranges for blood flow velocities and impedance indices in the fetal pulmonary artery calculated by the authors may serve as reference values to help distinguish a normal patient population from patients carrying fetuses at high risk for neonatal lung disease in antenatal examinations.

PURPOSE: Myocardial function (MF) of the systemic right ventricle (RV) influences the postnatal course of neonates with hypoplastic left heart syndrome (HLHS). Our study examines whether the presence of endocardial fibroelastosis of the left ventricle (LV EFE) influences MF of the RV in HLHS fetuses. MATERIALS AND METHODS: A prospective study was conducted including 10 controls (group 1), 10 HLHS fetuses with (group 2) and 10 without LV EFE (group 3) - all matched for gestational age. M-mode was used to assess tricuspid plane systolic excursion (TAPSE) and the shortening fraction (SF). PW-Doppler-derived and PW-TDI-derived velocities were assessed. E/A, E/e', e'/a' ratios and the myocardial performance index (mpi') were calculated. RESULTS: The examination of MF revealed significantly lower s' velocities (p < 0.05) and higher values for SF in group 2 compared to group 3. e'/a' ratio, et' (ejection time), E wave velocity, E/e' and SF showed significantly higher values in group 2 compared to group 1. In group 2 a' velocity increased significantly over gestational age. In group 3 but not in group 2, TAPSE increased during gestation. CONCLUSION: These significant differences in MF between the groups might lend support to the notion of negative ventricular-ventricular interaction in the case of HLHS with LV EFE possibly influencing surgical outcomes.

PURPOSE:To asses the occurrence of discrepancies between the Doppler waveforms of the left and right umbilical arteries in their paravesical part in fetuses with absent or reversed end-diastolic flow in the free-floating umbilical cord. METHODS:This prospective observational study included pregnant women with fetal growth restriction or twin-to-twin transfusion syndrome. Umbilical arterial Doppler waveforms were obtained from both umbilical arteries in their intra-abdominal paravesical part. Doppler findings were recorded as present end-diastolic flow (PEDF)/absent end-diastolic flow (AEDF); AEDF/AEDF; AEDF/reversed end-diastolic flow (REDF); or REDF/REDF pattern. RESULTS:There were 49 fetuses with AEDF or REDF at the free-floating umbilical cord. Of these, 20 (40.8%) had a discrepancy in Doppler waveforms between the two umbilical arteries, with 14 (28.6%) showing PEDF/AEDF, 17 (34.7%) AEDF/AEDF, 6 (12.2%) AEDF/REDF, and 12 (24.5%) REDF/REDF pattern. CONCLUSION:Doppler waveforms showed discrepancies between the two umbilical arteries in 40.8% of pregnant women with AEDF or REDF in the free-floating umbilical cord. The presence of end-diastolic flow in one umbilical artery cannot exclude the possibility of AEDF in the other.

OBJECTIVE:To determine if there are changes in maternal uterine blood flow, fetal brain blood flow, fetal heart rate variability, and umbilical blood flow between morning (AM) and afternoon (PM) in healthy, uncomplicated pregnancies. STUDY DESIGN:In this prospective study, 68 uncomplicated singleton pregnancies (mean 35 + 0.7 weeks gestation) underwent a standard observational protocol at both 08:00 (AM) and 13:30 (PM) of the same day. This protocol included Doppler measurements of uterine, umbilical, and fetal middle cerebral artery (MCA) volume flow parameters (flow, HR, peak systolic velocity [PSV], PI, and RI) followed by computerized cardiotocography. Standard descriptive statistics, χ and t tests were used where appropriate. P < .05 was considered significant. RESULTS:A significant increase in MCA flow and MCA PSV was observed in the PM compared to the AM. This was accompanied by a fall in MCA resistance. Higher umbilical artery resistance indices were also observed in the PM compared to AM. In contrast, fetal heart rate characteristics, maternal uterine artery Doppler flow and resistance indices did not vary significantly between the AM and PM. CONCLUSION:In normal pregnancies, variations in fetal cerebral and umbilical blood flow parameters were observed between AM and PM independent of other fetal movements or baseline fetal heart rate. In contrast, uterine flow parameters remained stable across the day. These findings may have implications for the use of serial Doppler parameters used to guide clinical management in high-risk pregnancies.

INTRODUCTION:Recent studies have reported variations of up to 30% between different ultrasound machines for tissue Doppler imaging (TDI), a problem that can significantly impact clinical diagnosis, patient management and research studies. The objective of this study was to assess repeatability and agreement between fetal myocardial peak velocities evaluated by TDI with two different ultrasound systems. MATERIALS AND METHODS:Systolic (S'), early (E') and late (A') diastolic myocardial peak velocities at mitral and tricuspid annuli as well as at the basal septum were evaluated by spectral TDI in 150 fetuses using two different ultrasound systems: Siemens Antares (Siemens Medical Systems, Malvern, Pa., USA) and Vivid Q (General Electric Healthcare, Horten, Norway). A method comparison study was performed, calculating intraclass correlation coefficients (ICC), and agreement was assessed by Bland-Altman plots. RESULTS:Annular peak velocities showed lower values when measured by Vivid Q compared to values measured by Siemens Antares. ICC ranged from 0.07 (septal S') to 0.33 (right A'), showing very poor repeatability for clinical application. Agreement between the two systems was also poor, with high coefficients of variation for all measurements. CONCLUSIONS:Fetal annular peak velocities obtained with different ultrasound systems are not directly comparable. This is consistent with previous data in adults and warrants the need of system-specific reference values, suggesting that the same ultrasound machine should be used for longitudinal follow-up.

OBJECTIVE:The outcome of patients with hypoplastic left heart syndrome (HLHS) is influenced by right ventricular function. This study aimed to investigate whether differences in right ventricular function of fetuses with HLHS are present during gestation. METHODS:This was a prospective study comprising 14 fetuses with HLHS (28 measurements obtained in total) and 28 normal control fetuses (31 measurements obtained in total). The two groups were matched for gestational age. Ultrasound M-mode was used to assess displacement of the tricuspid annulus. Spectral Doppler and myocardial tissue Doppler-derived inflow and outflow velocities were assessed. Tricuspid valve peak early wave to peak active wave (E/A) ratio, the early wave to early diastolic annular relaxation velocity (E/E') ratio and the tissue Doppler-derived myocardial performance index (MPI') were calculated. RESULTS:E-wave velocity was significantly higher in fetuses with HLHS than in control fetuses (mean, 40.14 cm/s vs 35.47 cm/s; P < 0.05, respectively), and A-wave velocity in fetuses with HLHS showed a tendency for higher values in the right ventricle compared with normal control fetuses, but this did not reach statistical significance (61.16 cm/s vs 54.64 cm/s; P = 0.08). The E/A ratio increased during gestation in controls, but this increase was not seen in HLHS fetuses. Peak annular velocity during atrial contraction (A') and the E/E' ratio were significantly lower in controls than in HLHS fetuses: 9.50 cm/s vs 10.39 cm/s (P < 0.05) and 5.77 vs 7.37 (P < 0.05), respectively. There were no differences for right-ventricular MPI' or tricuspid annular plane systolic excursion between HLHS fetuses and controls. CONCLUSION:The results of this study show that altered right ventricular function in HLHS infants may develop antenatally. It is hoped that confirmation of these findings using Doppler-independent techniques will lead to further exploration of ventricular function in HLHS fetuses. Consequently, parental counseling and postnatal management strategies could be influenced.

OBJECTIVES:The purpose of this study was to compare Doppler velocimetric indices between the left and right intra-abdominal umbilical arteries in normally grown and growth-restricted fetuses. METHODS:In this cross-sectional study, Doppler indices of the intra-abdominal segment of the left and right umbilical arteries were measured lateral to the fetal bladder. Measurements, including the systolic to diastolic ratio and pulsatility index, were obtained from both anatomic locations. The Student t test was used to make comparisons. RESULTS:Differences between left and right Doppler indices were noted in 98% of patients, and these differences were greater than 20% in at least one-third. Overall, the left umbilical artery had a higher systolic to diastolic ratio (P = .025) and pulsatility index (P = .007) than the right umbilical artery. CONCLUSIONS:The laterality of the umbilical artery, whether on the left or right side of the fetus, influences important Doppler blood flow parameters.

INTRODUCTION:Intrauterine growth restriction (IUGR) is a major clinical issue for pregnant women. The purpose of this study was to evaluate color Doppler indices of the proximal and distal parts of the middle cerebral artery (MCA) of the fetus. METHODS:In this cross-sectional study, 350 pregnant patients, with gestation age of 32-40 who were suspected to have intrauterine growth restriction, participated. The patients were referred for color Doppler sonography at the Imam Reza Hospital (Kermanshah, Iran) from May 2011 to September 2012. The following indices were measured for the proximal and distal part of the MCA: pulsatility index (PI), resistive index (RI), fetal heart rate (FHR), systolic to diastolic (S/D) ratio, and peak systolic velocity (PSV). The data were analyzed applying Tukey's-test, Paired-Samples t-test, and simple linear regression analysis using SPSS 19. RESULTS:Average age of the mother, the frequency of pregnancy, and fetus gestational age were 27.79±0.17 years, 2.09±1.3, and 34.19±2.52 weeks, respectively. For gestation age of <36weeks, all Doppler indices of the distal part of the fetus MCA were significantly different from those of proximal part (p<0.05). Comparing indices of gestation age <36 weeks with those of >36 weeks, significant difference was found between the Doppler indices of the proximal parts as well as for the distal parts (p<0.05). CONCLUSION:Measurement of fetus MCA indices may depend to the sampling location; however, this needs further investigation in order to find a clear probe location.

OBJECTIVE:To assess studies reporting reference ranges for umbilical artery (UA) and fetal middle cerebral artery (MCA) Doppler indices and cerebroplacental ratio (CPR), using a set of predefined methodological quality criteria for study design, statistical analysis and reporting methods. METHODS:This was a systematic review of observational studies in which the primary aim was to create reference ranges for UA and MCA Doppler indices and CPR in fetuses of singleton gestations. A search for relevant articles was performed in MEDLINE, EMBASE, CINAHL, Web of Science (from inception to 31 December 2016) and references of the retrieved articles. Two authors independently selected studies, assessed the risk of bias and extracted the data. Studies were scored against a predefined set of independently agreed methodological criteria and an overall quality score was assigned to each study. Linear multiple regression analysis assessing the association between quality scores and study characteristics was performed. RESULTS:Thirty-eight studies met the inclusion criteria. The highest potential for bias was noted in the following fields: 'ultrasound quality control measures', in which only two studies demonstrated a comprehensive quality-control strategy; 'number of measurements taken for each Doppler variable', which was apparent in only three studies; 'sonographer experience', in which no study on CPR reported clearly the experience or training of the sonographers, while only three studies on UA Doppler and four on MCA Doppler did; and 'blinding of measurements', in which only one study, on UA Doppler, reported that sonographers were blinded to the measurement recorded during the examination. Sample size estimations were present in only seven studies. No predictors of quality were found on multiple regression analysis. Reference ranges varied significantly with important clinical implications for what is considered normal or abnormal, even when restricting the analysis to the highest scoring studies. CONCLUSIONS:There is considerable methodological heterogeneity in studies reporting reference ranges for UA and MCA Doppler indices and CPR, and the resulting references have important implications for clinical practice. There is a need for the standardization of methodologies for Doppler velocimetry and for the development of reference standards, which can be correctly interpreted and applied in clinical practice. We propose a set of recommendations for this purpose. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

OBJECTIVES:Myocardial tissue Doppler (MTD) is a technique for the measurement of myocardial velocities in systole and diastole. This study evaluates the use of MTD in the assessment of cardiac diastolic function in fetuses with intrauterine growth restriction (IUGR) with placental insufficiency and in appropriate-for-gestational age (AGA) fetuses with hypertensive mothers. METHODS:This study included 14 IUGR fetuses with placental insufficiency (Group 1), 13 AGA fetuses with hypertensive mothers (Group 2), and 29 AGA fetuses with healthy mothers (Group 3). Patients with other diseases were excluded. All fetuses had a gestational age of at least 25 weeks. MTD assessment was performed with the sample volume placed at the basal segment of the left ventricular side wall (LV), the interventricular septum (IVS) and the right ventricular free wall (RV). E'/A' ratios were calculated for each location. Mitral and tricuspid flows were assessed by conventional spectral pulsed Doppler. RESULTS:Significant differences were found between groups for E'/A' at the IVS (P < 0.001) and LV (P = 0.009), with a higher mean (+/- SD) value in Group 1 (IVS: 0.92 +/- 0.28; LV: 0.85 +/- 0.19) than in Groups 2 (IVS: 0.62 +/- 0.09; LV: 0.68 +/- 0.14) and 3 (IVS: 0.71 +/- 0.14; LV: 0.69 +/- 0.15). In the RV, there was no statistically significant difference in the E'/A' ratio (P = 0.2). No differences were observed for mitral and tricuspid flow velocities and ratios. CONCLUSIONS:Using MTD, the ratios between early and late diastolic myocardial velocities are higher in IUGR fetuses than in AGA fetuses at the IVS and the LV, regardless of the presence of maternal hypertension. MTD may be more sensitive than atrioventricular spectral Doppler for the detection of ventricular diastolic dysfunction in IUGR fetuses.

UNLABELLED:Aim of this study was to investigate the condition of the fetus and feto placental system in chronic pyelonephritis by identifying features in the fetoplacental blood flow and middle cerebral artery system. PATIENTS AND METHODS:We examined 68 pregnant women with chronic pyelonephritis and 50 healthy pregnant women as a control group. The study conducted a qualitative assessment of fetus and placental blood flow and blood flow in the middle cerebral artery of the fetus. The data on the condition of feto-placental blood flow and blood flow in the middle cerebral artery in the examined pregnant and control group show a higher incidence of elevated systolic and diastolic performance ratio in the umbilical artery in patients with chronic pyelonephritis than somatically healthy women. RESULTS:Studies have shown that the most accurate and informative indicator of violations feto-placental circulation is an increase in the umbilical artery whose value (2,9 and above) reflects the high degree of suffering of the fetus on a background of chronic pyelonephritis. CONCLUSIONS:Diagnostically significant is the indicator of the middle cerebral artery blood flow, which reflects the mechanism of enhancement of cerebral circulation in chronic hypoxia due to violation of feto-placental circulation in patients with renal disease.

OBJECTIVE:To investigate if placental Doppler velocimetry can predict the recurrence of a small-for-gestational age (SGA) fetus in subsequent pregnancies. DESIGN:Retrospective study. SETTING:City cohort over 15 years attending a university hospital. METHODS:A total of 196 pregnancies suspected of a SGA fetus (<3rd percentile) evaluated by uterine and umbilical artery Doppler velocimetry. Blood velocity waveform was analyzed for pulsatility index (PI) as well as the uterine artery waveform for notching in early diastole. MAIN OUTCOME MEASURE:The occurrence of a SGA newborn during the succeeding pregnancy by Doppler results from the previous pregnancy. RESULTS:In the group of 196 pregnancies suspected for SGA, 27 (13.8%) delivered a SGA newborn in the following pregnancy. Thirty-seven (18.9%) of the 196 had an abnormally high PI in the uterine arteries in their first pregnancy, 12 (32.4%) of these delivered a SGA child in the next pregnancy (relative risk 3.44, p<0.001). The corresponding figure for those with normal uterine artery PI was 15 (9.4%). Abnormal umbilical artery Doppler was a worse predictor of recurrence of SGA (p=0.051). Uterine artery notching was not related to a SGA newborn during next pregnancy. CONCLUSION:The results suggest that abnormal uterine artery Doppler is related to increased risk of recurrence of SGA during the next pregnancy. This knowledge might provide the clinician with an opportunity to initiate preventive treatment and increase surveillance to women at risk during succeeding pregnancy.

Quantitative assessment of fetal heart function has been difficult. Increasingly, tissue Doppler imaging (TDI) is used to measure fetal cardiac function noninvasively. There are two principal techniques, spectral pulsed wave (PW) TDI and color TDI (CTDI). Published reference values for fetal myocardial velocities are based on spectral PW TDI only. However, previous phantom, adult, and animal studies have shown that PW TDI velocities are systematically higher than CTDI velocities. There are no fetal studies so far. We hypothesized that myocardial velocities derived by PW TDI and CTDI are significantly different in the fetus. This prospective observational study included 91 fetuses (gestational age 28.6 ± 6.6 weeks; range 19-40 weeks) seen for routine prenatal ultrasound. From apical 4-chamber views, tricuspid ring (right ventricle), lateral and septal mitral ring were sampled by PW TDI and CTDI. Bland-Altman analysis was used for comparisons. PW and CTDI S' velocities correlated strongly in all three cardiac segments (r = 0.6 to 0.9; P < 0.01). There was a systematic bias toward higher velocities with PW TDI versus CTDI (bias 0.96 cm/s; 95% CI 1.08-0.85 cm/s). However, the strength of the correlation and bias varied depending on the region of the fetal heart sampled. PW TDI and CTDI velocity measurements are feasible in the fetus and correlate well. However, PW TDI velocities are higher than CTDI velocities with significant regional variation. This precludes a mathematical conversion of PW to CTDI in vivo. As PW TDI and color TDI vary, different reference values for fetal CTDI velocities were generated.

The purpose of this study is to investigate the use of a more biologic parameter for evaluation of the effect of nuchal cord tightness; the study of blood flow in the umbilical arteries of nuchal cord using Doppler ultrasonography. This prospective cohort study was conducted at Ain Shams University Maternity Hospital, Cairo, Egypt in the period between August 2015 and August 2017. Hundred primigravidas were recruited with nuchal cord diagnosed by Doppler ultrasonography; whereas the rest of the study population was included in the "Control group". Doppler velocimetry study was then performed on a free-floating loop of the umbilical cord and Doppler indices were calculated. Both groups were followed up during labor: intrapartum events, mode of delivery, and neonatal outcome were recorded. Intrapartum fetal heart rate abnormalities were significantly more common in the nuchal cord group compared to the control group. The overall cardiotocography category was significantly more commonly reflecting abnormal fetal heart rate patterns in the nuchal cord group compared to the control group with 46.74% of the nuchal group patients falling within the "suspicious - pathological - need urgent intervention" categories. Intervention rate was significantly higher in the nuchal cord group than the control group (33.69 versus 21.84%). Moreover, incidence of intrapartum fetal heart rate abnormalities and intervention rate were significantly higher in the nuchal cord with abnormal Doppler subgroup compared to both nuchal cord with normal Doppler subgroup and the control group; with a calculated number needed to harm of 2.11. In view of these results, it might be concluded that umbilical cord tightness affecting fetal hemodynamics (expressed by changes in umbilical artery Doppler) might be a determinate factor affecting the intrapartum course.

OBJECTIVE:To compare the maternal and fetal characteristics and perinatal outcome in mild and severe preeclampsia cases with and without uterine artery Doppler abnormalities. METHODS:Two hundred and fifty-nine mild and severe preeclampsia cases were evaluated retrospectively. Doppler measurements were done in the section where uterine artery raised from the hypogastric artery. Pulsatility index above the 95th percentile of the corresponding gestational age was accepted as abnormal. RESULTS:In mild and severe preeclampsia cases with abnormal Doppler (AD), the rate of intrauterine growth restriction, preterm birth and low birth weight was higher than, but the neonatal intensive care unit stay was similar to the cases with normal Doppler. Base excess was higher in the AD group, in mild and severe preeclampsia. The rate of low Apgar score at 5 min and perinatal mortality was higher in the AD group, in the mild preeclampsia. The strongest independent predictor of the perinatal morbidity and mortality was the presence of prematurity and of the prematurity was the presence of abnormal uterine artery Doppler. CONCLUSIONS:Maternal and perinatal morbidity and perinatal mortality increase in mild to severe preeclampsia cases with abnormal uterine artery Doppler. The abnormal uterine artery Doppler increases the morbidity and mortality by increasing the risk of prematurity.

OBJECTIVE:To determine the value of fetal Doppler indices named middle cerebral artery (MCA)-PI, umbilical artery (UA)-PI and MCA-PI/UA-PI ratio, and amniotic fluid volume assessment in pregnancies 280-294 d and their correlation with the mode of delivery and perinatal outcome. STUDY DESIGN:Prospective observational study conducted on 100 whose gestational age (GA) from 40 to 42 weeks. MCA and UA Doppler and MCA-PI/UA-PI ratio, amniotic fluid volume (AFV) were assessed. They were divided into two groups based on the presence or absence of adverse perinatal outcome. RESULTS:Women with adverse perinatal outcome showed lower MCA-PI (0.92 versus 1.29), MCA-PI:UA-PI ratio (1.04 versus 1.83), lower gestational age when assessed by ultrasound (37.82 versus 39.48 weeks), lower neonatal birth weight (2705 versus 3108 g), fetal biophysical profile (BPP) (4.55 versus 7.21) when compared to women with normal perinatal outcome. They also had higher cases with oligohydramnios (34 versus 5), and higher UA-PI (0.89 versus 0.72). CONCLUSION:Women with adverse neonatal outcome had higher UA-PI and lower MCA-PI, MCA-PI:UA-PI ratio, GA (by US), AFV, BPP, estimated fetal weight, neonatal birth weight when compared to those with normal perinatal outcome. Women with adverse neonatal outcome had a higher rate of cesarean section mostly due to fetal distress and induced VD due to oligohydraminos compared to the normal outcome group.

PURPOSE OF REVIEW:Doppler ultrasound has become an indispensable tool in evaluating pregnancies at risk for conditions such as preeclampsia, intrauterine growth restriction, fetal anemia, and umbilical cord abnormalities. Use of umbilical artery, middle cerebral artery, and uterine artery Doppler has been the mainstay of assessment. RECENT FINDINGS:Recent findings promote the use of ductus venosus Doppler to aid in timing delivery of severely growth-restricted fetuses. Whereas initially it appeared that abnormalities in ductus venosus waveform were the endpoint for pregnancies afflicted with intrauterine growth restriction, newer data suggest that these abnormalities may plateau prior to further fetal deterioration as witnessed by changes in the biophysical profile. SUMMARY:In this review, we will discuss current ultrasound Doppler literature and the recommendations of the experts. We observe that the best algorithm for incorporation of the ductus venosus into intrauterine growth restriction management is yet to be determined. This remains a subject of intense research aimed at optimizing pregnancy outcomes and will be important to follow to provide up-to-date care of our patients.

OBJECTIVE:To estimate the combined value of fetal cerebral Doppler examination and Bishop score for predicting perinatal outcome after labor induction for small-for-gestational-age (SGA) fetuses in the presence of normal umbilical artery Doppler recordings. METHODS:We conducted a cohort study in two tertiary centers, including 164 women with normal umbilical artery Doppler recordings who underwent induction of labor because of an estimated fetal weight < 10(th) percentile. The fetal middle cerebral artery pulsatility index and cerebroplacental ratio (CPR) were obtained in all cases within 24 h before induction. Cervical condition was assessed at admission using the Bishop score. A predictive model for perinatal outcomes was constructed using a decision-tree analysis algorithm. RESULTS:Both a very unfavorable cervix, defined as a Bishop score < 2, (odds ratio (OR), 3.18; 95% CI, 1.28-7.86) and an abnormal CPR (OR, 2.54; 95% CI, 1.18-5.61) were associated with an increased likelihood of emergency Cesarean section for fetal distress, but only the latter was significantly associated with the need for neonatal admission (OR, 2.43; 95% CI, 1.28-4.59). In the decision-tree analysis, both criteria significantly predicted the likelihood of Cesarean section for fetal distress. CONCLUSION:Combined use of the Bishop score and CPR improves the ability to predict overall Cesarean section (for any indication), emergency Cesarean section for fetal distress, and neonatal admission after labor induction for late-onset SGA in the presence of normal umbilical artery Doppler recordings.

OBJECTIVE:Although complications of the epidural technique are known to affect the fetus adversely, there are no data indicating that regional analgesia directly causes harmful effects to the fetus. Our purpose was to determine the effect of epidural labor analgesia on the Doppler velocimetric indices of the uterine and fetal umbilical and middle cerebral arteries. METHODS:Doppler velocimetry indices, systolic/diastolic ratios, pulsatility index, and resistance index, of the fetal umbilical artery and uterine artery were recorded in 15 women receiving continuous epidural analgesia with 0.075% bupivacaine and 0.0002% fentanyl during labor; the same indices were recorded of the fetal umbilical and middle cerebral arteries in 10 women receiving the same analgesia. The cerebroplacental Doppler ratio was calculated. Maternal and neonatal outcome data were also recorded. RESULTS:Velocimetric indices of the fetal umbilical and middle cerebral artery after epidural infusion were not significantly different from the pre-epidural infusion levels. Indices of the maternal uterine artery were significantly increased after epidural infusion. The cerebroplacental ratio did not change after the beginning of epidural infusion. Neonatal outcome parameters (1- and 5-min Apgar scores) were all within normal limits. CONCLUSIONS:These data suggest that although velocimetric indices of the maternal uterine artery are affected by continuous epidural labor analgesia, fetal circulation, as measured by Doppler velocimetric indices, is not altered.

The in-utero environment is relatively hypoxic, but fetal physiologic adaptation assures adequate tissue oxygen supply. Fetal reactions to acute or chronic hypoxia are different and are modified by the preceding fetal condition. Acute fetal hypoxia episodes are often not preventable. By contrast, good obstetric care during labor may prevent poor fetal outcome in many cases of acute fetal hypoxia. The pathophysiology of chronic fetal hypoxia caused by placental insufficiency differs from chronic fetal hypoxia seen during the last weeks of diabetic pregnancies. The efficacy of antenatal fetal surveillance methods in preventing perinatal complications is different in these two conditions. Electronic fetal heart rate testing and Doppler flow assessment methods have been successful in detecting chronic fetal hypoxia caused by placental insufficiency. However, these methods have been unable to prevent chronic fetal hypoxia complications in diabetic pregnancies. Therefore, research to find new strategies and early and reliable biomarkers is necessary to assess fetal well-being and to decide when to deliver the fetus.

The evaluation of fetal well-being by Doppler velocimetry in cases of intrauterine growth restriction (IUGR) is of great importance as it is very useful in detecting those IUGR fetuses that are at high risk because of hypoxemia. Several Doppler studies initially on fetal arteries and recently on the fetal venous system provide valuable information for the clinicians concerning the optimal time to deliver. Doppler sonography in combination with the other biophysical methods such as cardiotocogram and biophysical profile score should be used in everyday practice for the monitoring and appropriate management of the growth-restricted fetuses. The purpose of this review is to describe the current approaches in Doppler assessment of IUGR fetal circulation.

OBJECTIVE:We aimed to evaluate the outcomes of growth-restricted fetuses with absent end-diastolic velocity in the umbilical arteries (UA-AEDV), and investigate the relationship between Doppler flow velocity waveforms in the ductus venosus (DV) and the clinical features. MATERIALS AND METHODS:This was a retrospective study of growth-restricted fetuses diagnosed with UA-AEDV delivered at our institution between 2013 and 2015. The time from diagnosis of UA-AEDV to delivery, postnatal survival, and developmental prognoses were the primary outcomes. The time lag between the occurrence of UA-AEDV and an abnormal increase in the DV pulsatility index (DV-PI) were investigated. We also examined the correlation between the DV-PI values immediately before birth and umbilical cord arterial pH at birth. RESULTS:The median gestational age at birth among the 18 subjects was 28 (24-34) weeks, and the observation period between the first detection of UA-AEDV and delivery ranged from 0 to 35 days with a median of 8 days. Among the 18 infants, 15 (83%) survived, among whom 2 were diagnosed with a developmental disability. Gestational age at delivery was significantly lower in the poor outcome group. A positive correlation (correlation coefficient, 0.68) was observed between the umbilical artery pH and the last measured DV-PI. CONCLUSION:The time interval from initial detection of UA-AEDV to delivery is highly variable, and it is reasonable to manage these growth-restricted fetuses with UA-AEDV expectantly with careful surveillance for fetal well-being. Specifically, Doppler DV analysis is clinically valuable for their evaluation.

OBJECTIVE:Redistribution of cardiac output (CO) is responsible for the brain-sparing effect seen during periods of fetal stress. Our aim was to investigate prospectively the correlation between fetoplacental Doppler indices and measurements of cardiac function in uncomplicated term singleton pregnancy. METHODS:This was a prospective observational study of normotensive women with appropriately grown, non-anomalous singleton pregnancy. Participants underwent fortnightly ultrasound examinations from 36 weeks' gestation until delivery, and intrapartum and neonatal outcomes were recorded. The correlation between fetoplacental Doppler indices and various measurements of cardiac function was evaluated. RESULTS:The study cohort comprised 273 singleton pregnancies. The cerebroplacental ratio (CPR) was correlated positively with left ventricular CO (LVCO) (P < 0.001, rho = 0.29), left-to-right ventricular CO ratio (LVCO/RVCO; P < 0.001, rho = 0.41), global left ventricular strain (P < 0.01, rho = 0.17) and global right ventricular strain (P < 0.001, rho = 0.22). The CPR was correlated inversely with the left ventricular myocardial performance index (P < 0.01, rho = -0.18) and the RVCO (P < 0.001, rho = -0.28). The LVCO and global left ventricular strain were correlated positively with umbilical venous flow (P = 0.04, rho = 0.18 and P < 0.001, rho = 0.25, respectively). There was minimal or no correlation between either the mean uterine artery pulsatility index (PI) or umbilical artery PI with any cardiac indices. CONCLUSION:The fetal CPR, middle cerebral artery PI and umbilical venous flow are correlated positively with LVCO, LVCO/RVCO and global left ventricular strain in low-risk term pregnancies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Doppler sonography is widely established in prenatal medicine and obstetrics and is commonly used in screening for aneuploidy and preeclampsia during the first trimester. More importantly, during the 2nd and 3 rd trimester, it is used in the assessment of fetal health as well as the surveillance of underlying fetal conditions such as IUGR and anemia. Correct use of the method is vital for correct data interpretation and the inferred clinical decision process. Therefore, we aim to provide all users of doppler sonography with a guide for meeting the required quality standards. These quality standards will further be the basis of DEGUM-certified training courses. In the first part, we will introduce the technical principles of the method and potential error sources, vascular disciplines to which the method can be applied, analysis of the spectral curves, patient safety and the needed requirements for successful certification.

OBJECTIVE:The aim of the study was a comprehensive examination of the circulation of superior mesenteric artery in different weeks of pregnancy using Doppler ultrasound examination. METHODS:The study was conducted at the Clinic of Obstetrics and Gynecology, Jessenius Faculty of Medicine, Comenius University, Slovakia between the years 2008 and 2012. Dynamics and changes in superior mesenteric artery circulation were studied in 856 women. Results of Doppler examination were processed and subsequently evaluated for each gestational week separately. RESULTS:We found that changes in resistance index of superior mesenteric artery are slower and have a tendency to decrease as a consequence of a gradual decrease in vascular resistance. The changes in pulsatility index are different in nature; there is a tendency for there are to be repeating periods of higher and then lower values, which are subject to a more pronounced dependence on flow rate, especially end diastolic velocity, and Vmean. CONCLUSIONS:This article and its results bring a new, comprehensive view not only of physiological changes in the splanchnic circulation, but also of changes that may be subject to a certain extent, not only to the sex, but primarily to the weight of the fetus, which, of course, indirectly reflects its metabolic and respiratory demands.

OBJECTIVE:Congenital heart defect is one of the most common birth defects. The isolated ventricular septal defect (VSD) has higher morbidity, and spontaneous closure may occur. Previously many studies about the prognosis of ventricular septal defect in childhood were conducted; in contrast, few studies on evolution and prognosis of ventricular septal defect from fetus to postnatal life have been available. This research aimed to determine the evolution of isolated ventricular septal defect during the period of fetus and postnatal life, and analyze the association between the diameter or location of VSD and the spontaneous closure of VSD. METHOD:All pregnant women seen at the prenatal diagnosis center of the West China Second Hospital were recruited. From June 2011 to June 2014, these participants underwent the fetal 2-dimensional and color Doppler echocardiographic examinations, and the fetuses with isolated VSD were included in the study, and those with other malformations or abnormal chromosome were excluded. This study was a prospective and longitudinal research. These fetuses were followed-up until the VSD closed spontaneously, or were surgically repaired or percutaneously closed. Outcomes of all the cases were recorded. RESULT:There were 234 fetuses with isolated VSD who were recruited in our research cohort. Twelve of 234 lost to follow-up, 5 of 234 were still in uterus. Totally 217 fetuses were followed up. One hundred eighty-nine of 217 (87.1%) cases were delivered. The pregnancies were terminated in 28 of 217 (12.9%) cases. Ten cases died after birth. Of the 179 delivered cases, the rate of VSD spontaneous closure was 45.2% (81/179), the VSD of 49 cases (27.4%, 49/179) spontaneously closed in uterus. The VSD of 17.9% (32/179) cases spontaneously closed after birth and those of 75% (24/32) cases closed in the first year of life. Furthermore, these participants were divided into 3 groups according to the diameter of VSD in fetus. There were 87 cases in ≤ 2.0 mm group, 51 spontaneously closed (59%, 51/87) and 30 of 84 spontaneously closed (36%, 30/84) in 2.1-5.0 mm group. There were no spontaneous closure in > 5.0 mm group. There was a significant difference in spontaneous closure rate between the 3 groups (χ(2) = 15.200, P = 0.001). Nevertheless, these participants were divided into 2 groups according to the location of VSD in fetus (perimembrane VSD (P-VSD) group and muscular VSD (M-VSD) group). There were 152 cases in P-VSD group, 69 spontaneously closed (45.4%, 69/152) and 12 of 27 spontaneously closed (44%, 12/27) in M-VSD group. There was no significant difference in spontaneous closure between P-VSD and M-VSD (χ(2) = 0.008, P = 0.950). CONCLUSION:There was a high spontaneous closure rate of VSD in the period of late pregnancy. The most of postnatal VSD were spontaneously closed within one year of age. The spontaneous closure rates of fetal VSD with different diameter were different. The spontaneous closure rate of VSD with smaller diameter was higher.

BACKGROUND:Early-onset fetal growth restriction represents a particular dilemma in clinical management balancing the risk of iatrogenic prematurity with waiting for the fetus to gain more maturity, while being exposed to the risk of intrauterine death or the sequelae of acidosis. OBJECTIVE:The Trial of Umbilical and Fetal Flow in Europe was a European, multicenter, randomized trial aimed to determine according to which criteria delivery should be triggered in early fetal growth restriction. We present the key findings of the primary and secondary analyses. STUDY DESIGN:Women with fetal abdominal circumference <10th percentile and umbilical pulsatility index >95th percentile between 26-32 weeks were randomized to 1 of 3 monitoring and delivery protocols. These were: fetal heart rate variability based on computerized cardiotocography; and early or late ductus venosus Doppler changes. A safety net based on fetal heart rate abnormalities or umbilical Doppler changes mandated delivery irrespective of randomized group. The primary outcome was normal neurodevelopmental outcome at 2 years. RESULTS:Among 511 women randomized, 362/503 (72%) had associated hypertensive conditions. In all, 463/503 (92%) of fetuses survived and cerebral palsy occurred in 6/443 (1%) with known outcome. Among all women there was no difference in outcome based on randomized group; however, of survivors, significantly more fetuses randomized to the late ductus venosus group had a normal outcome (133/144; 95%) than those randomized to computerized cardiotocography alone (111/131; 85%). In 118/310 (38%) of babies delivered <32 weeks, the indication was safety-net criteria: 55/106 (52%) in late ductus venosus, 37/99 (37%) in early ductus venosus, and 26/105 (25%) in computerized cardiotocography groups. Higher middle cerebral artery impedance adjusted for gestation was associated with neonatal survival without severe morbidity (odds ratio, 1.24; 95% confidence interval, 1.02-1.52) and infant survival without neurodevelopmental impairment at 2 years (odds ratio, 1.33; 95% confidence interval, 1.03-1.72) although birthweight and gestational age were more important determinants. CONCLUSION:Perinatal and 2-year outcome was better than expected in all randomized groups. Among survivors, 2-year neurodevelopmental outcome was best in those randomized to delivery based on late ductus venosus changes. Given a high rate of delivery based on the safety-net criteria, deciding delivery based on late ductus venosus changes and abnormal computerized fetal heart rate variability seems prudent. There is no rationale for delivery based on cerebral Doppler changes alone. Of note, most women with early-onset fetal growth restriction develop hypertension.

Ductus venosus (DV) Doppler examinations in pregnancy have a widespread use for several important indications and play a crucial role in order to determine the fetal well-being. DV is usually visualized by the color Doppler mapping. We observed the instantaneous spectral flow type changes in pulsed Doppler examinations in spite of performing with the correct technique published by several authors. The variability of the pattern makes the sonographer/physician to be unsure for the correct placements of the sample gate despite fulfilling the all the criteria required for the vessel sampling. It is aimed in the study to define variations of the normal DV spectral flow types in the duration of the pulsed Doppler examinations instead of in a single cardiac cycle in normal pregnancies. This prospective study was conducted between January 2016 and February 2017. Wide-band Doppler technique was used for color mapping of the DV. Normal spectral Doppler waveforms in pregnancies are classified as types. When DV spectral flow pattern was not in the standard type, the spectral flow patterns were obtained from not only the umbilical artery and/or middle cerebral artery. Maximum and minimum blood flow velocities in the umbilical vein are measured. All Doppler examinations are performed by a single experienced specialist (CG), who had been certificated for DV flow and Doppler examinations by the Fetal Medicine Foundation. A total of seven types of flow patterns were recorded during the study period and DV flow patterns were divided into two main categories as classic flow pattern and the other patterns. The classic pattern was observed in 160 (99.4%) cases in the first trimester, 495 (94.1%) cases in the second trimester and 206 (60.8%) cases in the third trimester. We think that the fetal circulation is complicated more than estimated. There might be some endocrine agents released in the instantaneous physiologic reactions and changing the venous return abruptly or due to decreasing of the cardiac output directed to the placenta after 34 weeks influence the volume of the circulating blood in the fetus and so thereby the flow velocities instantaneously. The spectral waveform recognition approach is not reliable to identify if the DV spectral Doppler pattern is not the classic (standard) type and the DV should be visualized by wide-band color Doppler techniques particularly in the third trimester for the pulsed Doppler examinations. Studies are needed to evaluate the normal spectral variants of the flows correlated with the physiological compensatory mechanisms.

The use of Doppler ultrasound evaluation to measure the peak systolic velocity of the fetal middle cerebral artery (MCA) has been a major breakthrough in the noninvasive detection of fetal anemia. An elevated peak MCA velocity of >1.5 multiples of the median is useful in the timing of the initial intrauterine transfusion (IUT) in the red cell-alloimmunized pregnancies. Data reported to date suggest that a threshold of 1.32 multiples of the median can be used to time the second IUT; the MCA Doppler evaluation does not appear sensitive for the timing of subsequent IUTs in these pregnancies. The peak MCA velocity has also proved useful in the detection of other anemic states that include Kell alloimmunization, fetal parvovirus infection, fetomaternal hemorrhage, alphathalassemia, and after-laser therapy for twin-twin transfusion.

OBJECTIVE:We quantitatively assessed placental perfusion using three-dimensional (3D) power Doppler ultrasound for twins with selective intrauterine growth restriction (sIUGR) in one twin. STUDY DESIGN:A prospective cross-sectional study was performed for 104 normal monochorionic diamniotic twins and 30 twins with sIUGR. Twins with sIUGR were divided into two groups: in group I (19 twins), both fetuses had continuous forward end-diastolic blood flow in the umbilical artery; in group II (11 twins), the smaller fetus had a loss or a reverse end-diastolic blood flow in the umbilical artery, but the larger fetus had continuous forward end-diastolic blood flow. Volume data of the placenta was acquired in each twin at the plane where the umbilical cord entered the placenta by 3D power Doppler ultrasound, and imaging software was used to calculate the placental vascularization index (VI), flow index (FI), and vascularization flow index (VFI). RESULTS:Among smaller fetuses, the sIUGR and control groups showed significant differences in VI and VFI, as well as significant differences between sIUGR group II and control group in FI. No such differences in placental perfusion were found among larger fetuses. CONCLUSIONS:3D power Doppler ultrasound could sensitively display the varying degrees of changes in placental perfusion, which could be used for clinical monitoring of placental perfusion in sIUGR twins.

OBJECTIVES:To examine the effect of antenatal betamethasone administration on Doppler parameters of fetal and uteroplacental circulation. METHODS:Seventy-six singleton pregnancies that received betamethasone therapy were prospectively evaluated. Doppler measurements of pulsatility indices (PI) in fetal umbilical artery (UA), middle cerebral artery (MCA), ductus venosus and maternal uterine arteries were performed before (0 h) and 24, 48, 72 and 96 h after the first dose of betamethasone. Women with positive end-diastolic flow (EDF) in UA and those with absent or reversed EDF in UA were evaluated separately. RESULTS:Fifty-two women with EDF in UA and 24 women with absent or reversed flow in UA were examined. Administration of maternal betamethasone was followed by a significant decrease in the PI of the MCA at 24 h (P<0.05). Additionally, return of absent to positive, reversed to absent or from reversed to positive diastolic flow in UA was detected within 24 h in 19 (79.2%) fetuses with absent or reversed UA-EDF. All alterations were transient and maintained up to 72 h. CONCLUSIONS:Antenatal administration of betamethasone is associated with significant but transient changes in the fetal blood flow. Hence, intensive surveillance of fetuses with Doppler ultrasonography is warranted following betamethasone therapy.

INTRODUCTION:Middle cerebral artery (MCA) and umbilical artery (UA) Doppler blood flow pulsatility indices (PIs) and MCA peak systolic velocity (PSV) are essential variables for clinically evaluating fetal well-being. Here we examined how a maternal meal influenced these Doppler blood flow velocity variables. METHODS:This prospective cohort study included 89 healthy Caucasian women with normal singleton pregnancies (median age, 32 years). Measurements were performed at gestational weeks 30 and 36, representing the start and near the end of the energy-depositing period. Measured variables included the MCA-PI, UA-PI, fetal heart rate (FHR) and MCA-PSV. The cerebroplacental ratio (CPR) was calculated as the ratio of MCA-PI to UA-PI. The first examination was performed in the fasting state at 08:30 a.m. Then participants ate a standard breakfast (approximate caloric intake, 400kcal), and the examination was repeated ~105 min after the meal. RESULTS:Without adjustment for FHR, fetal MCA-PI decreased after the meal at week 30 (‒0.115; p = 0.012) and week 36 (‒0.255; p < 0.001). All PI values were negatively correlated with FHR. After adjustment for FHR, MCA-PI still decreased after the meal at week 30 (‒0.087; p = 0.044) and week 36 (‒0.194; p < 0.001). The difference between the two gestational weeks was non-significant (p = 0.075). UA-PI values did not significantly change at week 30 (p = 0.253) or week 36 (p = 0.920). CPR revealed significant postprandial decreases of -0.17 at week 30 (p = 0.006) and -0.22 at week 36 (p = 0.001). Compared to fasting values, MCA-PSV was significantly higher after food intake: +3.9 cm/s at week 30 (p < 0.001) and +5.9 cm/s at week 36 (p < 0.001). CONCLUSION:In gestational weeks 30 and 36, we observed a postprandial influence that was apparently specific to fetal cerebral blood flow.

OBJECTIVE:An objective of the Prospective Observational Trial to Optimize Pediatric Health in IUGR (PORTO) study was to evaluate multivessel Doppler changes in a large cohort of intrauterine growth restriction (IUGR) fetuses to establish whether a predictable progressive sequence of Doppler deterioration exists and to correlate these Doppler findings with respective perinatal outcomes. STUDY DESIGN:More than 1100 unselected consecutive ultrasound-dated singleton pregnancies with estimated fetal weight (EFW) less than the 10th centile were recruited between January 2010 and June 2012. Eligible pregnancies were assessed by serial Doppler interrogation of umbilical (UA) and middle cerebral (MCA) arteries, ductus venosus (DV), aortic isthmus, and myocardial performance index (MPI). Intervals between Doppler changes and patterns of deterioration were recorded and correlated with respective perinatal outcomes. RESULTS:Our study of 1116 nonanomalous fetuses comprised 7769 individual Doppler data points. Five hundred eleven patients (46%) had an abnormal UA, 300 (27%) had an abnormal MCA, and 129 (11%) had an abnormal DV Doppler. The classic pattern from abnormal UA to MCA to DV existed but no more frequently than any of the other potential pattern. Doppler interrogation of the UA and MCA remains the most useful and practical tool in identifying fetuses at risk of adverse perinatal outcome, capturing 88% of all adverse outcomes. CONCLUSION:In contrast to previous reports, we have demonstrated multiple potential patterns of Doppler deterioration in this large prospective cohort of IUGR pregnancies, which calls into question the usefulness of multivessel Doppler assessment to inform frequency of surveillance and timing of delivery of IUGR fetuses. These data will be critically important for planning any future intervention trials.

The aim of present study was to assess fetomaternal blood flows in normal and abnormal pregnancies using color Doppler indices. Subjects were divided into two groups as: Group A of 25 subjects of normal pregnancy as controls and group B of 25 subjects of pregnancy induced hypertension. All the subjects were lying in the age-group of 25-35 years and having 28 to 34 weeks of gestation; the patients were evaluated by detailed history and were subjected to complete general examination. Blood pressure was taken on two occasions at least 6 hours apart. Systemic examination and obstetrical examination was done in all subjects. All cases were subjected to pathological tests- Haemogram, Test for proteins in urine. Ultrasound assessment of fetal growth was done by measuring BPD (Biparietal diameter), HC (Head circumference), FL (Femur length) and AC (Abdominal circumference): Average gestational age and effective fetal weight was then calculated by ultrasound machine. Color Doppler was used to assess the various Doppler indices indices: Pulsatility index (PI), Resistive index (RI) and Systolic diastolic ratio (S/D ratio) in bilateral uterine, umbilical and middle cerebral arteries and compared to the standard normograms. Percentage of subjects having abnormal Doppler indices were calculated. Assessment of percentage of SGA (small for gestational age) fetuses was done in all the three groups. Decline in mean values of all Doppler indices was found with advancing gestational age in normal pregnancy suggesting decreased vascular resistance and increased blood flow in fetomaternal circulation. In pregnancy induced hypertensives, the mean values of Doppler indices showed a decline as in normal pregnancy but showed an increase (more than 2 S.D. of the mean) for that gestational age in comparison to the control group suggesting increased impedance to blood flow in uteroplacental and fetomaternal circulation. Umbilical artery Doppler indices were found to be the most sensitive indicator of uteroplacental and fetoplacental insufficiency in pregnancy induced hypertensives (P = 0.001). Thus we concluded that color Doppler can detect changes in fetomaternal circulation which correlate strongly with the fetal growth and therefore associated with pregnancy outcome.

PURPOSE:To assess the predictive power of the cerebro-placental ratio (CPR) and the venous-arterial index (VAI) for the development of intrapartum fetal distress (FD) and neonatal intensive care unit (NICU) admission. METHODS:Fetal umbilical artery, middle cerebral artery and umbilical vein Doppler measurements were obtained before the active phase of labor in 311 singleton pregnancies at ≥37 weeks. A continuous electronic fetal monitorization was applied, and an umbilical cord blood sample was obtained for each participant. FD and NICU admission were the primary outcomes. RESULTS:Labor was concluded as uncomplicated spontaneous vaginal delivery (SVD) in 261 (83.9%) cases. The 22 (7.1%) FD cases were subdivided into FD with NICU admission (n: 7; 2.3%) and without NICU admission (n: 15; 4.8%). Six out of 7 (85.8%) FD with NICU admission cases were from nulliparous pregnancies. The combinatory indices (VAI and CPR) reached the highest sensitivity (31.8%) and negative predictive value (94.7%). None of the fetuses, distressed or non-distressed, with CPR ≤ 10th percentile was born with a cord pH < 7.20. CONCLUSION:FD frequency was increased in fetuses with a low CPR or low VAI. However, the Doppler patterns were heterogeneous in both subgroups: FD with and without NICU admission. FD seems to be a common endpoint of different circulatory-metabolic disturbances. Parity affects the FD frequency in a manner related but not limited to fetal arterial and venous circulation. Low CPR could be a part of the adaptive mechanisms providing metabolic preparedness for hypoxic episodes.

PURPOSE:Assessing the biochemical markers levels and the uterine artery Doppler (UtA) parameters in fetuses with growth restriction (FGR). METHODS:Prospective case-control study included 66 patients with diagnosis of FGR and 64 healthy pregnancies at 24-41 weeks of gestation. For both groups, maternal circulating concentrations of biochemical factors of soluble fms-like tyrosine kinase-1 (sFlt-1), soluble endoglin(sEng), adiponectin, A disintegrin and metalloproteinases (ADAM-12), pregnancy-associated plasma protein-A (PAPP-A), angiopoietin-2 (ANGI-2), vascular endothelial growth factor (VEGF) and transforming growth factor-β (TGF-β) were assayed by ELISA and UtA by Doppler were performed. ANOVA, Mann-Whitney tests and Pearson correlation coefficient were applied to compare the biochemical factors, UtA Doppler and EFW Z-score between the groups. RESULTS:Concentrations of sFlt-1, sEng, PAPP-A were significantly higher in FGR than controls (p < 0.0001, p = 0.02 and p = 0.03, respectively), but concentration of ANGI-2 (p < 0.0001) was significantly lower in FGR than controls and ADAM-12 levels had a tendency to be lower in the FGR, though not statistically significant (p = 0.059). Increased sEng concentrations were correlated with abnormal UtA Doppler in FGR. CONCLUSION:Fetal growth restriction fetuses showed increased serum levels of sFlt-1, sEng and PAPP-A with levels of ANGI-2 decreased and a positive association between elevated concentrations of sEng and changing impedance of UtA Doppler were observed.

Background As conflicting results have been reported about the association of reversed flow on the aortic isthmus (AoI) and adverse perinatal results in fetal growth restriction (FGR), we aim to compare perinatal outcomes (including tolerance to labor induction) of late-onset FGR between those with anterograde and reversed AoI flow. Methods This was an observational retrospective cohort study on 148 singleton gestations diagnosed with late-onset FGR (diagnosis ≥32+0 weeks), with an estimated fetal weight (EFW) <10th centile and mild fetal Doppler alteration: umbilical artery (UA) pulsatility index (PI) >95th centile, middle cerebral artery (MCA)-PI <5th centile or cerebral-placental ratio <5th centile. Anterograde AoI flow was present in n=79 and reversed AoI flow in n=69. Delivery was recommended from 37 weeks in both groups. Perinatal results were compared between the groups. Results The global percentage of vaginal delivery of fetuses with anterograde and reversed blood flow was 55.7% vs. 66.7% (P=0.18) and the percentage of cesarean section (C-section) for non-reassuring fetal status was 12.7% vs. 15.9% (P=0.29), respectively. When evaluating those that underwent labor induction, the vaginal delivery rate was 67.9% vs. 77.2% (P=0.17), respectively. There were no significant differences regarding any other perinatal variables and there were no cases of severe morbidity or mortality. Conclusion We observed that the presence of reversed AoI flow does not worsen perinatal outcomes on fetuses with late-onset growth restriction with mild Doppler alterations. Attempt of labor induction is feasible in these fetuses regardless of the direction of AoI flow.

OBJECTIVE:To analyze the application of three-dimensional power Doppler sonography (3-DPDS) in evaluation of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) in second-trimester fetus. METHODS:Three-dimensional volume probe was used to collect the 3-DPDS blood flow images in 50 normal fetuses of 22-24 weeks and 50 fetuses of 30-32 weeks, respectively. The characteristics of three-dimensional ultrasound were analyzed. The clinical and imaging data of 4 fetuses of 26-32 weeks with midgut volvulus were analyzed retrospectively. RESULTS:The display rates of SMA and SMV were 93%in normal group by 3-DPDS and those in volvulus group were 4/4 and 3/4, respectively. The SMV trunk was parallel to and on the right side of the SMA in the normal group, while 3 cases in volvulus group showed the characteristic relationship of SMV swirling around SMA. CONCLUSIONS:3-DPDS can be used to observe the spatial relationship of SMA and SMV visually in fetus during the second trimester and is of value to diagnose and predict the outcome of midgut volvulus.

OBJECTIVES:Color tissue Doppler imaging (cTDI) is a promising tool for the assessment of fetal cardiac function. However, the analysis of myocardial velocity traces is cumbersome and time-consuming, limiting its application in clinical practice. The aim of this study was to evaluate fetal cardiac function during the second half of pregnancy and to develop reference ranges using an automated method to analyze cTDI recordings from a cardiac four-chamber view. METHODS:This was a cross-sectional study including 201 normal singleton pregnancies between 18 and 42 weeks of gestation. During fetal echocardiography, a four-chamber view of the heart was visualized and cTDI was performed. Regions of interest were positioned at the level of the atrioventricular plane in the left ventricular (LV), right ventricular (RV) and septal walls of the fetal heart, to obtain myocardial velocity traces that were analyzed offline using the automated algorithm. Peak myocardial velocities during atrial contraction (Am), ventricular ejection (Sm) and rapid ventricular filling, i.e. early diastole (Em), as well as the Em/Am ratio, mechanical cardiac time intervals and myocardial performance index (cMPI) were evaluated, and gestational age-specific reference ranges were constructed. RESULTS:At 18 weeks of gestation, the peak myocardial velocities, presented as fitted mean with 95% CI, were: LV Am, 3.39 (3.09-3.70) cm/s; LV Sm, 1.62 (1.46-1.79) cm/s; LV Em, 1.95 (1.75-2.15) cm/s; septal Am, 3.07 (2.80-3.36) cm/s; septal Sm, 1.93 (1.81-2.06) cm/s; septal Em, 2.57 (2.32-2.84) cm/s; RV Am, 4.89 (4.59-5.20) cm/s; RV Sm, 2.31 (2.16-2.46) cm/s; and RV Em, 2.94 (2.69-3.21) cm/s. At 42 weeks of gestation, the peak myocardial velocities had increased to: LV Am, 4.25 (3.87-4.65) cm/s; LV Sm, 3.53 (3.19-3.89) cm/s; LV Em, 4.55 (4.18-4.94) cm/s; septal Am, 4.49 (4.17-4.82) cm/s; septal Sm, 3.36 (3.17-3.55) cm/s; septal Em, 3.76 (3.51-4.03) cm/s; RV Am, 6.52 (6.09-6.96) cm/s; RV Sm, 4.95 (4.59-5.32) cm/s; and RV Em, 5.42 (4.99-5.88) cm/s. The mechanical cardiac time intervals generally remained more stable throughout the second half of pregnancy, although, with increased gestational age, there was an increase in duration of septal and RV atrial contraction, LV pre-ejection and septal and RV ventricular ejection, while there was a decrease in duration of septal postejection. Regression equations used for the construction of gestational age-specific reference ranges for peak myocardial velocities, Em/Am ratios, mechanical cardiac time intervals and cMPI are presented. CONCLUSION:Peak myocardial velocities increase with gestational age, while the mechanical time intervals remain more stable throughout the second half of pregnancy. Using an automated method to analyze cTDI-derived myocardial velocity traces, it was possible to construct reference ranges, which could be used in distinguishing between normal and abnormal fetal cardiac function. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

AIM:The aim of the study was to assess a relationship between the Doppler flows in foetal vessels, i.e. the middle cerebral artery (MCA), umbilical artery (UMA), umbilical vein (UV) and ductus venosus (DV) as well as in maternal vessels, i.e. the right uterine artery (UAR), left uterine artery (UAL) and the incidence of cesarean sections in pregnancies after 41 week with induced labour. MATERIALS AND METHODS:The study included 130 pregnant women, including 100 pregnant women, between 41 and 42 weeks of gestation, in whom induced labour resulted in a cesarean section due to three main indications: lack of progress of labour (Group I-44), signs of foetal distress (Group II-32) and lack of response to induced labour (Group III-24). The control group (Group IV) included 30 pregnant women between 41 and 42 completed weeks of gestation, in whom induction resulted in a physiological labour. Vascular flow was analysed in vessels, foetal, i.e. MCA, UMA, UV, DV and maternal, i.e. UAR, UAL. The procedures were conducted with the use of Medison SA 9900 vaginal and abdominal probes. RESULTS:There are observed statistically significant differences between the studied and control groups with regards to values of the variables: PSV MCA (58.64 +/-13.72 vs. 52.73 +/-10.9 p<0,05), S/D UMA (2.61 +/-1.16 vs. 2.06 +/-0.45 p<0,05), PI UMA (0.84 +/-0.23 vs. 0.7 +/-0.19 p<0,05), RI UMA (0.58 +/-0.13 vs. 0.5 +/-0.11 p<0,05). In Group II values of pulsatility index (PI) both uterine arteries are statistically significant higher (0,83 +/-0,29) than in other groups (I: 0,6 +/-0,19 p<0,05, III: . 0,61 +/-0,15 p<0,05, IV 0,64 +/-0,17 p<0,05). CONCLUSIONS:Assessment of Doppler flows in pregnancies after 41 week might allow to select pregnant women who are at a greater risk of terminating pregnancy with cesarean section after induction of labour.

OBJECTIVE:To describe changes in the Doppler waveforms of the fetal main pulmonary artery (MPA) throughout gestation and to assess their predictive value of neonatal respiratory distress syndrome (RDS). STUDY DESIGN:In the first phase of this study, we performed Doppler measurement of MPA acceleration time (AT), ejection time (ET), peak systolic velocity, end-diastolic velocity, mean velocity, pulsatility index, and resistance index in 288 healthy fetuses. In the second phase, we carried out these measurements in a prospective cohort of 52 pregnant women with impending preterm birth. RESULTS:In phase I, satisfactory fetal MPA Doppler recordings were collected in 284 of 288 (98.6%) normal fetuses. Significant and positive linear correlations were found between gestational age and AT, AT/ET ratio, peak systolic velocity, and mean velocity (p < 0.01), with the strongest correlations concerning AT (r = 0.898) and AT/ET ratio (r = 0.868). In phase II, satisfactory fetal MPA Doppler waveforms were obtained in 43 of 44 (97.7%) fetuses. Of these, 14 (32.6%) developed RDS and 29 did not. Using less than or equal to the fifth percentile as a gestational age-specific cutoff, AT alone could predict RDS with a sensitivity of 78.6% and a specificity of 89.7%. The AT/ET ratio could predict RDS with 71.4% sensitivity and 93.1% specificity. CONCLUSIONS:Fetal MPA Doppler velocimetry can reliably be obtained throughout gestation. AT and AT/ET ratios of the fetal MPA Doppler waveform may help identifying fetuses at risk of developing neonatal RDS.

PURPOSE:To determine reference values for umbilical Doppler pulsatility index in fetuses with isolated two-vessel cord and to compare these values with standard umbilical Doppler pulsatility index curves from 23 to 40 gestational weeks. METHODS:A retrospective longitudinal cohort study was conducted between January 2014 and December 2017 in a tertiary referral hospital and included 62 pregnant women with isolated single umbilical artery (two-vessel cord) and 174 measurements. Only uncomplicated term pregnancies were included. A reference curve for umbilical Doppler pulsatility index was built up and compared with a standard curve commonly used for fetuses with three-vessel cord. RESULTS:Umbilical Doppler pulsatility index values were much lower than expected in cases with two-vessel cord compared to 3-vessel cord: mean of the regression equations was 1.02 ± 0.23 vs. 0.86 ± 0.19, respectively (p value < 0.001). This difference was quite constant across the gestational weeks considered, showing that the slopes of the two regressions were very similar. CONCLUSION:Reference curves for umbilical Doppler pulsatility index in two-vessel cord pregnancies were determined. Pulsatility index values were significantly different compared with those commonly used for three-vessel cord. Using lower reference values for umbilical pulsatility index in cases with two-vessel cord may allow a better identification of fetuses affected with intrauterine growth restriction, thus improving fetal surveillance.

OBJECTIVES:The aim of the study was to investigate ultrasound and Doppler parameters in the third trimester of pregnancy as possible predictors of adverse perinatal outcome in unselected pregnancies. MATERIAL AND METHODS:We performed a retrospective cross-sectional study including unselected pregnant women be-tween 27 and 36 + 6 weeks of gestation. The following ultrasound and Doppler parameters were assessed: estimated fetal weight (EFW) [g], EFW percentile, placental maturity grade (Grannum classification), single vertical deepest pocket (SVDP) of amniotic fluid [cm], amniotic fluid index (AFI) [cm], mean uterine artery (UtA) pulsatility index (PI), umbilical artery (UA) PI, middle cerebral artery (MCA) PI, MCA peak systolic velocity (PSV) [cm/s], and cerebroplacental ratio (CPR). Adverse perinatal outcome was defined as Apgar score of < 7 at 1 min, birth weight of < 2500 g at delivery, and gestational age of < 37 weeks at delivery. The unpaired t test was used to compare the groups. RESULTS:AFI (p = 0.01), mean UtA PI (p = 0.04) and mean UA PI (p = 0.03) were significantly different with regard to the Apgar score at 1 min. EFW, EFW percentile, SVDP of amniotic fluid, AFI, mean UtA PI, UA PI, and MCA PI were significantly different (p < 0.001) in terms of birth weight. Placental maturity grade (p = 0.02), SVDP of the amniotic fluid (p < 0.001), AFI (p < 0.001), mean UtA PI (p < 0.001), UA PI (p = 0.001), and MCA PI (p < 0.001) were significantly different as far as gestational age at delivery is concerned. CONCLUSION:Ultrasound and Doppler parameters may predict adverse perinatal outcomes in unselected pregnancies in the third trimester of pregnancy.

OBJECTIVES:To use three-dimensional (3D) power Doppler ultrasound to investigate cerebral blood flow perfusion in fetuses with congenital heart disease (CHD). METHODS:The vascularization index (VI), flow index (FI) and vascularization flow index (VFI) in the total intracranial volume and the main arterial territories (middle cerebral artery (MCA), anterior cerebral artery (ACA) and posterior cerebral artery (PCA)) were evaluated prospectively and compared in 112 fetuses with CHD and 112 normal fetuses using 3D power Doppler. Correlations between the 3D power Doppler indices and neurodevelopment scores at 12 months of age were assessed in a subset of the CHD group, and values were compared with those of controls. RESULTS:Compared with the controls, the VI, FI and VFI of the total intracranial volume and the three main arteries were significantly higher in fetuses with hypoplastic left heart syndrome and left-sided obstructive lesions (P < 0.001), and the 3D power Doppler values in the ACA territory were significantly higher in fetuses with transposition of the great arteries (P < 0.01). The largest proportional increase in the blood flow perfusion indices in the fetuses with CHD relative to controls was observed in the ACA territory (P < 0.05). Among 41 cases with CHD that underwent testing, the mean Psychomotor Development Index (PDI) and Mental Development Index (MDI) scores were significantly lower than in 94 of the controls that were tested (P < 0.001). Among these CHD cases, total intracranial FI was positively correlated with PDI (r = 0.342, P = 0.029) and MDI (r = 0.339, P = 0.030), and ACA-VI and ACA-VFI were positively correlated with PDI (r = 0.377 and 0.389, P = 0.015 and 0.012, respectively) but were not correlated with MDI (r = 0.243 and 0.203, P = 0.126 and 0.204, respectively). CONCLUSIONS:Cerebral blood flow perfusion was increased relative to controls in most fetuses with CHD and was associated with neurodevelopment scores at 12 months. Prenatal 3D power Doppler ultrasound might help to identify cases of brain vasodilatation earlier and inform parental counseling.

OBJECTIVE:To assess the clinical utility of the fetal myocardial performance index (MPI) in assessment and management of the small-for-gestational-age (SGA) fetus/growth-restricted fetus (FGR). METHODS:This was a prospective cohort study in metropolitan Australia of patients referred in the period June 2012 to March 2015 to fetal medicine services at 24-38 weeks' gestation for suspected singleton SGA/FGR (estimated fetal weight (EFW) < 10 centile with or without abnormal umbilical artery (UA) Doppler) pregnancy. Patients had MPI assessed in addition to routine measures, and were followed through to birth. We compared MPI values against those of a local reference population and gestational age-matched controls, and assessed the correlation with perinatal outcome and other Doppler measures. RESULTS:Fifty-two cases were included, 38 diagnosed < 32 weeks and 14 diagnosed ≥ 32 weeks. None demonstrated significantly elevated left, right or delta MPI compared with the reference population or with gestational age-matched controls at the time of first MPI evaluation. There were no consistent longitudinal patterns in MPI that would suggest its clinical utility. The mean ± SD gestational age at delivery was 34.6 ± 3.8 weeks and birth weight was 1.7 ± 0.6 kg, and the median neonatal hospital admission time was 27 days, confirming a pathological cohort. There were no significant correlations between left, right or delta-MPI and perinatal outcome, although there were significant correlations between UA, middle cerebral artery (MCA) and ductus venosus (DV) Doppler and perinatal outcome (birth weight, gestational age at birth and length of neonatal hospital stay). Exploratory subgroup comparisons (EFW < 3 vs 3 -10 centile; early- vs late-onset; abnormal vs normal UA Doppler) found only minor differences in MPI, reaching statistical, but not clinical, significance, only in the EFW < 3 vs 3 -10 centile comparison. CONCLUSIONS:MPI did not demonstrate clinical utility in either triage or longitudinal follow-up of an SGA/FGR cohort presenting to fetal medicine services. Given that prior research suggesting its utility originates from single-center cohorts, while multicenter, large cohorts have suggested little utility or no additional utility if routine UA/MCA/DV Doppler is performed, publication bias may have affected previous reports. It seems unlikely that MPI has clinical utility in assessment and management of SGA/FGR fetuses. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

BACKGROUND:Maternal administration of corticosteroids is essential to improve fetal lung surfactant production and hasten the fetal lung maturity in women at risk for preterm birth. OBJECTIVES:The current study aims to evaluate the effects of dexamethasone on fetal and uteroplacental circulation in pregnancies at risk for preterm birth after 24 hours of its administration. METHODS:A prospective cross-sectional study was carried out in a tertiary University Hospital and included 52 pregnant women with singleton pregnancies. Doppler studies were performed on maternal uterine arteries, umbilical artery, fetal middle cerebral artery (MCA) and fetal descending aorta and just before dexamethasone administration and repeated 24 hours after completion of the course. RESULTS:There was a statistically significant difference between all Doppler indices in the umbilical artery (PI= 1.09±0.4 and 1.05±0.39, RI= 0.66±0.14 and 0.63±0.14; p=0.001), fetal MCA (RI= 0.86±0.12 and 0.83±0.13, PI= 2.19±0.72 and 2.15±0.72; p=0.001) and aorta (RI= 0.9±0.55 and 0.87±0.55; p=0.001, PI= 1.91±0.44 and 1.89±0.44; p=0.040) in comparison before and 24 hours after maternal dexamethasone administration respectively. Also uterine artery PI was significantly different (0.9±0.27 and 0.87±0.26; p=0.001). CONCLUSION:Antenatal dexamethasone for women at risk of preterm birth improves the fetal and uteroplacental blood flow at 24 hours after its administration.

OBJECTIVES:To investigate whether prenatal Doppler parameters in growth-restricted fetuses are correlated with neonatal circulatory changes. METHODS:In 43 cases of suspected fetal growth restriction (FGR), serial Doppler measurements of umbilical artery (UA) and middle cerebral artery (MCA) pulsatility index (PI) were performed. The last measurement, closest to delivery (< 1 week before birth), was used for analysis. Neonatal circulation was assessed for 2 h/day on Days 1-5, 8 and 15 by near-infrared spectroscopy (NIRS) of the cerebral, renal and splanchnic regions. We calculated fractional tissue oxygen extraction (FTOE) as: (arterial oxygen saturation - NIRS value)/arterial oxygen saturation. The following ratios were calculated: cerebroplacental ratio (CPR; MCA-PI/UA-PI), cerebrorenal ratio (CRR; cerebral/renal FTOE) and cerebrosplanchnic ratio (CSR; cerebral/splanchnic FTOE). Spearman's rank correlation coefficient (ρ) was calculated between prenatal Doppler parameters and neonatal NIRS variables. These analyses were carried out for the entire group, and separately for cases of early FGR (delivered < 34 weeks) and late FGR (≥ 34 weeks). RESULTS:Fetal Doppler parameters correlated with neonatal NIRS variables on Days 1-3: UA-PI correlated with renal FTOE (Day 1: ρ = 0.454, P < 0.01) and CRR (Day 1: ρ = -0.517, P < 0.001). MCA-PI correlated with cerebral FTOE on Day 2 (ρ = 0.469, P < 0.01), approached statistical significance on Day 3 but was not correlated on Day 1. CPR correlated with CRR (Day 1: ρ = 0.474, P < 0.01). Most associations lost their statistical significance when early and late FGR subgroups were considered separately. CONCLUSION:Low MCA-PI and low CPR, indicating brain sparing before birth, are associated with low CRR after birth, indicating relatively greater blood flow to the cerebrum than to the renal region. Based on the results of this study, it could be speculated that if brain sparing is present in the fetal circulation, it persists during the first 3 days after birth. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

OBJECTIVE:The objective of this article is to show the clinical utility of the vertebral artery Doppler as an alternative to the middle cerebral artery Doppler in the follow-up of fetuses affected with early-onset growth restriction [fetal growth restriction (FGR)]. METHODS:We present a group of fetuses with early-onset FGR in which the vertebral artery resistance index (VA RI) and pulsatility index (VA PI) were measured and plotted along with their references earlier calculated using 1980 Doppler examinations. In addition, the VA and middle cerebral artery (MCA) performance was compared using values converted into multiples of the median. RESULTS:Similar to that of the MCA, VA RI and VA PI percentiles showed curve shapes with higher values at the beginning of the third trimester. The majority of growth-restricted fetuses showed a notorious decrease in the VA impedance, which was not statistically different to that of the MCA. CONCLUSION:Vertebral artery Doppler values can be obtained throughout the second half of pregnancy. Preliminary data suggest a clinical application in the management of early-onset FGR.

OBJECTIVE:To compare Doppler ultrasonographic measurements of the fetal middle cerebral artery peak systolic velocity (MCA PSV) among women with or without gestational diabetes mellitus (GDM). METHODS:A cross-sectional study was conducted among pregnant women who presented for prenatal care at a single hospital in Brazil between September 11, 2015, and January 6, 2017. Patients were stratified into a group with GDM and a control group without GDM. One Doppler ultrasonographic assessment was performed per participant. This measurement was made after diagnosis but before the start of treatment among women in the GDM group. Fetal ultrasonographic and biometric variables assessed included MCA PSV, MCA pulsatility index, umbilical artery pulsatility index, the MCA-to-umbilical artery ratio, abdominal circumference, and weight. RESULTS:The study included 238 women: 115 in the GDM group and 123 in the control group. The median MCA PSV was 1.02 in the GDM group and 1.08 in the control group (P=0.036). No statistically significant between-group differences were found for the other fetal ultrasonographic variables or for the fetal biometric variables assessed. None of the maternal or fetal parameters assessed displayed a linear correlation with MCA PSV. CONCLUSION:Doppler ultrasonographic measurements of MCA PSV were lowered among the fetuses of women diagnosed with GDM.

The growth-restricted fetus in utero is exposed to a hostile environment and suffers undernutrition and hypoxia. To cope with the stress, the fetus changes its physiological functions. These adaptive changes aid intrauterine survival; however, they can lead to permanent functional and structural changes that can contribute to the development of serious chronic diseases later in life. Epigenetic mechanisms are an important part of the pathophysiological processes behind this "developmental origin of adult diseases." The dominant cardiovascular adaptive change is the redistribution of blood flow in hypoxic fetuses, with preferential supply of blood to the fetal brain, myocardium, and adrenal glands. The proportion of blood from the umbilical vein to the ductus venosus and foramen ovale increases, which increases the cardiac output of the left heart ventricle. The increased perfusion of fetal brain can be followed with Doppler ultrasound as increased diastolic velocities and decreased pulsatility index in the middle cerebral artery.

OBJECTIVE:Fetuses with fetal growth restrictions have higher perinatal mortality rates than fetuses without fetal growth restrictions. Vascularization of the fetal kidney is crucial to fetal growth. Hence, we assessed blood flow and vascularization of fetal kidneys in non-growth-restricted as well as growth-restricted fetuses using quantitative three-dimensional power Doppler ultrasound. MATERIALS AND METHODS:We undertook a prospective study to evaluate the vascular indices of fetal kidneys; i.e., the vascularization index, flow index and vascularization-flow index, in growth-restricted and non-growth-restricted fetuses using three-dimensional power Doppler ultrasound and quantitative three-dimensional histogram analysis. All fetuses from 20 to 40 weeks of gestation were singletons with a normal pregnancy and were followed up to delivery. RESULTS:In total, 209 fetuses without fetal growth restriction and 50 fetuses with fetal growth restriction were included. Our results showed the fetal renal vascularization index, flow index, and vascularization-flow index evaluated by three-dimensional power Doppler ultrasound can differentiate fetuses with fetal growth restriction from fetuses without fetal growth restriction. CONCLUSION:The fetal renal vascularization index, flow index, and vascularization-flow index measured by three-dimensional power Doppler ultrasound can be applied to prenatally detect fetal growth restriction. Our data support assessment of the fetal renal vascularization index, flow index, and vascularization-flow index using three-dimensional power Doppler ultrasound as a useful test for detecting fetuses with fetal growth restriction.

Evaluation of venous Doppler parameters has significantly contributed to the understanding of the vascular mechanisms that lead to fetal growth restriction (FGR) and subsequent fetal deterioration in the setting of progressive placental dysfunction. Venous redistribution of umbilical venous blood flow away from the fetal liver precedes fetal growth delay. Venous Doppler examination allows adjustment of monitoring intervals in recognition of accelerating fetal deterioration. The timing of delivery in early-onset FGR remains challenging because gestational age has an overriding effect on the neonatal outcome until the late second trimester and randomized trials of specific delivery triggers are lacking.

OBJECTIVE:Our study was conducted with an attempt to investigate the diagnostic analysis of abnormal increase of fetal pulmonary artery systolic pressure (PASP) in middle and late pregnancy by color Doppler echocardiography. METHODS:From August 2017 to January 2019, 52 fetuses with moderate or greater tricuspid high-speed regurgitation were retrospectively analyzed and selected as Group A. 88 fetuses with full-color blood flow of the two ventricles and symmetrical sizes of the cardiac cavities on both sides harboring tricuspid valve and mild regurgitation or a small amount of regurgitation were selected as Group B. The pulmonary artery blood flow acceleration time (AT) and right ventricular ejection time (ET) was measured, and the PASP was calculated. RESULTS:The tricuspid regurgitation velocity, tricuspid regurgitation pressure difference and PASP in Group A were higher than those in Group B ( < 0.05), and the AT and AT/ET values in Group A were lower than those in Group B ( < 0.05). Gestational age, tricuspid regurgitation velocity and tricuspid regurgitation pressure difference were positively correlated with PASP. However, AT/ET and AT value were negatively correlated with PASP. CONCLUSION:The abnormal increase of pulmonary artery can be assessed by color Doppler echocardiography of fetal tricuspid regurgitation, which is worth popularizing and applying in clinic. ADVANCES IN KNOWLEDGE:It was suggested that the middle- and late-stage fetuses with moderate or greater tricuspid regurgitation and with >20 mmHg regurgitation pressure difference should be followed up in clinic. If PASP was ≥70 mmHg with symptoms of right heart failure, fetuses should be closely observed until 35-36 weeks old to ensure fetal safety and early delivery would be recommended.

OBJECTIVES:The ratio of mitral peak early diastolic filling to early diastolic mitral annular velocity (E/e') reflects diastolic cardiac function in adults. Dual-gate Doppler (DD) enables measurements of E/e' in the same heart beat. This study was designed to assess the utility of the DD method for measurement of fetal E/e' and determine reference ranges for normal fetuses. METHODS:This prospective study comprised normal singleton pregnancies undergoing fetal echocardiography between 16 and 36 weeks of gestation. According to the DD method, E-wave velocity on pulsed-wave Doppler and e'-wave on tissue Doppler imaging were measured simultaneously on an apical or basal four-chamber view, and fetal E/e' was calculated. Spearman's correlation coefficient was used to assess the relationship between gestational age (GA) and E-wave and e'-wave velocities and E/e'. RESULTS:A total of 133 pregnancies were included in this study and all E/e' measurements were successful. Significant correlation was observed between GA and both left ventricular (LV) E/e' (r  = -0.666, P < 0.001) and right ventricular (RV) E/e' (r  = -0.607, P < 0.001). The regression equations for bilateral E/e' were: LV-E/e' = 17.341 - 0.631GA + 0.008 × GA (mean ± SD, R  = 0.440 ± 1.333); and RV-E/e' = 19.156 - 0.794GA + 0.012GA (R  = 0.419 ± 1.329). CONCLUSIONS:Bilateral E/e' of normal fetuses, measured using the DD method, decreased with GA, which is considered to be related to myocardial maturity. DD is a useful and convenient method for evaluating fetal E/e' in order to assess diastolic function in the prenatal period. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

OBJECTIVE:We sought to provide evidence-based guidelines for utilization of Doppler studies for fetuses with intrauterine growth restriction (IUGR). METHODS:Relevant documents were identified using PubMed (US National Library of Medicine, 1983 through 2011) publications, written in English, which describe the peripartum outcomes of IUGR according to Doppler assessment of umbilical arterial, middle cerebral artery, and ductus venosus. Additionally, the Cochrane Library, organizational guidelines, and studies identified through review of the above were utilized to identify relevant articles. Consistent with US Preventive Task Force suggestions, references were evaluated for quality based on the highest level of evidence, and recommendations were graded. RESULTS AND RECOMMENDATIONS:Summary of randomized and quasirandomized studies indicates that, among high-risk pregnancies with suspected IUGR, the use of umbilical arterial Doppler assessment significantly decreases the likelihood of labor induction, cesarean delivery, and perinatal deaths (1.2% vs 1.7%; relative risk, 0.71; 95% confidence interval, 0.52-0.98). Antepartum surveillance with Doppler of the umbilical artery should be started when the fetus is viable and IUGR is suspected. Although Doppler studies of the ductus venous, middle cerebral artery, and other vessels have some prognostic value for IUGR fetuses, currently there is a lack of randomized trials showing benefit. Thus, Doppler studies of vessels other than the umbilical artery, as part of assessment of fetal well-being in pregnancies complicated by IUGR, should be reserved for research protocols.

PURPOSE: Children with congenital heart disease (CHD) are known to have impaired neurodevelopment possibly influenced by altered cerebroplacental hemodynamics antenatally. We compared fetomaternal Doppler patterns in different CHD groups with published normative values during gestation. MATERIALS AND METHODS: Retrospective cohort study consisting of 248 CHD fetuses. Subgroups were generated according to the expected ascending aorta oxygen saturation: low portion of high oxygenated umbilical venous (UV) blood (group 1: n = 108), intermediate portion of UV blood due to intracardiac mixing with oxygen poor systemic blood (group 2: n = 103), high (group 3: n = 13) and low portion of UV blood without mixing of blood (group 4: n = 24). Doppler examination included umbilical artery and middle cerebral artery pulsatility index (UA-PI, MCA-PI), cerebroplacental ratio (CPR) and mean uterine artery (mUtA) PI. For mean comparisons at different gestational ages (GA), estimated marginal means from regression models are reported for GA 22 weeks (wks), GA 30 wks and GA 38 wks. RESULTS: Z-score transformed values of MCA-PI (zMCA-PI) were significantly lower in group 1 compared to all other subgroups at GA 30 wks (p < 0.05). At 38 wks, group 1 had significantly lower values of zMCA-PI and zCPR compared to groups 2 and 4. Group 1 fetuses showed a significant association between zMCA-PI and zCPR (negative) and GA as well as zmUtA-PI (positive) and GA compared to reference values. CONCLUSION: Our data confirm that CHD fetuses have a higher rate of cerebral redistribution in the third trimester. Changes in Doppler patterns were mainly observed in CHD with a low portion of UV blood in the ascending aorta.

OBJECTIVE:Cardiac dysfunction has been described in 60% of fetuses undergoing open myelomeningocele (MMC) repair. Routine Doppler evaluation of the umbilical artery (UA) and ductus venosus (DV) is challenging during fetal surgery. The aim of this study was to describe Doppler changes in the UA and DV in a cohort of fetuses during fetoscopic MMC repair. METHODS:This was a retrospective study of fetuses that underwent fetoscopic repair of MMC at a single institution between 2014 and 2017. Ultrasound images taken intraoperatively were analyzed to describe the changes in Doppler parameters of the UA and DV during fetoscopic MMC repair. The timing of Doppler changes was matched with the phase of surgery to determine whether a pattern to their appearance could be ascertained. RESULTS:Of the thirty-five cases of fetoscopic MMC repair performed during the study period, Doppler data were available for 15. Of these, UA Doppler data were obtained in 12 cases, and DV Doppler data were obtained in 13 cases. Of the 12 cases for which there were UA data, nine (75%) showed transient absence of end-diastolic flow (EDF), with five (41.7%) of them progressing to reversal of EDF. Of the 13 cases for which there were DV data, nine had elevated pulsatility index; however, none of them had absent or reversed blood flow during atrial contraction. Of the nine cases with absent EDF in the UA, this abnormality first appeared during fetoscopic repair in five (55.6%), after uterus exteriorization but before CO insufflation in two (22.2%), after uterus replacement but before skin closure in one (11.1%) and after CO insufflation but before the start of the MMC repair in one (11.1%). Doppler abnormalities in four fetuses with reversed EDF and in three with absent EDF resolved during surgery. Follow-up examination 1 day after surgery demonstrated resolution of UA and DV Doppler abnormalities in all fetuses. CONCLUSION:Transient Doppler abnormalities of the UA, without significant changes in the DV, can be seen during fetoscopic MMC repair. The clinical significance of these Doppler findings remains unclear due to their transient and intermittent nature. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Pre-eclampsia is the leading cause of perinatal morbidity and mortality. A full understanding of the pathogenesis of this enigmatic condition is essential if we are to develop new prophylactic and therapeutic interventions. Central to our understanding of the pathogenesis of early-onset preeclampsia is absolute utero-placental ischaemia, which is lack of placental vascular transformation in early pregnancy. By contrast, relative utero-placental ischaemia, due to a mismatch between utero-placental blood flow and increased demand for nutrients occurring later in pregnancy, may be central to the development of late-onset pre-eclampsia. These pathogenic mechanisms have advanced our understanding of this condition, leading to better prediction, screening and intervention modalities. Screening for pre-eclampsia in the first and second trimesters by investigating the maternoplacental circulation and placental hormones could identify a high-risk subgroup. The advantage of screening in the first trimester is that a prophylactic intervention is available in the form of low-dose aspirin, if started before 16 weeks' gestation in the high-risk group, resulting in a substantial reduction in severe early-onset pre-eclampsia, while identification of a high-risk group in the second trimester will lead to focused management in this group. Using a combination of cardiac Doppler, multi-vessel Doppler assessment of the foetal circulation and biomarkers in established pre-eclampsia in the third trimester could predict adverse outcomes and guide clinicians to timeous delivery. Hopefully, advances in our understanding of this enigmatic disease will lead to further prophylactic and new therapeutic interventions.

OBJECTIVES:Echocardiography is used to quantitatively characterize cardiovascular function in fetuses with cardiac abnormalities and inform decisions for fetal or perinatal interventions. It is clinically important to understand the reproducibility of these measures, particularly between testers. While studies have reported intra-observer variability and inter-observer variability, little is known about test-retest variability for these measures. We hypothesized that even in a high volume echocardiography laboratory, quantitative measurements will demonstrate higher test-retest variability compared with inter-observer variability and intra-observer variability of the same measurements. METHODS:Prospective study of uncomplicated, singleton pregnancies to evaluate fetal measures of cardiovascular function obtained by echocardiography. One sonographer obtained predefined variables, and then, a second sonographer obtained the same variables 15 minutes after the first sonographer. Separate data acquisitions were obtained by the two sonographers to evaluate test-retest variability. Intra-observer variability and inter-observer variability were also evaluated. RESULTS:Thirty fetuses between 17- and 36-week gestation were enrolled. Time-based variables had the best intra-observer agreement and inter-observer agreement (1.2%-7.4%), while 2D (7.5%-10%), M-mode (4.9%-10.1%), and velocity-time integral (VTI; 2.6%-13.8%) measurements had poorer agreement. For all variables, test-retest agreement was worse (3%-32.1%), particularly for measurement of myocardial performance index (MPI; 19.7%-21.1%), cardiac output estimation (27.2%-27.9%), and VTI-based indices (14.7%-32.1%). CONCLUSIONS:In a laboratory highly experienced in quantitative fetal echocardiography, intra-observer agreement and inter-observer agreement are good for most quantitative parameters. However, test-retest agreement is fair or poor for several variables, notably the MPI, cardiac output estimation, and VTI-based indices. Understanding how these measures vary between separate acquisitions is important for clinical interpretation and decision making.

Objectives:To construct gestation specific reference limits for fetal umbilical (UA), middle cerebral artery (MCA) pulsatility indices (PI) and the cerebroplacental ratio (CPR) in singleton pregnancies with normal BMI between 16 and 40 weeks of gestation. Methods:We ultrasonographically examined 596 fetuses from women with normal nutritional and health status and minimal environmental constraints on fetal growth. Each mother was considered only once for measurement of fetal Doppler indices, at gestations between 16 and 40 weeks in a prospective cross-sectional study. Gestational age was confirmed by fetal crown-rump length measurement between 11 and 14 weeks. Pulsatility indices of umbilical and middle cerebral arteries were measured by real time and Doppler ultrasonography. CPR ratio was calculated by dividing MCA PI by UA PI. The fetal Doppler measurements obtained from the current study were compared with commonly used reference charts. For each parameter separate polynomial regression models were fitted to estimate the gestation specific means and standard deviations, assuming that the measurements have a normal distribution at each gestational age. Results:A significant difference of fetal Doppler indices was observed between our study and previously published reference charts for most gestational weeks. The fitted 10th, 50th and 90th centiles at 40 weeks of gestation were 0.65, 0.87 and 1.08 for UA PI; 0.93, 1.32 and 1.71 MCA PI; 1.02, 1.58 and 2.13 for CPR. Conclusions:These charts can be used for better defining the normal range of fetal arterial Doppler indices. This will be useful in the diagnosis and management of fetuses with abnormal fetal growth.

Background The Doppler effect has allowed the characterization of several vessels in maternal-fetal circulation that have been used for practical purposes. Our review of the literature showed a paucity of information about fetal pulmonary artery pressure (FMPAP) and its behavior in regard to gestational age (GA). The objectives of the study were to evaluate a formula to calculate the main FMPAP and its correlation with GA. Methods A total of 337 fetuses without obvious pathology were studied prospectively using Doppler evaluation of the FMPAP. Using the fetal main pulmonary artery Doppler acceleration time (FMPAT), we obtained the FMPAP using the following formula: FMPAP=90 - (0.62×FMPAT). Regression analyses, Pearson's bivariate correlation and paired sample t-test were used when appropriate. Results FMPAT increases while FMPAP decreases with GA. Pearson's correlation coefficient for FMPAP and GA was -0.544 (P-value<0.001) and for FMPAT and GA was 0.556 (P-value<0.001). FMPAP and FMPAT were highly correlated (R=-0.972; P<0.001). Conclusion Pulmonary artery pressure in the fetus decreases with GA.

BACKGROUND:Sexual dimorphism in placental size and function has been described. Whether this influences the clinically important umbilical artery (UA) waveform remains controversial, although a few cross-sectional studies have shown sex differences in UA pulsatility index (PI). Therefore, we tested whether fetal sex influences the UA Doppler indices during the entire second half of pregnancy and aimed to establish sex-specific reference ranges for UA Doppler indices if needed. METHODS:Our main objective was to investigate gestational age-associated changes in UA Doppler indices during the second half of pregnancy and compare the values between male and female fetuses. This was a prospective longitudinal study in women with singleton low-risk pregnancies during 19-40 weeks of gestation. UA Doppler indices were serially obtained at a 4-weekly interval from a free loop of the umbilical cord using color-directed pulsed-wave Doppler ultrasonography. Sex-specific reference intervals were calculated for the fetal heart rate (HR), UA PI, resistance index (RI), and systolic/diastolic ratio (S/D) using multilevel modeling. RESULTS:Complete data from 294 pregnancies (a total of 1261 observations from 152 male and 142 female fetuses) were available for statistical analysis, and sex-specific reference ranges for the UA Doppler indices and fetal HR were established for the last half of pregnancy. UA Doppler indices were significantly associated with gestational age (P < 0.0001) and fetal HR (P < 0.0001). Female fetuses had 2-8% higher values for UA Doppler indices than male fetuses during gestational weeks 20-36 (P < 0.05), but not later. Female fetuses had higher HR from gestational week 26 until term (P < 0.05). CONCLUSIONS:We have determined gestational age-dependent sex differences in UA Doppler indices and fetal HR during the second half of pregnancy, and correspondingly established new sex-specific reference ranges intended for refining diagnostics and monitoring individual pregnancies.

OBJECTIVE:To evaluate the association of short-term variation (STV) and Doppler parameters with adverse perinatal outcome in low-risk fetuses at term. METHODS:This was a retrospective study of 1008 appropriate-for-gestational age (AGA) term fetuses. Doppler measurements [umbilical artery (UA), middle cerebral artery (MCA), and cerebroplacental ratio (CPR)] and computerized CTG (cCTG) with STV analysis were performed prior to active labor (≤ 4 cm cervical dilatation) within 72 h of delivery. The association between Doppler indices and STV values with adverse perinatal outcome was analyzed using univariate regression analysis. RESULTS:No significant association between Doppler parameters and the need for secondary cesarean delivery (CD) or operative vaginal delivery (OVD) was shown. Regarding fetuses delivered by CD due to fetal distress, regression analyzes revealed significantly higher UA PI MoM. However, the differences in MCA PI MoM and CPR MoM were not statistically significant. Fetuses with the need for emergency CD showed significantly higher UA PI MoM, lower MCA PI MoM and lower CPR MoM. Neonates with a 5-min Apgar score < 7 had significantly lower MCA PI MoM and neonatal acidosis (UA pH ≤ 7.10) showed a significant association with UA PI MoM. None of the assessed outcome parameters were significantly associated to STV. CONCLUSION:Doppler indices assessed close to delivery in low-risk fetuses at term show a moderate association with adverse outcome parameters, whereas STV does not appear to predict poor perinatal outcome in this group of fetuses.

PURPOSE:To examine the relationship between cardiac tissue Doppler and peripheral vascular Doppler measurements in fetal anemia. MATERIALS AND METHODS:We analyzed high frame rate cardiac Tissue Doppler Imaging (TDI) data files of 26 anemic fetuses. The peak systolic tissue velocity (PSV), peak systolic displacement (PD), and peak systolic strain (PS) were determined in the mid-segment of the ventricular walls (ROI 1 right ventricle (RV), ROI 2 left ventricle (LV)) and in the basal segment of the ventricular walls (ROI 3 tricuspid annulus, ROI 4 mitral annulus). TDI parameters were correlated with established fetal vascular Doppler parameters (peak systolic blood flow velocity (Vmax) in the middle cerebral artery (MCA), pulsatility index (PI) in the MCA, in the umbilical artery (UA), and in the venous duct (DV)). RESULTS:The PSV in the LV correlated significantly negatively with the PI in the MCA. Both the PSV and PD in the LV correlated significantly negatively with the PI in the UA. The PS in the RV correlated significantly negatively with the PI in the UA. The left ventricular PSV and PD correlated significantly positively with the PI in the DV. The Vmax in the MCA did not correlate with any systolic myocardial TDI parameter. CONCLUSION:In fetal anemia, peak systolic myocardial TDI parameters correlate with vascular Doppler parameters, confirming that TDI is a promising method to evaluate myocardial function in the anemic fetus. This suggests combining both techniques to quantify fetal myocardial function in anemia even more accurately, possibly allowing for the determination of the indication for intrauterine transfusion.

OBJECTIVE:To investigate the association between maternal vascular murmurs (MVMs) and fetal growth restriction (defined as small-for-gestational-age [SGA] fetus) and abnormal Doppler pulsatility index (PI) of the uterine and/or umbilical arteries. METHODS:A cross-sectional study of women aged 18 years or older with a singleton pregnancy at 28-34 weeks was conducted at Regional Hospital Viborg, Denmark, between May 1 and August 1, 2013. Ultrasound fetal biometry was performed and the Doppler PI of the umbilical and uterine arteries was determined. An estimated fetal weight (EFW) at or below the 10th percentile was defined as SGA. Microphone recordings from the lower abdomen were divided into heart valve sounds and MVMs. RESULTS:The final analysis included 63 participants, with 25 classified as SGA and 38 as non-SGA. The mean pregnancy duration was 32.4 ± 1.4 weeks. In total, 17 participants had MVMs. There was a clear association between MVMs and a composite of SGA and an abnormal PI of the uterine and/or the umbilical artery (P<0.001), but not between MVMs and SGA only (P=0.154). CONCLUSION:Maternal vascular murmurs are significantly associated with fetal growth restriction, but not with SGA per se.

BACKGROUND:Our goal was to evaluate the serial change in myocardial performance from fetus to neonate using tissue Doppler imaging (TDI). METHOD AND RESULTS:There were 37 term infants in the present study. The TDI sensor was placed at the level of the lateral mitral annulus (M-TDI), inter-ventricular septum (IVS-TDI) and the lateral tricuspid annulus (T-TDI). We measured TDI parameters from fetus to neonate. On univariate analysis, E' (cm/s), A' (cm/s), and S' (cm/s) of three ventricular walls of TDI parameters excluding E' IVS-TDI significantly decreased during the transition from fetal to neonatal circulation. E'/A' ratio, E/E' ratio and myocardial performance index (MPI) of three ventricular walls of TDI parameters excluding T-TDI MPI significantly increased during the transition from fetal to neonatal circulation. When multiple linear regression analysis with a step-wise procedure during the transition from fetus to neonate for TDI parameters was applied to variables, significant differences were noted for predicting decreases in M-TDI S' (6.55 to 3.97, p < 0.001) and IVS-TDI A', (6.69 to 4.69, p < 0.001), and increases in IVS-TDI E'/A' ratio (0.77 to 1.02, p < 0.001) and IVS-TDI E/E' ratio (8.25 to 13.65, p < 0.001). CONCLUSION:In conclusion, we found that the myocardial performances of both ventricles decreased during the transition from fetus to neonate using TDI parameters. In particular, left ventricular systolic performance was affected more than when fetal circulation changed to neonate circulation. Our findings suggest that serial change in TDI can give new information to estimate myocardial performance of the neonate.

OBJECTIVE:Doppler ultrasonographic assessment of the cerebroplacental ratio (CPR) and middle cerebral artery (MCA) is widely used as an adjunct to umbilical artery (UA) Doppler to identify fetuses at risk of adverse perinatal outcome. However, reported estimates of its accuracy vary considerably. The aim of this study was to review systematically the prognostic accuracies of CPR and MCA Doppler in predicting adverse perinatal outcome, and to compare these with UA Doppler, in order to identify whether CPR and MCA Doppler evaluation are of added value to UA Doppler. METHODS:PubMed, EMBASE, the Cochrane Library and ClinicalTrials.gov were searched, from inception to June 2016, for studies on the prognostic accuracy of UA Doppler compared with CPR and/or MCA Doppler in the prediction of adverse perinatal outcome in women with a singleton pregnancy of any risk profile. Risk of bias and concerns about applicability were assessed using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) tool. Meta-analysis was performed for multiple adverse perinatal outcomes. Using hierarchal summary receiver-operating characteristics meta-regression models, the prognostic accuracy of CPR vs MCA Doppler was compared indirectly, and CPR and MCA Doppler vs UA Doppler compared directly. RESULTS:The search identified 4693 articles, of which 128 studies (involving 47 748 women) were included. Risk of bias or suboptimal reporting was detected in 120/128 studies (94%) and substantial heterogeneity was found, which limited subgroup analyses for fetal growth and gestational age. A large variation was observed in reported sensitivities and specificities, and in thresholds used. CPR outperformed UA Doppler in the prediction of composite adverse outcome (as defined in the included studies) (P < 0.001) and emergency delivery for fetal distress (P = 0.003), but was comparable to UA Doppler for the other outcomes. MCA Doppler performed significantly worse than did UA Doppler in the prediction of low Apgar score (P = 0.017) and emergency delivery for fetal distress (P = 0.034). CPR outperformed MCA Doppler in the prediction of composite adverse outcome (P < 0.001) and emergency delivery for fetal distress (P = 0.013). CONCLUSION:Calculating the CPR with MCA Doppler can add value to UA Doppler assessment in the prediction of adverse perinatal outcome in women with a singleton pregnancy. However, it is unclear to which subgroup of pregnant women this applies. The effectiveness of the CPR in guiding clinical management needs to be evaluated in clinical trials. © 2017 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Maternal smoking is known to have adverse effects on the foetus. This study aimed to evaluate the effects of maternal smoking during pregnancy on arterial blood flow velocities in the foetal-placental-maternal circulation, and the pathophysiological relationship with placental and foetal birth weight. A total of 148 singleton pregnancies in 59 smokers and 89 non-smoking controls were examined during the 37th week of gestation. Blood flow in the maternal uterine, foetal umbilical and middle cerebral arteries was analysed with Doppler ultrasonography. Statistically significant differences in Doppler waveforms were detected in the foetal umbilical artery (UmbA) (p < 0.05), but neither in uterine nor foetal middle cerebral arteries (p > 0.05). Both infant birthweight and placental weight were significantly decreased by maternal smoking (p< 0.001 for both). Maternal smoking during pregnancy did not affect either maternal uterine or foetal middle cerebral arterial blood flow, but caused abnormal blood flow in the foetal UmbA.

OBJECTIVES:To investigate the feasibility of fetal phase-contrast (PC)-MR angiography of the descending aorta (AoD) using an MR-compatible Doppler ultrasound sensor (DUS) for fetal cardiac gating and to compare velocimetry with Doppler ultrasound measurements. METHODS:In this prospective study, 2D PC-MR angiography was performed in 12 human fetuses (mean gestational age 32.8 weeks) using an MR-compatible DUS for gating of the fetal heart at 1.5 T. Peak flow velocities in the fetal AoD were compared with Doppler ultrasound measurements performed on the same day. Reproducibility of PC-MR measurements was tested by repeated PC-MR in five fetuses. RESULTS:Dynamic PC-MR angiography in the AoD was successfully performed in all fetuses using the DUS, with an average fetal heart rate of 140 bpm (range 129-163). Time-velocity curves revealed typical arterial blood flow patterns. PC-MR mean flow velocity and mean flux were 21.2 cm/s (range 8.6-36.8) and 8.4 ml/s (range 3.2-14.6), respectively. A positive association between PC-MR mean flux and stroke volume with gestational age was obtained (r = 0.66, p = 0.02 and r = 0.63, p = 0.03). PC-MR and Doppler ultrasound peak velocities revealed a highly significant correlation (r = 0.8, p < 0.002). Peak velocities were lower for PC-MR with 69.1 cm/s (range 39-125) compared with 96.7 cm/s (range 60-142) for Doppler ultrasound (p < 0.001). Reproducibility of PC-MR was high (p > 0.05). CONCLUSION:The MR-compatible DUS for fetal cardiac gating allows for PC-MR angiography in the fetal AoD. Comparison with Doppler ultrasound revealed a highly significant correlation of peak velocities with underestimation of PC-MR velocities. This new technique for direct fetal cardiac gating indicates the potential of PC-MR angiography for assessing fetal hemodynamics. KEY POINTS:• The developed MR-compatible Doppler ultrasound sensor allows direct fetal cardiac gating and can be used for prenatal dynamic cardiovascular MRI. • The MR-compatible Doppler ultrasound sensor was successfully applied to perform intrauterine phase-contrast MR angiography of the fetal aorta, which revealed a highly significant correlation with Doppler ultrasound measurements. • As fetal flow hemodynamics is an important parameter in the diagnosis and management of fetal pathologies, fetal phase-contrast MR angiography may offer an alternative imaging method in addition to Doppler ultrasound and develop as a second line tool in the evaluation of fetal flow hemodynamics.

A uniform approach to management of fetal growth restriction (FGR) improves outcome, prevents stillbirth, and allows appropriately timed delivery. An estimated fetal weight below the tenth percentile with coexisting abnormal umbilical artery (UA), middle cerebral artery (MCA), or cerebroplacental ratio Doppler index best identifies the small fetus requiring surveillance. Placental perfusion defects are more common earlier in gestation; accordingly, early-onset (≤32 weeks of gestation) and late-onset (>32 weeks) FGR differ in clinical phenotype. In early-onset FGR, progression of UA Doppler abnormality determines clinical acceleration, while abnormal ductus venosus (DV) Doppler precedes deterioration of biophysical variables and stillbirth. Accordingly, late DV Doppler changes, abnormal biophysical variables, or an abnormal cCTG require delivery. In late-onset FGR, MCA Doppler abnormalities precede deterioration and stillbirth. However, from 34 to 38 weeks, randomized evidence on optimal delivery timing is lacking. From 38 weeks onward, the balance of neonatal versus fetal risks favors delivery.

Our practice utilizes Doppler ultrasound as one of the most objective and effective methods to assess at-risk pregnancies. This review will discuss the application of arterial and venous Doppler techniques in assessing and managing various diseases and conditions for high-risk fetuses.