Infertility affects one in six couples, with in vitro fertilization (IVF) offering many the chance of conception. Compared to the solitary oocyte produced during the natural menstrual cycle, the supraphysiological ovarian stimulation needed to produce multiple oocytes during IVF results in a dysfunctional luteal phase that can be insufficient to support implantation and maintain pregnancy. Consequently, hormonal supplementation with luteal phase support, principally exogenous progesterone, is used to optimize pregnancy rates; however, luteal phase support remains largely 'black-box' with insufficient clarity regarding the optimal timing, dosing, route and duration of treatment. Herein, we review the evidence on luteal phase support and highlight remaining uncertainties and future research directions. Specifically, we outline the physiological luteal phase, which is regulated by progesterone from the corpus luteum, and evaluate how it is altered by the supraphysiological ovarian stimulation used during IVF. Additionally, we describe the effects of the hormonal triggers used to mature oocytes on the degree of luteal phase support required. We explain the histological transformation of the endometrium during the luteal phase and evaluate markers of endometrial receptivity that attempt to identify the 'window of implantation'. We also cover progesterone receptor signalling, circulating progesterone levels associated with implantation, and the pharmacokinetics of available progesterone formulations to inform the design of luteal phase support regimens.

BACKGROUND:The study objective was to investigate whether repeated intranasal administration of a GnRH agonist could provide convenient and safe luteal support. METHODS:Twenty-four patients with unexplained infertility were enrolled. All patients were treated with an aromatase inhibitor. When ovulation trigger criteria were met, patients were randomly allocated to either 5000 IU hCG (group A), or 200 microg intranasal buserelin followed by 100 microg every 3 days (group B), 100 microg every 2 days (group C), or 100 microg every day (group D), up to day 14 of the luteal phase. All patients underwent intrauterine insemination. RESULTS:Follicular development was similar in all groups with 1.1 +/- 0.3 follicles > or = 16 mm, 229.4 +/- 95.2 pg/ml estradiol (E2) and 0.8 +/- 0.5 ng/ml progesterone (mean+/-SD). The luteal phase duration (median; 95% confidence interval) was 15 (14.1, 15.0), 14 (12.5, 15.5), 15 (11.8, 18.2) and 15 (14.4, 15.6) days in groups A, B, C and D respectively. From luteal phase day 7 onwards, progesterone levels tended to be higher in group D compared with A. On day 14 of the luteal phase, progesterone levels were 3.0 (0.8, 5.2), 1.7 (-0.5, 3.9), 3.9 (-0.7, 8.5) and 7.7 (3.4, 11.9) ng/ml in groups A, B, C and D respectively (P = 0.045). No pregnancy was recorded in group A, but there was one biochemical pregnancy in group B, one biochemical and one singleton clinical pregnancy in group C, and two singleton clinical pregnancies in group D. CONCLUSION:Intranasal administration of buserelin could be effective to provide luteal support. This treatment was associated with a good pregnancy rate (5/18, 28%).

BACKGROUND:Ovulation induction may impact endometrial receptivity due to insufficient progesterone secretion. Low progesterone is associated with poor pregnancy outcomes. OBJECTIVES:To assess the effectiveness and safety of luteal phase support (LPS) in infertile women trying to conceive by intrauterine insemination or by sexual intercourse. SEARCH METHODS:We searched the Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, LILACS, trial registries for ongoing trials, and reference lists of articles (from inception to 25 August 2021). SELECTION CRITERIA:Randomised controlled trials (RCTs) of LPS using progestogen, human chorionic gonadotropin (hCG), or gonadotropin-releasing hormone (GnRH) agonist supplementation in IUI or natural cycle. DATA COLLECTION AND ANALYSIS:We used standard methodological procedures expected by Cochrane. Our primary outcomes were live birth rate/ongoing pregnancy rate (LBR/OPR) and miscarriage.  MAIN RESULTS: We included 25 RCTs (5111 participants). Most studies were at unclear or high risk of bias. We graded the certainty of evidence as very low to low. The main limitations of the evidence were poor reporting and imprecision. 1. Progesterone supplement versus placebo or no treatment  We are uncertain if vaginal progesterone increases LBR/OPR (risk ratio (RR) 1.10, 95% confidence interval (CI) 0.81 to 1.48; 7 RCTs; 1792 participants; low-certainty evidence) or decreases miscarriage per pregnancy compared to placebo or no treatment (RR 0.70, 95% CI 0.40 to 1.25; 5 RCTs; 261 participants). There were no data on LBR or miscarriage with oral stimulation. We are uncertain if progesterone increases LBR/OPR in women with gonadotropin stimulation (RR 1.24, 95% CI 0.80 to 1.92; 4 RCTs; 1054 participants; low-certainty evidence) and oral stimulation (clomiphene citrate or letrozole) (RR 0.97, 95% CI 0.58 to 1.64; 2 RCTs; 485 participants; low-certainty evidence). One study reported on OPR in women with gonadotropin plus oral stimulation; the evidence from this study was uncertain (RR 0.73, 95% CI 0.37 to 1.42; 1 RCT; 253 participants; low-certainty evidence). Given the low certainty of the evidence, it is unclear if progesterone reduces miscarriage per clinical pregnancy in any stimulation protocol (RR 0.68, 95% CI 0.24 to 1.91; 2 RCTs; 102 participants, with gonadotropin; RR 0.67, 95% CI 0.30 to 1.50; 2 RCTs; 123 participants, with gonadotropin plus oral stimulation; and RR 0.53, 95% CI 0.25 to 1.14; 2 RCTs; 119 participants, with oral stimulation). Low-certainty evidence suggests that progesterone in all types of ovarian stimulation may increase clinical pregnancy compared to placebo (RR 1.38, 95% CI 1.10 to 1.74; 7 RCTs; 1437 participants, with gonadotropin; RR 1.40, 95% CI 1.03 to 1.90; 4 RCTs; 733 participants, with gonadotropin plus oral stimulation (clomiphene citrate or letrozole); and RR 1.44, 95% CI 1.04 to 1.98; 6 RCTs; 1073 participants, with oral stimulation). 2. Progesterone supplementation regimen  We are uncertain if there is any difference between 300 mg and 600 mg of vaginal progesterone for OPR and multiple pregnancy (RR 1.58, 95% CI 0.81 to 3.09; 1 RCT; 200 participants; very low-certainty evidence; and RR 0.50, 95% CI 0.05 to 5.43; 1 RCT; 200 participants, very low-certainty evidence, respectively). No other outcomes were reported for this comparison. There were three different comparisons between progesterone regimens. For OPR, the evidence is very uncertain for intramuscular (IM) versus vaginal progesterone (RR 0.59, 95% CI 0.34 to 1.02; 1 RCT; 225 participants; very low-certainty evidence); we are uncertain if there is any difference between oral and vaginal progesterone (RR 1.25, 95% CI 0.70 to 2.22; 1 RCT; 150 participants; very low-certainty evidence) or between subcutaneous and vaginal progesterone (RR 1.05, 95% CI 0.54 to 2.05; 1 RCT; 246 participants; very low-certainty evidence). We are uncertain if IM or oral progesterone reduces miscarriage per clinical pregnancy compared to vaginal progesterone (RR 0.75, 95% CI 0.43 to 1.32; 1 RCT; 81 participants and RR 0.58, 95% CI 0.11 to 3.09; 1 RCT; 41 participants, respectively). Clinical pregnancy and multiple pregnancy were reported for all comparisons; the evidence for these outcomes was very uncertain. Only one RCT reported adverse effects. We are uncertain if IM route increases the risk of adverse effects when compared with the vaginal route (RR 9.25, 95% CI 2.21 to 38.78; 1 RCT; 225 participants; very low-certainty evidence). 3. GnRH agonist versus placebo or no treatment  No trials reported live birth. The evidence is very uncertain about the effect of GnRH agonist in ongoing pregnancy (RR 1.10, 95% CI 0.70 to 1.74; 1 RCT; 291 participants, very low-certainty evidence), miscarriage per clinical pregnancy (RR 0.73, 95% CI 0.26 to 2.10; 2 RCTs; 79 participants, very low-certainty evidence) and clinical pregnancy (RR 1.00, 95% CI 0.68 to 1.47; 2 RCTs; 340 participants; very low-certainty evidence), and multiple pregnancy (RR 0.28, 95% CI 0.11 to 0.70; 2 RCTs; 126 participants). 4. GnRH agonist versus vaginal progesterone  The evidence for the effect of GnRH agonist injection on clinical pregnancy is very uncertain (RR 1.00, 95% CI 0.51 to 1.95; 1 RCT; 242 participants). 5. HCG injection versus no treatment  The evidence for the effect of hCG injection on clinical pregnancy (RR 0.93, 95% CI 0.40 to 2.13; 1 RCT; 130 participants) and multiple pregnancy rates (RR 1.03, 95% CI 0.22 to 4.92; 1 RCT; 130 participants) is very uncertain. 6. Luteal support in natural cycle No study evaluated the effect of LPS in natural cycle. We could not perform sensitivity analyses, as there were no studies at low risk of selection bias and not at high risk in other domains. AUTHORS' CONCLUSIONS:We are uncertain if vaginal progesterone supplementation during luteal phase is associated with a higher live birth/ongoing pregnancy rate. Vaginal progesterone may increase clinical pregnancy rate; however, its effect on miscarriage rate and multiple pregnancy rate is uncertain. We are uncertain if IM progesterone improves ongoing pregnancy rates or decreases miscarriage rate when compared to vaginal progesterone. Regarding the other reported comparisons, neither oral progesterone nor any other medication appears to be associated with an improvement in pregnancy outcomes (very low-certainty evidence).

RESEARCH QUESTION:Does luteal phase support with vaginal progesterone improve clinical pregnancy rates in patients undergoing ovarian stimulation with letrozole? DESIGN:This was a retrospective cohort study of patients undergoing ovarian stimulation with letrozole paired with intrauterine insemination (IUI) or timed intercourse (TIC) from January 2018 to October 2021. The primary outcome of clinical pregnancy rate (CPR) was calculated for cycles with and without luteal phase progesterone support. Univariate logistic regressions were done to evaluate predictor variables for CPR. Clinically important covariates including age, body mass index, anti-Müllerian hormone concentration, diagnosis of ovulatory dysfunction and multifollicular development were included in a multivariate analysis evaluating the relationship between luteal progesterone use and odds of clinical pregnancy. Secondary outcomes including spontaneous abortion, biochemical pregnancy and ectopic pregnancy were calculated. Live birth rates were calculated for cycles in a secondary analysis. RESULTS:A total of 492 letrozole ovarian stimulation cycles in 273 patients were included. Of these cycles, 387 (78.7%) used vaginal progesterone for luteal support and 105 (21.3%) did not. The unadjusted CPR per cycle was 11.6% (45/387) with progesterone and 13.3% (14/105) without progesterone (P = 0.645). After adjusting for significant covariates including age, BMI, diagnosis of ovulatory dysfunction and multifollicular development, the odds for clinical pregnancy were not significantly improved in cycles with exogenous progesterone (odds ratio [OR] 1.15, 95% confidence interval [CI] 0.48-2.75, P = 0.762). A follow-up analysis demonstrated that live birth rate was 10.7% (41/384) with and 12.5% (13/104) without luteal progesterone, respectively (P = 0.599). CONCLUSIONS:Luteal support with vaginal progesterone does not significantly improve CPR in ovarian stimulation cycles using letrozole.

RESEARCH QUESTION:Will two boluses of gonadotrophin-releasing hormone agonist (GnRHa) during hormone replacement therapy-frozen embryo transfer (HRT-FET) cycles reduce the total pregnancy loss rate? DESIGN:Randomized controlled trial including a total of 287 HRT-FET cycles performed between 2013 and 2019. After randomization participants allocated to the GnRHa group (n = 144) underwent a standard HRT protocol, supplemented with a total of two boluses of triptorelin 0.1 mg; one bolus 2 days before starting vaginal progesterone and one bolus on the 7th day of progesterone. The control group (n = 143) underwent a standard HRT-FET protocol only. RESULTS:The intention-to-treat analysis showed no significant difference in total pregnancy loss between the GnRHa group and the control group (21% versus 33%; relative risk [RR] 0.63, 95% confidence interval [CI] 0.35-1.11), nor was the biochemical pregnancy loss per positive human chorionic gonadotrophin (HCG) significantly lower in the GnRHa group (12%, 8/67) compared with the control group (25%, 18/72) (RR 0.48, 95% CI 0.22-1.02). Participants with a live birth had a significantly higher mean progesterone concentration compared with participants without a live birth (25.0 ± 12.2 versus 23.8 ± 8.9 nmol/l; P = 0.001). Furthermore, a trend for a higher live birth rate (LBR) correlated with the highest oestradiol quartile concentration (oestradiol >0.957 nmol/l). CONCLUSIONS:Although a difference of 14% in biochemical loss and 12% in total pregnancy loss in favour of GnRHa supplementation was seen this did not reach statistical difference. Luteal progesterone and oestradiol concentrations correlate with LBR in the HRT-FET cycle, emphasizing the importance of luteal serum progesterone and oestradiol monitoring.

Embryo transfer (ET) is the final step of in vitro fertilization (IVF). Different strategies have been proposed to increase the likelihood of implantation, such as post-transfer bed rest. The objective of this manuscript was to compare the clinical outcomes of embryo transfers after IVF of patients offered rest vs. early ambulation. The patient, intervention, comparison, and outcome(s) (PICO) model was used to select the study population, which included women/couples submitted to IVF and prescribed bed rest or early ambulation. Only studies including live birth (LB) as an outcome were included (www.crd.york.ac.uk/PROSPERO/CRD42020188716) A systematic search for studies was conducted on MEDLINE, ClinicalTrials.gov, PubMed, and the Cochrane Library. A librarian coordinated the searches in May 2020, which considered articles published since 1995. All original peer-reviewed articles in English were included, regardless of study design. The search retrieved 27 citations, of which 14 were eligible for full-text analysis and four accepted for inclusion. The studies included data on 21,598 patients/cycles (rest: 20,138; early ambulation: 1,460). Patients prescribed bed rest had an LB rate of 43.6% vs. 52.5% in the individuals not offered bed rest. The meta-analysis yielded an odds ratio of 0.77 (95% CI 0.5-1.2), which means patients on bed rest were 23% less likely to have a LB; nevertheless, this difference was not statistically significant. Considering that there is no difference between the two strategies, there is no evidence to recommend bed rest after embryo transfer.

Hyperglycosylated hCG (hCG-H) is a glycoprotein with the same polypeptide structure as hCG, and much larger N- and O-linked oligosaccharides. The oligosaccharides increase the molecular weight of hCG from 36,000 - 37,000 u to 40,000 - 41,000 u, depending on the extent of hyperglycosylation. hCG-H has triantennary N-linked oligosaccharides and double molecular size O-linked oligosaccharides (hexasaccharide compared with predominantly trisaccharide structures). hCG is produced by syncytiotrophoblast cells while hCG-H is made by extravillous cytotrophoblast cells. hCG-H promotes trophoblast invasion during choriocarcinoma, growth of cytotrophoblast cells and placental implantation in pregnancy. hCG-H is an independent molecule to hCG with totally separate biological functions. hCG has numerous functions during pregnancy, it promotes progesterone production, promotes angiogenesis in uterine vasculature, immuno-suppresses the invading placental tissue, promotes the growth of the uterus in line with the growth of the fetus during pregnancy, promotes the differentiation of growing cytotrophoblast cells, promotes the quiescence of contractions in the uterine myometrium during the course of pregnancy, and also has function in growth and development of fetal organs. Monoclonal antibody B152 uniquely binds hCG-H. Using this monoclonal antibody in immunometric assays permits detection of pregnancy. It also permits management of gestational trophoblastic diseases and detection of quiescent gestational trophoblastic disease. This same test can be used to differentiate of aggressive and minimally-aggressive gestational trophoblastic disease, and discrimination of patients that respond to chemotherapy and who are chemorefractory. The hCG-H test can be used to screen for Down syndrome pregnancies and predict patients likely to generate hypertensive disorder in pregnancy. It also can be used to differentiate pregnancies that will miscarry and pregnancies that will go to term.

Background:Although gonadotropin-releasing hormone (GnRH) agonist has been introduced as a beneficial luteal phase support (LPS), the optimal strategy of GnRH agonist remains unclear. This network meta-analysis was therefore performed to determine the comparative efficacy and safety of multiple-dose versus single-dose GnRH agonist protocol for LPS in patients undergoing IVF/ICSI cycles. Methods:We searched relevant studies in PubMed, Embase and the Cochrane Registry of Controlled Trials (CENTRAL) from their inception util to September 2021. Live birth, clinical pregnancy rate, multiple pregnancy rate, and clinical abortion rate was evaluated. Pairwise and network meta-analysis were conducted using RevMan and ADDIS based on random-effects model, respectively. Moreover, the prioritization of protocols based on ranking probabilities for different outcomes were performed. Results:Sixteen RCTs met our eligibility criteria. Pairwise meta-analysis showed that multiple-dose protocol of GnRH agonist was effective for increasing live birth rate (OR 1.80, 95% CI 1.15 to 2.83, =0.01) and clinical pregnancy rate (OR 1.89, 95% CI 1.01 to 3.56, =0.05) as well as decreasing clinical abortion rate (OR 0.55, 95% CI 0.34 to 0.90, =0.02). Meanwhile, single-dose protocol of GnRH agonist was effective for increasing clinical pregnancy rate (OR 1.45, 95% CI 1.11 to 1.89, =0.007) and multiple pregnancy rate (OR 2.55, 95% CI 1.12 to 5.78, =0.03). However, network meta-analysis only confirmed that multiple-dose protocol of GnRH agonist was the best efficacious strategy for live birth rate (OR 2.04, 95% CrI 1.19 to 3.93) and clinical pregnancy rate (OR 2.10, 95% CrI 1.26 to 3.54). Conclusion:Based on the results of NMA, multiple-dose protocol may be the optimal strategy for patients undergoing IVF/ICSI cycles owing to its advantage in increasing live birth and clinical pregnancy rate. Moreover, single-dose protocol may be the optimal strategy for improving multiple pregnancy rate. However, with the limitations, more RCTs are required to confirm our findings.

BACKGROUND:Previous observational studies have highlighted the negative effects of serum hormone levels at the minimum threshold during frozen embryo transfer (FET) cycles. However, still the questions regarding the maximum threshold level, and the highest allowed dosage of hormonal medications remain unresolved. The present study was conducted to determine whether there is any relationship between the serum progesterone and estradiol levels on the day of ET, and live birth rate (LBR) in patients receiving HRT in FET cycles. METHODS:In this prospective cohort study, eligible women who were undergoing their first or second FET cycles with the top graded blastocyst stage embryos were included. All patients received the same HRT regimen. FET was scheduled 5 days after administration of the first dosage of progesterone. On the morning of ET, 4-6 h after the last dose of progesterone supplementation, the serum progesterone (P ng/ml) and estradiol (E, pg/ml) levels were measured. RESULTS:Amongst the 258 eligible women that were evaluated, the overall LBR was 34.1 % (88/258). The serum P and E values were divided into four quartiles. The means of women's age and BMI were similar between the four quartiles groups. Regarding both P and E values, it was found that the LBR was significantly lower in the highest quartile group (Q) compared with the others, (P = 0.002 and P = 0.042, respectively). The analysis of the multivariable logistic regression showed that the serum level of P on ET day, was the only significant predictive variable for LBR. The ROC curve revealed a significant predictive value of serum P levels on the day of ET for LBR, with an AUC = 0.61 (95 % CI: 0.54-0.68, P = 0.002). The optimum level of serum P, with 70 % sensitivity and 50 %specificity for LBR, was 32.5 ng/ml. CONCLUSIONS:The present study suggests that a serum P4 value at the maximum threshold on the day of FET is associated with reduced LBR following blastocyst transfer. Therefore, measuring and monitoring of P levels during FET cycles might be necessary. However, the results regarding the necessity for the screening of serum E levels before ET, are still controversial, and further prospective studies are required.

BACKGROUND:Low serum progesterone on the day of frozen embryo transfer (FET) is associated with diminished pregnancy rates in artificial endometrium preparation cycles, but there is no consensus on whether strengthened luteal phase support (LPS) benefits patients with low progesterone on the FET day in artificial cycles. This single-centre, large-sample retrospective trial was designed to investigate the contribution of strengthened LPS to pregnancy outcomes for groups with low progesterone levels on the FET day in artificial endometrium preparation cycles. METHODS:Women who had undergone the first artificial endometrium preparation cycle after a freeze-all protocol in our clinic from 2016 to 2018 were classified into two groups depending on their serum progesterone levels on the FET day. Routine LPS was administered to group B (P ≥ 10.0 ng/ml on the FET day, n = 1261), and strengthened LPS (routine LPS+ im P 40 mg daily) was administered to group A (P < 10.0 ng/ml on the FET day, n = 1295). The primary endpoint was the live birth rate, and the secondary endpoints were clinical pregnancy, miscarriage and neonatal outcomes. RESULTS:The results showed that the clinical pregnancy rate was significantly lower in group A than in group B (48.4% vs 53.2%, adjusted risk ratio (aRR) 0.81, 95% confidence interval (CI) 0.68, 0.96), whereas miscarriage rates were similar between the two groups (16.0% vs 14.7%, aRR 1.09, 95% CI 0.77, 1.54). The live birth rate was slightly lower in group A than in group B (39.5% vs 43.3%, aRR 0.84, 95% CI 0.70, 1.0). Birthweights and other neonatal outcomes were similar between the two groups (P > 0.05). CONCLUSIONS:The results indicated that the serum progesterone level on the FET day was one of the risk factors predicting the chances of pregnancy in artificial endometrium preparation cycles, and strengthened LPS in patients with low progesterone on the FET day might help to provide a reasonable pregnancy outcome in artificial cycles, although further prospective evidence is needed to confirm this possibility.

STUDY QUESTION:Are progesterone (P) levels on the day before natural cycle frozen embryo transfer (NC-FET) associated with live birth rate (LBR)? SUMMARY ANSWER:Regular ovulatory women undergoing NC-FET with serum P levels <10 ng/ml on the day before blastocyst transfer have a significantly lower LBR than those with serum P levels >10 ng/ml. WHAT IS KNOWN ALREADY:The importance of serum P levels around the time of embryo transfer in patients undergoing FET under artificial endometrial preparation has been well established. However, no study has analyzed the importance of serum P levels in patients undergoing FET under a true natural endometrial preparation cycle. STUDY DESIGN, SIZE, DURATION:This was a retrospective cohort study including 294 frozen blastocyst transfers under natural cycle endometrial preparation at a university-affiliated fertility centre between January 2016 and January 2019. PARTICIPANTS/MATERIALS, SETTING, METHODS:All patients had regular menstrual cycles and underwent NC-FET with their own oocytes. Only patients who had undergone serum P measurement between 8 am and 11 am on the day before FET were included. Patients did not receive any external medication for endometrial preparation or luteal phase support. Patients were divided into two groups according to serum P levels below or above 10 ng/ml on the day before FET. Univariate analysis was carried out to describe and compare the cycle characteristics with reproductive outcomes. To evaluate the effect of P, a multivariable logistic model was fitted for each outcome after adjusting for confounding variables. MAIN RESULTS AND THE ROLE OF CHANCE:Mean serum P levels on the day before FET were significantly higher in patients who had a live birth compared to those who did not (14.5 ± 7.0 vs 12.0 ± 6.6 ng/ml, 95% CI [0.83; 4.12]). The overall clinical pregnancy rate (CPR) and LBR were 42.9% and 35.4%, respectively. Patients in the higher P group (>10 ng/ml) had a higher LBR (41.1% vs 25.7%: risk difference (RD) 15.4%, 95% CI [5; 26]) and CPR (48.6% vs 33.0%: RD 15.6%, 95% CI [4; 27]). Patients with higher serum P levels on the day before FET (63% of patients) had an improved LBR (odds ratio: 1.05; 95% CI [1.02; 1.09]). Women with serum P levels <10 ng/ml on the day before FET (37% of patients) had significantly higher weights (62.5 ± 9.9 vs 58.1 ± 7.1 kg, 95% CI [1.92; 6.90]) and BMI (22.9 ± 3.6 vs 21.6 ± 2.7 kg/m2, 95% CI [0.42; 2.25]) compared to patients with P levels >10 ng/ml. LIMITATIONS, REASONS FOR CAUTION:The main limitation of our study is its retrospective design. Other potential limitations are the detection of LH surge through urine testing and the inclusion of patients who did and did not undergo preimplantation genetic testing for aneuploidies. The protocol used in our institution for monitoring NC-FET does not look for the onset of progesterone secretion by the corpus luteum, and a slow luteinisation process or delay of corpus luteum function cannot be ruled out. WIDER IMPLICATIONS OF THE FINDINGS:We provide evidence that a minimum serum P threshold (P >10 ng/ml) might be required for improved reproductive outcomes in NC-FET. This result suggests that there are different mechanisms by which P is produced and/or distributed by each patient. This study also provides an excellent model to evaluate the impact of luteal phase defect through NC-FET. A prospective evaluation to assess whether P supplementation should be individualised according to patient's needs is necessary to support our findings. STUDY FUNDING/COMPETING INTEREST(S):No external funding was used, and there are no competing interests.

OBJECTIVE:To study the efficacy of combined administration of subcutaneous and vaginal progesterone for priming frozen blastocysts transfers, looking at progesterone levels and ART outcome. DESIGN:Retrospective study. SETTING PATIENTS:Three hundred and twenty frozen blastocyst transfer cycles conducted in 213 women aged up to 42 years, BMI between 18 and 30 kg/m, with anatomically normal uterus who underwent frozen embryo transfers (FETs) from February 2019 to December 2019 with a combined luteal-phase support (LPS) associating subcutaneous and vaginal progesterone. Patients with recurrent pregnancy loss (RPL) were excluded. RESULTS:When using combined vaginal and subcutaneous LPS, SPL >10.50 ng/mL in 95% of cases, with a minimum value of 7.02 ng/mL. CPR, OPR, and global miscarriage rates were 38.4%, 30.9%, and 19.5%, respectively. Analyzing results per quartiles, revealed that miscarriage rates were significantly inferior, and IR were higher in the upper two quartiles of serum progesterone (>21.95 ng/mL) on the day before FET, while there was no difference in CPR and OPR. CONCLUSIONS:We report ART outcome of frozen blastocyst transfers performed using a combination of vaginal and subcutaneous progesterone for LPS. ART results were honorable and SPL favorable 1-2 days before FET in 99% of cases.

OBJECTIVE:To analyze the impact on live birth rates (LBRs) of the individualized luteal phase support (termed iLPS) in patients with low serum progesterone (P) levels compared with patients without iLPS. DESIGN:Retrospective cohort study, December 1, 2018, to May 30, 2019. SETTING:Private medical center. PATIENT(S):A total of 2,275 patients checked for serum P on the day of blastocyst transfer were analyzed. During the study period, 1,299 patients showed serum P levels of ≥9.2 ng/mL, whereas 550 showed serum P levels of <9.2 ng/mL and received iLPS. Additionally, a historical group of 426 patients with serum P levels of <9.2 ng/mL but no iLPS were used for comparison. Eligible patients were aged ≤50 years with adequate endometrium morphology after receiving estrogens. Luteal phase support was provided with micronized vaginal P (MVP) to all women. Patients with personalized initiation of exogenous P according to the endometrial receptivity assay test, polyps, fibroids distorting the cavity, or hydrosalpinx were not included in the analysis. INTERVENTION(S):As routine practice since December 2018, patients with low serum P levels received an iLPS with a daily injection of 25 mg of subcutaneous P from the day of embryo transfer (ET) in addition to standard LPS (400 mg of MVP twice a day). MAIN OUTCOME MEASURE(S):Live birth rate. RESULT(S):The LBR was 44.9% in the iLPS cases vs. 45.0% in patients with normal serum P levels (crude odds ratio [OR], 1.0; 95% confidence interval [CI], 0.82-1.22). By regression analysis, low serum P levels did not affect the LBR after adjusting for possible confounders (age, oocyte origin, fresh vs. frozen, day of ET, embryo quality, number of embryos transferred) (adjusted OR, 0.99; 95% CI, 0.79-1.25). Similarly, no differences were observed in other pregnancy outcomes between groups. The LBR was significantly higher in the group of patients who received additional subcutaneous P (iLPS) compared with the historical group with low serum P levels and no iLPS (44.9% vs. 37.3%; OR, 1.37; 95% CI, 1.06-1.78). In the overall population, patients showing P levels of <9.2 ng/mL on the day of ET were slightly younger and had higher body mass index and lower estradiol and P levels during the proliferative phase compared with patients with P levels of ≥9.2 ng/mL. No differences were observed with regard to the time in between the last dose of MVP and the serum P determination. After a multivariable logistic regression analysis, only body mass index and estradiol levels in the proliferative phase reminded statistically significant. Significant differences in the LBR were observed between patients with serum P levels of <9.2 ng/mL without iLPS and patients with serum P levels of ≥9.2 ng/mL when using either own or donated oocytes. CONCLUSION(S):Individualized LPS for patients with low serum P levels produces LBRs similar to those of patients with adequate serum P levels.

RESEARCH QUESTION:Will luteal phase rescue with additional progesterone increase serum progesterone concentrations and improve reproductive outcomes in patients with low serum progesterone concentrations undergoing hormone replacement therapy (HRT) cycles? DESIGN:Case-control study including 40 consecutive patients with serum progesterone concentrations <8.75 ng/ml on the 5th day of progesterone supplementation who underwent rescue with a daily bolus of 25 mg s.c. progesterone, starting on the afternoon of the 5th day of progesterone administration. For every patient who underwent progesterone rescue, three patients matched by age, body mass index, number of previous attempts and number of blastocysts transferred, with serum progesterone concentration >8.75 ng/ml on the 5th day of progesterone administration served as controls (n = 120). The main outcome measure was ongoing pregnancy rate (OPR). RESULTS:Baseline demographic features and embryological data of the rescue and control groups were comparable. As expected, the mean serum progesterone concentration was lower in the rescue group on the 5th day of progesterone administration (7.84 ± 0.92 versus 15.32 ± 5.02 ng/ml; P < 0.001). Following rescue, the mean serum progesterone concentration on the day of vitrified-warmed embryo transfer (6th day of progesterone administration) was 33.43 ± 10.83 ng/ml (range 14.61-82.64 ng/ml), and the OPR of the rescue and control groups were comparable. CONCLUSIONS:In patients undergoing HRT vitrified-warmed blastocyst transfer with serum progesterone concentrations lower than 8.75 ng/ml 1 day prior to the scheduled embryo transfer (6th day of progesterone administration), additional supplementation with a 25 mg s.c. daily progesterone dose seems to rescue the cycle, resulting in OPR comparable to those of patients with serum progesterone >8.75 ng/ml.

BACKGROUND:The aim of this systematic review and meta-analysis was to evaluate whether the addition of GnRH agonist for luteal support in ICSI/IVF cycles enhances the probability of live birth. METHODS:Systematic literature search (MEDLINE, EMBASE, CENTRAL and RCT registries) was conducted to identify relevant randomized controlled trials published as full manuscripts. Meta-analysis of data yielded pooled risk differences (RDs) and 95% confidence intervals (CIs). A random effects model was applied for pooling the studies. RESULTS:Six relevant RCTs were identified including a total of 2012 patients. The probability of live birth rate (RD: +16%, 95% CI: +10 to +22%) was significantly higher in patients who received GnRH agonist support compared with those who did not. The subgroup analysis according to the type of GnRH analogue used for LH suppression did not change the effect observed (studies in which GnRH agonist was used during ovarian stimulation, RD: +15%, 95% CI: +5 to +23%); (studies in which GnRH antagonist was used during ovarian stimulation, RD: +19%, 95% CI: +11 to +27%). CONCLUSIONS:The best available evidence suggests that GnRH agonist addition during the luteal phase significantly increases the probability of live birth rates.

Understanding luteal maintenance during early pregnancy is of substantial biological and practical importance. Characterizing effects of early pregnancy, however, has historically been confounded by use of controls with potential exposure to early Prostaglandin F2-alpha (PGF) pulses or differences in Corpus Luteum (CL) age. To avoid this, the present study utilized bihourly blood sampling to ensure control CL (n = 6) were of a similar age to CL from pregnant animals (n = 5), yet without exposure to PGF pulses. Additionally, CL from second month of pregnancy (n = 4) were analyzed to track fate of altered genes after cessation of embryonic interferon tau (IFNT) secretion. The major alteration in gene expression in first month of pregnancy occurred in interferon-stimulated genes (ISGs), with immune/interferon signaling pathways enriched in three independent over-representation analyses. Most ISGs decreased during second month of pregnancy, though, surprisingly, some ISGs remained elevated in the second month even after cessation of IFNT secretion. Investigation of luteolytic genes found few altered transcripts, in contrast to previous reports, likely due to removal of controls exposed to PGF pulses. An exception to this trend was decreased expression of transcription factor NR4A1. Beyond luteolytic genes and ISGs, over representation analyses highlighted the prevalence of altered genes within the extracellular matrix and regulation of Insulin-like growth factor (IGF) availability, confirming results of other studies independent of luteolytic genes. These results support the idea that CL maintenance in early pregnancy is related to lack of PGF exposure, although potential roles for CL expression of diverse ISGs and other pathways activated during early pregnancy remain undefined.

OBJECTIVE:To investigate the association between luteal serum progesterone levels and frozen embryo transfer (FET) outcomes. DESIGN:Systematic review and meta-analysis. SETTING:Not applicable. PATIENT(S):Women undergoing FET. INTERVENTION(S):We conducted electronic searches of MEDLINE, PubMed, CINAHL, EMBASE, the Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Web of Science, ClinicalTrials.gov, and grey literature (not widely available) from inception to March 2021 to identify cohort studies in which the serum luteal progesterone level was measured around the time of FET. MAIN OUTCOME MEASURE(S):Ongoing pregnancy or live birth rate, clinical pregnancy rate, and miscarriage rate. RESULT(S):Among the studies analyzing serum progesterone level thresholds <10 ng/mL, a higher serum progesterone level was associated with increased rates of ongoing pregnancy or live birth (relative risk [RR] 1.47, 95% confidence interval [CI] 1.28 to 1.70), higher chance of clinical pregnancy (RR 1.31, 95% CI 1.16 to 1.49), and lower risk of miscarriage (RR 0.62, 95% CI 0.50 to 0.77) in cycles using exclusively vaginal progesterone and blastocyst embryos. There was uncertainty about whether progesterone thresholds ≥10 ng/mL were associated with FET outcomes in sensitivity analyses including all studies, owing to high interstudy heterogeneity and wide CIs. CONCLUSION(S):Our findings indicate that there may be a minimum clinically important luteal serum concentration of progesterone required to ensure an optimal endocrine milieu during embryo implantation and early pregnancy after FET treatment. Future clinical trials are required to assess whether administering higher-dose luteal phase support improves outcomes in women with a low serum progesterone level at the time of FET. PROSPERO NUMBER:CRD42019157071.

OBJECTIVE:To determine whether vaginal progesterone for programmed endometrial preparation is noninferior to intramuscular progesterone in terms of live birth rates from frozen embryo transfer (FET). DESIGN:Three-armed, randomized, controlled noninferiority trial. SETTING:Multicenter fertility clinic. PATIENT(S):A total of 1,346 volunteer subjects planning vitrified-warmed transfer of high-quality nonbiopsied blastocysts were screened, of whom 1,125 subjects were ultimately enrolled and randomly assigned to treatment. INTERVENTION(S):The subjects were randomly assigned to receive, in preparation for FET, 50 mg daily of intramuscular progesterone (control group), 200 mg twice daily of vaginal micronized progesterone plus 50 mg of intramuscular progesterone every third day (combination treatment), or 200 mg twice daily of vaginal micronized progesterone. MAIN OUTCOME MEASURE(S):The primary outcome was live birth rate per vitrified-warmed embryo transfer. The secondary outcomes were a positive serum human chorionic gonadotropin test 2 weeks after FET, biochemical pregnancy loss, clinical pregnancy, clinical pregnancy loss, total pregnancy loss, serum luteal progesterone concentration 2 weeks after FET, and patient's experience and attitudes regarding the route of progesterone administration, on the basis of a survey administered to the subjects between FET and pregnancy test. RESULT(S):A total of 1,060 FETs were completed. The live birth rate was significantly lower in women receiving only vaginal progesterone (27%) than in women receiving intramuscular progesterone (44%) or combination treatment (46%). Fifty percent of pregnancies in women receiving only vaginal progesterone ended in miscarriage. CONCLUSION(S):The live birth rate after vaginal-only progesterone replacement was significantly reduced, due primarily to an increased rate of miscarriage. Vaginal progesterone supplemented with intramuscular progesterone every third day was noninferior to daily intramuscular progesterone, offering an effective alternative regimen with fewer injections. CLINICAL TRIAL REGISTRATION NUMBER:NCT02254577.

Progesterone plays an essential role in reproductive events. Its use for luteal support in patients undergoing infertility treatment is an established practice. The different routes used to administer progesterone impact on its efficacy in luteal support: oral administration has been shown to be ineffective due to an extensive first-pass metabolism in the liver; vaginal application has a good efficacy but has drawbacks such as vaginal leakage, irritation, discomfort and uncertainty about the real dose adsorbed; finally, intramuscular administration ensures a precise dosage but can be extremely painful with, in some cases, formation of sterile abscesses. A new progesterone preparation is now available in several European and extra-European countries that combines the precise dosage of the injectable formulation with the comfort of a well-tolerated subcutaneous self-administration. The pharmacokinetic and pharmacodynamic properties of this new product are reviewed here, together with the clinical evidence obtained in two multicenter randomized clinical trials.

Natural progesterone (P4) has a unique pharmacodynamic activity and safety profile compared to the synthetic progestins. As a result, a class effect does not exist for both P4 and synthetic progestins, in terms of both their efficacy and safety. Progestogens act at the genomic level by binding to the nuclear receptors and modulating the expression of some target-genes. P4 and the synthetic progestins have a hugely variable affinity for binding not only to the P4 receptors but also to other members of the steroid receptor family including glucocorticoid receptor, androgen receptor and mineralocorticoid receptor. This leads to different and specific pharmacokinetic profiles, clinical pharmacodynamics, safety and efficacy. P4 produced in the luteal phase of the menstrual cycle has several physiological effects regulating menses and, in the pregnant uterus, controlling the development of endometrial receptivity preparing the endometrium for implantation. P4 and its associated metabolites are powerful biological agents through genomic action by the progesterone nuclear receptor with a finely tuned regulatory role throughout pregnancy, from conception until delivery. Extra-nuclear, non-classical mechanisms of action have also been identified, including steroid interactions with some membrane receptors [oxytocin receptors and γ-aminobutyric acid (GABA), and the induction of a direct relaxing effect on uterine contractility by blockage of calcium influx. The extent of activity of P4 on the central nervous system (CNS) is modulated by the route of administration: oral P4 is affected by the presence of bacteria and associated enzymes secreted in the gut, the intestinal wall and by the liver, whereas vaginal P4 is not. P4 and two important metabolites, namely, allopregnanolone (3a,5a-tetrahydroP4) and 3a,5a-tetrahydrodeoxycorticosterone, exert neuroprotective effects on neonates. They are also natural positive modulators of the neuronal GABA receptor, providing a clear pathway to explain the rapid dose-dependent psychopharmacological actions including anxiolytic, antidepressant, anaesthetic, anticonvulsant and analgesic effects. Fundamental structural differences exist between P4 and the synthetic progestins, resulting in different safety profiles when they are used during the menstrual cycle, in early and late pregnancy and in the alleviation of peri- or postmenopausal symptoms.

BACKGROUND:Characterization of pharmacokinetics is lacking for vaginal progesterone in pregnancy. Dosing of vaginal progesterone for preterm birth prevention has been empirical. Owing to pregnancy-related changes in vaginal and uterine blood flow, hepatic metabolism, renal clearance, and endogenously elevated serum progesterone, studies outside of pregnancy may not be applicable. The lack of the pharmacokinetics profile of vaginally administered progesterone in pregnancy limits the ability to define the exposure-response relationship needed to optimize dosing, which has implications for its use in research and clinical care regarding management of short cervix, prevention of recurrent preterm birth, and prevention of recurrent miscarriage. OBJECTIVE:This was a study to establish the feasibility of using serum progesterone to establish basic pharmacokinetic parameters of vaginal progesterone in pregnancy for preterm birth prevention. STUDY DESIGN:This is a prospective study of 6 low-risk singletons at 18 0/7 to 23 6/7 weeks' gestation with body mass index 20-40. Exclusion criteria were current vaginitis, abnormal Pap smear, prescription medication use, cervical length ≤25 mm, prior preterm birth, and contraindication to progesterone. Participants received a single dose of 200 mg micronized vaginal progesterone and serum progesterone levels were evaluated every 2 hours from 0 to 12 hours and then 24 hours post dose. Primary outcome was concentration/time profile of serum progesterone. RESULTS:Median (range) maternal age was 27 (21.5-33.3) years, median body mass index was 26.5 (23.3-29.0) kg/m, and median gestational age was 22.9 (21.0-23.4) weeks. Median baseline serum progesterone was 47 (40-52) ng/mL, median peak concentration was 54 (48-68) ng/mL, and median time to peak was 12 (4-15) hours. There was a trend in rising serum progesterone over baseline with a median change in peak concentration of 11 ng/mL and interquartile range of 2-22. Median percent change from baseline was an increase by 24% (interquartile range, 4%-53%). However, there was no clear elimination phase and the median area under the curve was 112 ng*h/mL with an interquartile range of -43 to 239. CONCLUSION:Unlike in nonpregnant individuals, administration of vaginal progesterone in pregnant individuals only minimally impacts systemic exposure. There is a limited trend of rising serum progesterone over baseline levels, with significant inter-individual variability. Serum progesterone is unlikely to be a good candidate for establishing pharmacokinetics or dosing of vaginal progesterone in pregnancy for preterm birth prevention.

OBJECTIVE:To develop a consensus regarding the need for luteal phase support during assisted reproductive technology (ART), and to establish the optimal compound and route of administration for this purpose. DESIGN:Review of the published literature on luteal phase support. PATIENT(S):Women undergoing assisted reproductive technologies. INTERVENTION(S):Progesterone was administered orally, vaginally, or by intramuscular (i.m.) injection to supplement the luteal phase after assisted reproductive technology (ART). MAIN OUTCOME MEASURE(S):Pregnancy following ART. RESULT(S); Gonadotropin releasing hormone (GnRH)-agonist protocols necessitate the use of luteal phase support. Progesterone and human chorionic gonadotrophin (hCG) have both been used for this purpose, with comparable outcomes. Progesterone is the product of choice, however, as it is associated with a lower incidence of ovarian hyperstimulation syndrome (OHSS). Its use is indicated up to the serum pregnancy test. Oral, i.m., and vaginal progesterone preparations are available. Intramuscular and vaginal preparations lead to comparable rates of implantation and clinical pregnancy, despite higher serum progesterone levels after i.m. injection. Oral formulations are inferior products for luteal support. Although widely used, i.m. progesterone is uncomfortable and inconvenient for patients. By contrast, the vaginal progesterone gel (Crinone 8%) is more convenient and easier to use. CONCLUSION(S):Progesterone support of the luteal phase in in vitro fertilization (IVF) cycles is indicated, though support beyond the serum pregnancy test may not be needed. The pregnancy rates after vaginal and i.m. progesterone support are comparable, despite higher serum levels after i.m. injection. Patients prefer the vaginal progesterone gel.

BACKGROUND:Bleeding in early pregnancy is strongly associated with pregnancy loss. Progesterone is essential for the maintenance of pregnancy. Several small trials have suggested that progesterone therapy may improve pregnancy outcomes in women who have bleeding in early pregnancy. METHODS:We conducted a multicenter, randomized, double-blind, placebo-controlled trial to evaluate progesterone, as compared with placebo, in women with vaginal bleeding in early pregnancy. Women were randomly assigned to receive vaginal suppositories containing either 400 mg of progesterone or matching placebo twice daily, from the time at which they presented with bleeding through 16 weeks of gestation. The primary outcome was the birth of a live-born baby after at least 34 weeks of gestation. The primary analysis was performed in all participants for whom data on the primary outcome were available. A sensitivity analysis of the primary outcome that included all the participants was performed with the use of multiple imputation to account for missing data. RESULTS:A total of 4153 women, recruited at 48 hospitals in the United Kingdom, were randomly assigned to receive progesterone (2079 women) or placebo (2074 women). The percentage of women with available data for the primary outcome was 97% (4038 of 4153 women). The incidence of live births after at least 34 weeks of gestation was 75% (1513 of 2025 women) in the progesterone group and 72% (1459 of 2013 women) in the placebo group (relative rate, 1.03; 95% confidence interval [CI], 1.00 to 1.07; P = 0.08). The sensitivity analysis, in which missing primary outcome data were imputed, resulted in a similar finding (relative rate, 1.03; 95% CI, 1.00 to 1.07; P = 0.08). The incidence of adverse events did not differ significantly between the groups. CONCLUSIONS:Among women with bleeding in early pregnancy, progesterone therapy administered during the first trimester did not result in a significantly higher incidence of live births than placebo. (Funded by the United Kingdom National Institute for Health Research Health Technology Assessment program; PRISM Current Controlled Trials number, ISRCTN14163439.).

OBJECTIVE:To investigate whether mid-luteal serum progesterone (P) exhibits significant fluctuations during a 12-h daytime period in women undergoing fertilization (IVF) and to explore whether the extent of these fluctuations could impact the interpretation of luteal progesterone levels in a clinical setting. DESIGN:Explorative pilot study. SETTING:Public hospital-based fertility unit. PATIENTS:Ten women undergoing IVF treatment. INTERVENTION:Seven days after oocyte pick-up, patients underwent frequent repeated blood sampling (every 60 min for 12 h and during two of these hours, every 15 min). Serum samples were analyzed for progesterone, estradiol, and luteinizing hormone (LH). MAIN OUTCOME MEASURES:Daytime fluctuations in s-progesterone and s-estradiol. RESULTS:There was a significant positive correlation between median P levels and the magnitude of P variations-women with median P < 60 nmol/l had clinically stable P levels throughout the day, while patients with median P > 250 nmol/l exhibited periodic P peaks of several hundred nanomoles per liter. These endogenous P fluctuations were observed irrespective of the type of stimulation protocol or mode of triggering of final oocyte maturation and despite the fact that LH was under the detection limit at the time of measurement. Simultaneously, large fluctuations were seen in s-estradiol. CONCLUSION:Monitoring of early to mid-luteal P levels in IVF cycles may be valuable in the planning of individualized luteal phase support in the attempt to increase reproductive outcomes. The prerequisite for luteal phase monitoring is, however, that the validity of a single measured P value is reliable. We show for the first time, that a single P measurement in the low progesterone patient quite accurately reflects the corpus luteum function and that the measurement can be used to detect IVF patients with a need of additional exogenous luteal P administration.

Background:Endometrial receptivity is one of the important factors in assisted reproductive technology (ART) success. In the luteal phase of an ART cycle, serum estradiol (E2) and progesterone are often placed in low levels. Supporting the luteal phase with progesterone is a usual method. Objective:To evaluate the effects of E2 supplementation plus progesterone on the luteal phase support in the antagonist protocol who have undergone intracytoplasmic sperm injection-embryo transfer cycles. Materials and Methods:In this cross-sectional study, 200 patients with antagonist stimulation protocol, who had undergone intracytoplasmic sperm injection treatment, were divided into two groups based on the use of E2 supplementation. In both groups, 400 mg progesterone suppositories (CyclogestⓇ), twice a day/vaginally, was administered starting from the day of oocyte collection until the fetal heart activity. However, in the E2 group, in addition to progesterone, 4 mg tablet of E2 was received daily. Beta hCG was checked 14 days after the embryo transfer, and the clinical pregnancy rate was the main endpoint. Results:The patients' characteristics were matched, and insignificant differences were observed, except for endometrial thickness. The clinical outcomes showed the rate of pregnancy was higher in the E2 group compared to the control group; nonetheless, statistically, there was no noticeable difference. Conclusion:E2 supplementation had no beneficial effect in the luteal phase support of IVF cycles. Nevertheless, more studies are required to confirm the supportive role of E2 supplementation for embryo implantation and to improve the outcomes in ART cycles.

OBJECTIVES:The objective of our study is to evaluate the impact of luteal phase support by hCG in intrauterine inseminations preceded by ovarian gonadotropin stimulation. METHODS:A retrospective study was conducted at the CHU of Nice between March 1, 2016 and October 31, 2017. During this period, 300 intrauterine inseminations were included in data analysis. Ovarian stimulation was performed by gonadotropins and a GnRH antagonist was added, if needed. Following a modification of standard operative procedure in the department, patients who performed an intrauterine insemination from December 1, 2016 received luteal phase support with two injections of hCG 1500 IU, performed at three days of interval. Pregnancy and ovarian hyperstimulation syndrome were the primary and secondary study endpoints, respectively. RESULTS:Out of 300 inseminations included in the analysis, 144 were performed with luteal phase support and 156 without support. No statistically significant difference in pregnancy rate was observed between these two groups (19.4% of pregnancy in the luteal phase support group and 15.38% in the group without luteal phase support, P=0.353). No ovarian hyperstimulation syndrome occurred over the course of the study. CONCLUSION:Our study shows a slight improvement of pregnancy rate in the group subjected to luteal phase support by hCG after intrauterine insemination, but the benefit was not significant. A randomised prospective study based on a large cohort could help to assess the effect of luteal phase support during intrauterine inseminations.

STUDY QUESTION:Does an individualised luteal phase support (iLPS), according to serum progesterone (P4) level the day prior to euploid frozen embryo transfer (FET), improve pregnancy outcomes when started on the day previous to embryo transfer? SUMMARY ANSWER:Patients with low serum P4 the day prior to euploid FET can benefit from the addition of daily subcutaneous P4 injections (Psc), when started the day prior to FET, and achieve similar reproductive outcomes compared to those with initial adequate P4 levels. WHAT IS KNOWN ALREADY:The ratio between FET/IVF has spectacularly increased in the last years mainly thanks to the pursuit of an ovarian hyperstimulation syndrome free clinic and the development of preimplantation genetic testing (PGT). There is currently a big concern regarding the endometrial preparation for FET, especially in relation to serum P4 levels around the time of embryo transfer. Several studies have described impaired pregnancy outcomes in those patients with low P4 levels around the time of FET, considering 10 ng/ml as one of the most accepted reference values. To date, no prospective study has been designed to compare the reproductive outcomes between patients with adequate P4 the day previous to euploid FET and those with low, but restored P4 levels on the transfer day after iLPS through daily Psc started on the day previous to FET. STUDY DESIGN, SIZE, DURATION:A prospective observational study was conducted at a university-affiliated fertility centre between November 2018 and January 2020 in patients undergoing PGT for aneuploidies (PGT-A) IVF cycles and a subsequent FET under hormone replacement treatment (HRT). A total of 574 cycles (453 patients) were analysed: 348 cycles (leading to 342 euploid FET) with adequate P4 on the day previous to FET, and 226 cycles (leading to 220 euploid FET) under iLPS after low P4 on the previous day to FET, but restored P4 levels on the transfer day. PARTICIPANTS/MATERIALS, SETTING, METHODS:Overall we included 574 HRT FET cycles (453 patients). Standard HRT was used for endometrial preparation. P4 levels were measured the day previous to euploid FET. P4 > 10.6 ng/ml was considered as adequate and euploid FET was performed on the following day (FET Group 1). P4 < 10.6 ng/ml was considered as low, iLPS was added in the form of daily Psc injections, and a new P4 analysis was performed on the following day. FET was only performed on the same day when a restored P4 > 10.6 ng/ml was achieved (98.2% of cases) (FET Group 2). MAIN RESULTS AND THE ROLE OF CHANCE:Patient's demographics and cycle parameters were comparable between both euploid FET groups (FET Group 1 and FET Group 2) in terms of age, weight, oestradiol and P4 levels and number of embryos transferred. No statistically significant differences were found in terms of clinical pregnancy rate (56.4% vs 59.1%: rate difference (RD) -2.7%, 95% CI [-11.4; 6.0]), ongoing pregnancy rate (49.4% vs 53.6%: RD -4.2%, 95% CI [-13.1; 4.7]) or live birth rate (49.1% vs 52.3%: RD -3.2%, 95% CI [-12; 5.7]). No significant differences were also found according to miscarriage rate (12.4% vs 9.2%: RD 3.2%, 95% CI [-4.3; 10.7]). LIMITATIONS, REASONS FOR CAUTION:Only iLPS through daily Psc was evaluated. The time for Psc injection was not stated and no serum P4 determinations were performed once the pregnancy was achieved. WIDER IMPLICATIONS OF THE FINDINGS:Our study provides information regarding an 'opportunity window' for improved ongoing pregnancy rates and miscarriage rates through a daily Psc injection in cases of inadequate P4 levels the day previous to FET (P4 < 10.6 ng/ml) and restored values the day of FET (P4 > 10.6 ng/ml). Only euploid FET under HRT were considered, avoiding one of the main reasons of miscarriage and implantation failure and overcoming confounding factors such as female age, embryo quality or ovarian stimulation protocols. STUDY FUNDING/COMPETING INTEREST(S):No external funding was received. B.C. reports personal fees from MSD, Merck Serono, Ferring Pharmaceuticals, IBSA and Gedeon Richter outside the submitted work. N.P. reports grants and personal fees from MSD, Merck Serono, Ferring Pharmaceuticals, Theramex and Besins International and personal fees from IBSA and Gedeon Richter outside the submitted work. The remaining authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER:NCT03740568.

The use of frozen-thawed embryo transfer (FET) has increased over the past decade with improvements in technology and increasing live birth rates. FET facilitates elective single-embryo transfer, reduces ovarian hyperstimulation syndrome, optimizes endometrial receptivity, allows time for preimplantation genetics testing, and facilitates fertility preservation. FET cycles have been associated, however, with an increased risk of hypertensive disorders of pregnancy for reasons that are not clear. Recent evidence suggests that absence of the corpus luteum (CL) could be at least partly responsible for this increased risk. In a recent prospective cohort study, programmed FET cycles (no CL) were associated with higher rates of preeclampsia and preeclampsia with severe features compared with modified natural FET cycles. FET cycles are commonly performed in the context of a programmed cycle in which the endometrium is prepared with the use of exogenous E and P. In these cycles, ovulation is suppressed and therefore the CL is absent. The CL produces not only E and P, but also vasoactive products, such as relaxin and vascular endothelial growth factor, which are not replaced in a programmed FET cycle and which are hypothesized to be important for initial placentation. Emerging evidence has also revealed other adverse obstetrical and perinatal outcomes, including postpartum hemorrhage, macrosomia, and post-term birth specifically in programmed FET cycles compared with natural FET cycles. Despite the widespread use of FET, the optimal protocol with respect to live birth rate, maternal health, and perinatal outcomes has yet to be determined. Future practice regarding FET should be based on high-quality evidence, including rigorous controlled trials.

We aimed to compare the efficacy of vaginal progesterone versus intramuscular progesterone (IMP) for luteal phase support in assisted reproductive techniques (ART). A comprehensive electronic search of four electronic databases (PubMed, Cochrane Library, Scopus, and ISI Web of Science) was performed from inception till August 2019 for randomized controlled trials (RCTs). We included studies performed different ART with the use of vaginal progesterone versus IMP for luteal phase support. Our primary outcome was clinical pregnancy rate. Our secondary outcomes were ongoing pregnancy, miscarriage, live birth rates, and satisfaction in both groups. 15 RCTs met our inclusion criteria with a total of 5656 patients. Our analysis indicated no significant differences between vaginal progesterone and IMP regarding clinical and ongoing pregnancies (RR = 0.90, 95% CI [0.80, 1.00], =.06), (RR = 0.90, 95% CI [0.76, 1.06], =.21), respectively. No significant differences were found between both routes of progesterone in miscarriage (=.98) and live birth (=.99). Subgroup analysis between fresh and frozen embryo transfer cycles in above outcomes showed no difference between progesterone routes. Vaginal progesterone was significantly associated with more satisfaction compared to IMP (<.00001). In conclusion, vaginal progesterone can be used an alternative method for luteal phase support instead of IMP in ART.

OBJECTIVE:Our aim was to study whether luteal phase support (LPS) increases the live-birth rate (LBR) in women undergoing modified natural cycle (mNC) frozen-thawed embryo transfer (FET). METHODS:In a randomized controlled trial, conducted at a university-affiliated tertiary medical center, a total of 59 patients aged 18-45 years, underwent mNC-FET. FET was performed in mNC following ovulation triggering by hCG. Patients were randomized into two groups; The No-LPS Group included 28 women who did not receive LPS, and the LPS Group included 31 women who received vaginal progesterone for LPS. The main outcome measure was LBR. RESULTS:Baseline demographic and clinical characteristics were comparable between the study groups. The no-LPS group and the LPS group did not differ with regard to clinical pregnancy rate (21.4% vs. 32.3%; respectively,  = .35), LBR (17.9% vs. 19.4%; respectively,  = .88), or spontaneous miscarriage rate (3.6% vs. 12.9%; respectively,  = .35). On multivariate logistic regression analysis, LPS was not associated with LBR after controlling for confounders. CONCLUSION:The results of our study suggest that LPS after mNC-FET does not improve the reproductive outcome, and therefore, might not be necessary. NCT01483365.

RESEARCH QUESTION:Gonadotrophin releasing hormone (GnRH) agonist trigger after GnRH antagonist-based ovarian stimulation protocol for IVF is gaining popularity, because it prevents ovarian hyperstimulation syndrome and allows for near physiological LH and FSH surges. A small dose of HCG (1500 IU) on the day of oocyte retrieval, followed by daily progesterone administration, is currently the preferred way to secure adequate luteal support after GnRH agonist trigger. In the present study, the possibility that a bolus of 1500 IU HCG, given 2 days after oocyte retrieval, may be sufficient to sustain adequate luteal support without additional progesterone treatment was questioned. DESIGN:A non-interventional retrospective cohort study between conducted between April 2017 and August 2018. A total of 154 consecutive patients treated with GnRH agonist trigger followed by day-2 HCG (1500 IU) support only (study group) were included. Data were compared with 155 consecutive patients who were treated with HCG (6500 IU) trigger followed by conventional progesterone luteal support (control group). RESULTS:Pregnancy, miscarriage and live birth rates were comparable between the study and control groups. In patients who became pregnant, mean oestradiol level 14 days after oocyte retrieval was 4719 pmol/l and 2672 pmol/l in the study and control group, respectively (P < 0.001), reflecting robust luteal activity in the study group. CONCLUSIONS:A bolus of 1500 IU HCG, administered 2 days after retrieval, can provide excellent luteal support, without the need for further progesterone supplementation.

RESEARCH QUESTION:Do serum progesterone levels determine ongoing pregnancy rates (OPR) in hormone replacement therapy frozen-thawed embryo transfer (HRT-FET) cycles? DESIGN:A cohort study of 244 HRT-FET cycles from a Danish public fertility centre. Data from patients undergoing HRT-FET from January 2016 to December 2017 were extracted from a clinical database. All patients had transfer in HRT cycles of autologous embryos frozen on day 5 or 6. Endometrial preparation was performed using 6 mg oestradiol valerate daily from the second day of the cycle followed by vaginal micronized progesterone (90 mg/8 h). All patients had serum progesterone measurement during the artificial luteal phase. RESULTS:The optimal cut-off for ongoing pregnancy was 35 nmol/l based on sensitivity analysis of different progesterone levels as a factor variable and its association with ongoing pregnancy. No significant differences regarding number of embryos transferred, embryo quality, age, body mass index (BMI) or smoking were found in the two groups of progesterone < 35 nmol/l and ≥ 35 nmol/l, respectively. A total of 51% of patients had a serum progesterone < 35 nmol/l. The range of all measurements was 0.3 to 110 nmol/l. The unadjusted OPR was significantly lower in the < 35 nmol/l group compared with the ≥ 35 nmol/l group (38% versus 51%;P = 0.04). A logistic regression analysis, adjusting for smoking, age, BMI, number of embryos transferred and blastocyst age showed a significant decrease in OPR when progesterone was < 35 nmol/l of 44% (95% confidence interval [CI] 35-54%) compared with ≥ 35 nmol/l of 58% (95% CI 48-68%), risk difference of 14% (95% CI 2-26%,P = 0.02). CONCLUSIONS:Serum progesterone levels < 35 nmol/l decrease the chance of OPR in HRT-FET cycles.

OBJECTIVE:To compare the outcomes of luteal phase support by micronized progesteron vaginal capsule 600mg/day and progesterone vaginal gel 180mg/day in the normoresponder IVF/ICSI-ET cycles of the patients down-regulated via GnRH agonist long protocol or fixed antagonist protocol below 40 years of age. METHODS:A total of 463 normoresponder cycles between January 2013 and December 2013 were retrospectively analyzed. Those with a BMI>28 kg/m(2), any kind of uterine, ovarian or adnexial pathology, any significant systemic, endocrine or metabolic disease or who were reported as azoospermia, were excluded from the study. The patients were grouped according to the usage of micronized progesterone vaginal capsule 600mg/day (Group 1) or progesterone vaginal gel 180mg/day (Group 2) as luteal phase support. Treatment cycle characteristics and pregnancy outcomes were compared between groups. RESULTS:Group-I included 220 cycles and group 2 included 243 cycles. Although the MII oocyte percentage among the total number of MII oocytes was significantly higher in Group-II (77.5% and 80.2%; p=0.034), positive ß-hCG (32.3% and 21.8%; p=0.015) and clinical pregnancy (27.3% and 17.7%; p=0.018) rates were significantly higher in Group-I. No difference was observed between groups regarding the ongoing pregnancy rates (23.2% and 17.3%; p=0.143). CONCLUSION:Micronized progesterone vaginal capsule 600mg daily used for luteal support in the IVF/ICSI-ET cycles was observed to significantly increase the biochemical and clinical pregnancy rates compared to progesterone vaginal gel 180mg daily. However, no difference was observed between two groups regarding ongoing pregnancy rates.

STUDY QUESTION:Is oral dydrogesterone 30 mg daily (10 mg three times daily [TID]) non-inferior to micronized vaginal progesterone (MVP) 600 mg daily (200 mg TID) for luteal support in in vitro fertilization (IVF), assessed by the presence of fetal heartbeats determined by transvaginal ultrasound at 12 weeks of gestation? SUMMARY ANSWER:Non-inferiority of oral dydrogesterone versus MVP was demonstrated at 12 weeks of gestation, with a difference in pregnancy rate and an associated confidence interval (CI) that were both within the non-inferiority margin. WHAT IS KNOWN ALREADY:MVP is routinely used in most clinics for luteal support in IVF, but it is associated with side effects, such as vaginal irritation and discharge, as well as poor patient acceptance. Dydrogesterone may be an alternative treatment due to its patient-friendly oral administration. STUDY DESIGN, SIZE, DURATION:Lotus I was an international Phase III randomized controlled trial, performed across 38 sites, from August 2013 to March 2016. Subjects were premenopausal women (>18 to <42 years of age; body mass index (BMI) ≥18 to ≤30 kg/m2) with a documented history of infertility who were planning to undergo IVF. A centralized electronic system was used for randomization, and the study investigators, sponsor's study team, and subjects remained blinded throughout the study. PARTICIPANTS/MATERIALS, SETTING, METHODS:In total, 1031 subjects were randomized to receive either oral dydrogesterone (n = 520) or MVP (n = 511). Luteal support was started on the day of oocyte retrieval and continued until 12 weeks of gestation (Week 10), if a positive pregnancy test was obtained at 2 weeks after embryo transfer. MAIN RESULTS AND THE ROLE OF CHANCE:In the full analysis set (FAS), 497 and 477 subjects in the oral dydrogesterone and MVP groups, respectively, had an embryo transfer. Non-inferiority of oral dydrogesterone was demonstrated, with pregnancy rates at 12 weeks of gestation of 37.6% and 33.1% in the oral dydrogesterone and MVP treatment groups, respectively (difference 4.7%; 95% CI: -1.2-10.6%). Live birth rates of 34.6% (172 mothers with 213 newborns) and 29.8% (142 mothers with 158 newborns) were obtained in the dydrogesterone and MVP groups, respectively (difference 4.9%; 95% CI: -0.8-10.7%). Oral dydrogesterone was well tolerated and had a similar safety profile to MVP. LIMITATIONS, REASONS FOR CAUTION:The analysis of the results was powered to consider the clinical pregnancy rate, but the live birth rate may be of greater clinical interest. Conclusions relating to the differences between treatments in live birth rate, observed in this study, should therefore be made with caution. WIDER IMPLICATIONS OF THE FINDINGS:Oral dydrogesterone may replace MVP as the standard of care for luteal phase support in IVF, owing to the oral route being more patient-friendly than intravaginal administration, as well as it being a well tolerated and efficacious treatment. STUDY FUNDING/COMPETING INTEREST(S):Sponsored and supported by Abbott Established Pharmaceuticals Division. H.T.'s institution has received grants from Merck, MSD, Goodlife, Cook, Roche, Besins, Ferring and Mithra (now Allergan) and H.T. has received consultancy fees from Finox, Ferring, Abbott, ObsEva and Ovascience. G.S. has nothing to disclose. E.K. is an employee of Abbott GmbH. G.G. has received investigator fees from Abbott during the conduct of the study; outside of this submitted work, G.G. has received personal fees and non-financial support from MSD, Ferring, Merck-Serono, Finox, TEVA, Glycotope, as well as personal fees from VitroLife, NMC Healthcare LLC, ReprodWissen LLC and ZIVA LLC. TRIAL REGISTRATION NUMBER:NCT01850030 (clinicaltrials.gov). TRIAL REGISTRATION DATE:19 April 2013. DATE OF FIRST PATIENT'S ENROLLMENT:23 August 2013.

STUDY QUESTION:Is there a serum progesterone (P) threshold on the day of embryo transfer (ET) in artificial endometrium preparation cycles below which the chances of ongoing pregnancy are reduced? SUMMARY ANSWER:Serum P levels <8.8 ng/ml on the day of ET lower ongoing pregnancy rate (OPR) in both own or donated oocyte cycles. WHAT IS KNOWN ALREADY:We previously found that serum P levels <9.2 ng/ml on the day of ET significantly decrease OPR in a sample of 211 oocyte donation recipients. Here, we assessed whether these results are applicable to all infertile patients under an artificial endometrial preparation cycle, regardless of the oocyte origin. STUDY DESIGN, SIZE, DURATION:This prospective cohort study was performed between September 2017 and November 2018 and enrolled 1205 patients scheduled for ET after an artificial endometrial preparation cycle with estradiol valerate and micronized vaginal P (MVP, 400 mg twice daily). PARTICIPANTS/MATERIALS, SETTING, METHODS:Patients ≤50 years old with a triple-layer endometrium ≥6.5 mm underwent transfer of one or two blastocysts. A total of 1150 patients treated with own oocytes without preimplantation genetic testing for aneuploidies (PGT-A) (n = 184), own oocytes with PGT-A (n = 308) or donated oocytes (n = 658) were analyzed. The primary endpoint was the OPR beyond pregnancy week 12 based on serum P levels measured immediately before ET. MAIN RESULTS AND THE ROLE OF CHANCE:Women with serum P levels <8.8 ng/ml (30th percentile) had a significantly lower OPR (36.6% vs 54.4%) and live birth rate (35.5% vs 52.0%) than the rest of the patients. Multivariate logistic regression showed that serum P < 8.8 ng/ml was an independent factor influencing OPR in the overall population and in the three treatment groups. A significant negative correlation was observed between serum P levels and BMI, weight and time between the last P dose and blood tests and a positive correlation was found with age, height and number of days on HRT. Multivariate logistic regression showed that only body weight was an independent factor for presenting serum P levels <8.8 ng/ml. Obstetrical and perinatal outcomes did not differ in patients with ongoing pregnancy regardless of serum P levels being above/below 8.8 ng/ml. LIMITATIONS, REASONS FOR CAUTION:Only women with MVP were included. Extrapolation to other P administration forms needs to be validated. WIDER IMPLICATIONS OF THE FINDINGS:This study identified the threshold of serum P as 8.8 ng/ml on the day of ET for artificial endometrial preparation cycles necessary to optimize outcomes, in cycles with own or donated oocytes. One-third of patients receiving MVP show inadequate levels of serum P that, in turn, impact the success of the ART cycle. Monitoring P levels in the mid-luteal phase is recommended when using MVP to adjust the doses according to the needs of the patient. STUDY FUNDING/COMPETING INTEREST(S):None. TRIAL REGISTRATION NUMBER:NCT03272412.

Endometrium is the uterine lining that undergoes hundreds of cycles of proliferation, differentiation, and desquamation throughout a woman's reproductive life. Recently, much attention is paid to the appropriate endometrial functioning, as decreased endometrial receptivity is stated to be one of the concerns heavily influencing successes of embryo implantation rates and the efficacy of fertilization (IVF) treatment. In order to acquire and maintain the desired endometrial receptivity during IVF cycles, luteal phase support by various progestagens or other hormonal combinations is generally recommended. However, today, the selection of the specific hormonal therapy during IVF seems to be empirical, mainly due to a lack of appropriate tools for personalized approach. Here, we designed the genetic tool for patient-specific optimization of hormonal supplementation schemes required for the maintenance of endometrial receptivity during luteal phase. We optimized and characterized endometrial stromal cell (ESC) decidualization model as the adequate physiological reflection of endometrial sensitivity to steroid hormones. Based on the whole transcriptome RNA sequencing and the corresponding bioinformatics, we proposed that activation of the decidual prolactin (PRL) promoter containing ancient transposons MER20 and MER39 may reflect functioning of the core decidual regulatory network. Furthermore, we cloned the sequence of decidual PRL promoter containing MER20 and part of MER39 into the expression vector to estimate the effectiveness of ESC decidual response and verified sensitivity of the designed system. We additionally confirmed specificity of the generated tool using human diploid fibroblasts and adipose-derived human mesenchymal stem cells. Finally, we demonstrated the possibility to apply our tool for personalized hormone screening by comparing the effects of natural progesterone and three synthetic analogs (medroxyprogesterone 17-acetate, 17α-hydroxyprogesterone caproate, dydrogesterone) on decidualization of six ESC lines obtained from patients planning to undergo the IVF procedure. To sum up, we developed the "all-in-one" genetic tool based on the MER20/MER39 expression cassette that provides the ability to predict the most appropriate hormonal cocktail for endometrial receptivity maintenance specifically and safely for the patient, and thus to define the personal treatment strategy prior to the IVF procedure.

Oral dydrogesterone has been used for luteal phase support on an empirical basis since the early days of in vitro fertilization (IVF) treatment. Systematic comparisons of oral dydrogesterone with vaginal progesterone, so far considered to be the standard of care, started to appear in the middle 2000s. Recently, a large, randomized, double-blind, double-dummy phase III trial on the use of daily 30 mg oral dydrogesterone versus daily 600 mg micronized vaginal progesterone for LPS in IVF was published. This company-sponsored trial confirmed the efficacy findings from previous independent researchers and firmly established the noninferiority of daily 30 mg oral dydrogesterone for luteal phase support. Despite oral administration and first pass through the liver, dydrogesterone was as well tolerated as vaginal progesterone in safety analyses. Moreover, no new fetal safety concerns have arisen from that trial. Given the widespread preference of women for an oral compound, dydrogesterone may well become the new standard for luteal phase support in fresh embryo transfer IVF cycles.

OBJECTIVE:To assess patient experience and convenience of using progesterone vaginal ring (VR) versus vaginal gel for women requiring luteal phase support during in vitro fertilization (IVF). DESIGN:Post hoc analysis of a prospective, randomized, single-blind, multicenter, phase 3 clinical trial. SETTING:Twenty-two U.S. IVF centers. PATIENT(S):Women undergoing IVF (N = 1,297). INTERVENTION(S):Randomization to weekly VR or daily gel the day after egg retrieval for up to 10 weeks, with fresh embryo transfer IVF per site-specific procedures. MAIN OUTCOME MEASURE(S):Patient satisfaction questionnaire completed at final study visit. RESULT(S):In the women who were taking ≥1 dose of either VR (n = 647) or gel (n = 650), >97% reported that learning to use the formulation, remembering to take it at the correct time, and using it as prescribed was "easy" or "somewhat easy." More VR than gel users reported noninterference with daily activity (93.3% vs. 74.7%, P<.001), sexual comfort (80.3% vs. 67.8%, P<.001), and sexual desire (73.8% vs. 61.8%, P<.001), as well as not being bothered during sexual intercourse (66.9% vs. 39.2%, P<.001). More gel than VR users reported no difficulty with application (97.4% vs. 80.9%, P<.001). Among women who had previously used progesterone during IVF, more VR users than gel users preferred their currently assigned treatment to their previous treatment (91.4% vs. 83.0%, P=.03). CONCLUSION(S):Weekly progesterone VR and daily progesterone gel were easy to use, with limited impact on quality of life. Overall, the VR appeared to interfere less with daily life, social activities, and sexual activity although the gel was less difficult or stressful to apply. CLINICAL TRIAL REGISTRATION NUMBER:NCT00615251.

BACKGROUND AND OBJECTIVE:Luteal phase physiology is distorted by in vitro fertilization (IVF) cycles using gonadotropin-releasing hormone (GnRH) agonists and antagonists, Controlled ovarian hyperstimulation leads to luteal phase defect and for this reason, luteal phase support is now an integral part of IVF/ICSI-ET programs. The support is provided by hCG, progesterone or GnRH-a. This study compared the efficiency, safety and tolerance of two vaginal micronized progesterones, Utrogestan and Crinone 8%. METHODS:111 women, 18-40 years old, FSH < 10 IU/L and normal uterus findings were included. The efficiency of the two preparations to provide luteal support was evaluated by the fertilization, implantation, pregnancy and take-home baby rates. The safety was compared through the results of vaginal findings and vaginal inflammation markers before and after treatment. Comparison of tolerance was made by evaluating 21 subjective patient questionnaire parameters. RESULTS:There were no significant differences between the preparations in terms of efficiency or safety though Crinone 8% was better tolerated. CONCLUSION:The outcomes of this study suggest that a vaginal gel with micronized progesterone (Crinone 8%) is the optimal choice at this time for luteal support.

Nearly 5 million babies have been delivered following assisted conception (IVF/ICSI) and the demand is increasing. Meticulous ovarian stimulation and well programmed luteal phase support are the landmarks of treatment success. Although the importance of luteal phase support in IVF/ICSI cycles is well established, the optimal route, dose and duration of this support is still a matter of debate. Regardless of the ovarian stimulation, parenteral and vaginal progesterone has been one of the most common routes. However, oral or subcutaneous routes are also well-investigated and reveal satisfactory clinical outcomes. It is obviously critical to choose a progesterone with adequate clinical efficacy and patient tolerability as well. Moreover, fresh and frozen embryo transfer cycles markedly different from each other in terms of physiological changes and luteal support concept should be modified accordingly. The aim of this narrative review is to provide evidence-based take home messages for the luteal phase support in either fresh or frozen embryo transfer cycles in the context of a recent scientific evidence.

RESEARCH QUESTION:What are the safety and feasibility of repeated subcutaneous doses of gonadotrophin-releasing hormone (GnRH) agonist for luteal support in IVF cycles triggered by a GnRH agonist? DESIGN:In this prospective trial, patients exhibiting oestradiol concentrations of over 2500 pg/ml after use of a GnRH agonist for triggering ovulation were initially randomized to GnRH agonist luteal support (0.1 mg subcutaneously every other day, starting on day 3 after embryo transfer) or to a control group supported by 80 µg of recombinant human chorionic gonadotrophin (HCG) on day 3 after embryo transfer. All patients underwent a day 5 blastocyst transfer. Randomization to the HCG luteal support was stopped owing to two cases of ovarian hyperstimulation syndrome (OHSS) and the study was continued solely with GnRH agonist luteal support. RESULTS:The study included 39 women in the repeated GnRH agonist luteal support group and seven in the HCG micro dose group. There were no cases of OHSS among patients supported by a GnRH agonist, and no other adverse events were recorded. There were no cases of bleeding before the pregnancy test, and hence no cases of an insufficient luteal phase. A clinical pregnancy rate of 43.6% was achieved with GnRH agonist luteal support. Hormone dynamics during the stimulation cycle reflected rising LH and progesterone concentrations after the introduction of GnRH agonist support. CONCLUSIONS:Repeated doses of GnRH agonist every other day as a method of luteal support provided safe and effective luteal support for women who underwent GnRH agonist triggering in a GnRH antagonist IVF cycle.

We evaluated the effect of combined use of oral oestrogen (E2) and vaginal progesterone (P) to support luteal phase in antagonist intracytoplasmic sperm injection (ICSI) cycles. We analysed data from 176 patients who underwent ICSI cycles with antagonist protocol. P 90 mg vaginal gel once a day and micronised E2 of 4 mg/day, were started from the day of oocyte pick up and continued to the 12th day of embryo transfer. Group 1 ( = 79) patients received E2 + P for luteal phase support. In group 2 ( = 97) patients, only P 90 mg vaginal gel was used for luteal phase support. There were no significant differences between group 1 and group 2 patients in terms of clinical pregnancy rates (PRs) (26.58% vs. 20.62%,  = .352), early pregnancy loss rates (6.33% vs. 6.19%,  = .969), incidence of luteal vaginal bleeding (8.86% vs. 8.25%,  = .885) and implantation rates (22.8% vs. 16.9%,  = .298). In conclusion, our study showed no beneficial effect of addition of E2 to luteal phase support on clinical PR in antagonist IVF cycles.Impact statement Luteal phase deficiency is defined as a disruption in progesterone and oestrogen production after ovulation. It is clear that, luteal phase supplementation to improve the outcomes in fertilisation (IVF) cycles is mandatory. As an iatrogenic complication of assisted reproductive technique, decreased luteal oestrogen and progesterone levels lead to decreased pregnancy rates (PRs) and implantation rates. In this study, we aimed to present the role of luteal phase oestrogen administration in GnRH antagonist cycles. A total of 176 cases received progesterone vaginal gel form for luteal phase support. Study group received 4 mg oral oestradiol hemihydrate in addition to progesterone. Compared to previous studies, our study consisted of larger number of patients and we used oestradiol through oral route. We found out that luteal oestradiol support did not improve the clinical PR. Our study showed no beneficial effect of addition of oestradiol to luteal phase support on clinical PR in antagonist IVF cycles.

The aim of this systematic review and meta-analysis was to conduct a comprehensive assessment of the evidence on the efficacy and safety of oral dydrogesterone versus micronized vaginal progesterone (MVP) for luteal phase support. Embase and MEDLINE were searched for studies that evaluated the effect of luteal phase support with daily administration of oral dydrogesterone (20 to 40 mg) versus MVP capsules (600 to 800 mg) or gel (90 mg) on pregnancy or live birth rates in women undergoing fresh-cycle IVF (protocol registered at PROSPERO [CRD42018105949]). Individual participant data (IPD) were extracted for the primary analysis where available and aggregate data were extracted for the secondary analysis. Nine studies were eligible for inclusion; two studies had suitable IPD (full analysis sample: n = 1957). In the meta-analysis of IPD, oral dydrogesterone was associated with a significantly higher chance of ongoing pregnancy at 12 weeks of gestation (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.08 to 1.61; P = 0.0075) and live birth (OR, 1.28; 95% CI, 1.04 to 1.57; P = 0.0214) compared to MVP. A meta-analysis combining IPD and aggregate data for all nine studies also demonstrated a statistically significant difference between oral dydrogesterone and MVP (pregnancy: OR, 1.16; 95% CI, 1.01 to 1.34; P = 0.04; live birth: OR, 1.19; 95% CI, 1.03 to 1.38; P = 0.02). Safety parameters were similar between the two groups. Collectively, this study indicates that a higher pregnancy rate and live birth rate may be obtained in women receiving oral dydrogesterone versus MVP for luteal phase support.

OBJECTIVE:The use of gonadotropin-releasing hormone agonist for ovulation triggering has become an intriguing topic in the last few years. As long as adequate luteal phase support is provided, it may be a valuable alternative to standard hCG triggering, associated with a significant reduction in OHSS incidence. Several luteal phase support options have been proposed, but few studies have addressed the issue of the appropriate route for progesterone administration to women triggered with GnRHa. The aim of the study was to evaluate the effect of GnRHa triggering on IVF/ICSI outcomes, using modified luteal phase support with intramuscular progesterone. PATIENTS AND METHODS:A retrospective study was carried out between January 2014 and December 2015, comparing the reproductive outcome in GnRHa triggered women given modified luteal phase support with intramuscular progesterone (Group A) with the outcome in women triggered with standard hCG (Group B) in IVF/ICSI cycles. RESULTS:200 (Group A n = 100; Group B n = 100) consecutive normoresponder women were included. No differences with respect to Age, BMI, basal FSH, basal Estradiol and infertility diagnosis were observed between groups. Increased numbers of retrieved oocytes (8.1 ± 3.3 versus 6.8 ± 3.5, p = 0.009) and mature oocytes (5.8 ± 2.6 versus 5.1 ± 2.7, p = 0.03) were detected in Group A compared with Group B. Implantation, biochemical pregnancy and ongoing pregnancy rates were similar. CONCLUSIONS:Our findings confirmed that the GnRHa triggering strategy is associated with increased number of oocytes retrieved and of mature oocytes even in normoresponder women. Moreover, in these patients, the use of intramuscular progesterone during luteal phase support achieved satisfactory IVF outcomes.

This review and meta-analysis aim to assess the effect of prolonged progesterone support on pregnancy outcomes in women undergoing fresh embryo transfer after IVF/intracytoplasmic sperm injection (ICSI). Two independent authors searched Embase, MEDLINE and grey literature from inception to January 2019 for randomized controlled trials (RCT) of prolonged progesterone support versus early cessation. Risk of bias was assessed. Outcome measures were live birth, miscarriage and ongoing pregnancy rate. The study was registered with PROSPERO (CRD42018088605). Seven trials involving 1627 participants were included: three reported live birth rate (672/830), seven the miscarriage rate (178/1627) and seven the ongoing pregnancy rate (1351/1627). Clinical outcomes were similar between early progesterone cessation versus progesterone continuation: live birth rate (risk ratio [RR] 0.94, 95% confidence interval [CI] 0.88-1.00), miscarriage rate (RR 0.91, 95% CI 0.69-1.20) and ongoing pregnancy rate (RR 0.98, 95% CI 0.91-1.05). Ongoing pregnancy rates were similar when analyses were restricted to those with cessation of progesterone on the day of a positive human chorionic gonadotrophin (RR 0.93, 95% CI 0.83-1.06). This meta-analysis suggests that prolonged progesterone support may be unnecessary after fresh embryo transfer. Further larger RCT would be useful to corroborate and lead to standardized duration of progesterone luteal phase support across IVF/ICSI centres.

This is a pilot study performed in a private IVF unit. The objective of the study was to investigate whether luteal support is required in IVF cycles after mild stimulation with clomiphene citrate and low FSH doses. The study included 15 patients with good prognosis (defined as ≤38 years old with normal ovarian reserve and normovulatory cycles, body mass index <29 kg/m, no previous cycles, no severe endometriosis, no history of recurrent miscarriage, no endocrine/autoimmune diseases and no surgical semen extraction from the partner) undergoing IVF with mild stimulation. Patients were monitored during the luteal phase by serum progesterone and LH. The luteal support was started only when necessary. No patient needed luteal phase support because the resultant steroid environment was different from that associated with conventional stimulation techniques. The live birth rate was 40% (6/15) and the implantation rate 30% (6/20). There are several benefits to mild stimulation, including low cost, less patient distress and improved endometrial receptivity. Our study supports the concept that mild stimulation may have an additional benefit during the luteal phase, by obviating the need for luteal phase support.

Luteal phase support (LPS) in assisted reproduction cycles has been widely investigated in recent years. Although progesterone represents the preferential product for luteal phase supplementation in cycles with fresh embryo transfer, there is ongoing debate as to when to start, which is the best route, dosage and duration, and whether there is a place for additional agents. Nevertheless, fertility specialists do not always adhere to evidence-based recommendations in their clinical practice. The aim of this worldwide web-based survey is to document the currently used protocols for luteal phase support and appraisal tendencies of drug prescription behavior and to compare these to the existing evidence-based literature. A questionnaire was developed and sent by secure e-mail to 1,480 clinicians involved in ART worldwide. One hundred and forty-eighth clinicians from 34 countries returned completed questionnaires. Progesterone support is usually started on the day of oocyte retrieval. Eighty percent of clinicians applied the administration of vaginal progesterone only. Intramuscular progesterone was prescribed by 6%, while oral progestin or subcutaneous progesterone were each prescribed by 5% of clinicians, respectively. Progesterone was administered until 8-10 weeks' gestation by 35% and 12 weeks by 52% of respondents. Vaginal administration was the preferred route for luteal phase support. The reported emerging use of the oral route confirms the expected shift in clinical practice as a result of recent evidence showing a reassuring safety score of oral progestins. In spite of the lack of evidence supporting the continuation of luteal support until 12 weeks' gestation, this practice was adhered to by more than half of the clinicians surveyed, highlighting the difference between evidence-based medicine and real-life practices.

STUDY QUESTION:Is the chance of a live birth following IVF treatment and fresh embryo transfer affected by early and mid-luteal serum progesterone (P4) levels? SUMMARY ANSWER:Low as well as high serum P4 levels in the early and mid-luteal phase reduce the chance of a live birth following IVF treatment with fresh embryo transfer. WHAT IS KNOWN ALREADY:Data from non-human studies and studies of frozen-thawed embryo transfer cycles indicate that low as well as high P4 levels during the mid-luteal phase decrease the chance of pregnancy. The altered P4 pattern may disrupt the endometrial maturation leading to asynchrony between embryonic development and endometrial receptivity, thereby, compromising implantation and early development of pregnancy. STUDY DESIGN, SIZE, DURATION:Prospective multicenter cohort study of 602 women undergoing IVF treatment. Patients were recruited from four Danish public Fertility Centers from May 2014 to June 2017. The study population was unselected, thus, representing a normal everyday patient cohort. Patients were treated in a long GnRH-agonist protocol or a GnRH-antagonist protocol and triggered for final oocyte maturation with either hCG or a GnRH-agonist. The same vaginal luteal support regimen was applied in all patients. PARTICIPANTS/MATERIALS, SETTING, METHODS:Serum P4 levels from the early or mid-luteal phase were correlated to positive hCG and live birth rates (delivery > gestational week 20). Patients were divided into four P4 groups based on raw data of P4 serum levels and reproductive outcomes during early luteal phase (P4<60 nmol/l, P4 60-100 nmol/l, P4 101-400 nmol/l and P4>400 nmol/l) and during mid-luteal phase (P4<150 nmol/l, P4 150-250 nmol/l, P4 251-400 nmol/l and P4>400 nmol/l). MAIN RESULTS AND THE ROLE OF CHANCE:The optimal chance of pregnancy was achieved with serum P4 levels of 60-100 nmol/l in the early luteal phase whereas the optimal P4 level during the mid-luteal phase was 150-250 nmol/l. Below, but most distinctly above these levels, the chance of pregnancy was consistently reduced. With an early luteal P4 level of 60-100 nmol/l, the chance of a positive hCG-test was 73%, 95% CI: [59, 84] following cleavage stage embryo transfer. In contrast, with P4 levels >400 nmol/l, the chance of a positive hCG-test was significantly reduced to 35%, 95% CI: [17, 57], thus, an absolute risk difference of -38%, P = 0.01. A similar negative association between early luteal P4 and live birth rate was found, although it did not reach statistical significance. During the mid-luteal phase, a P4 level of 150-250 nmol/l resulted in an optimal chance of live birth: 54%, 95% CI: [37, 70] compared to 38%, 95% CI: [20, 60] with a P4 level >400 nmol/l, thus, an absolute risk difference of -16%, P = 0.14. All estimates were adjusted for maternal age, maternal BMI, study site, final follicle count and late follicular P4 levels. LIMITATIONS, REASONS FOR CAUTION:This study is the first to explore the possible upper and lower thresholds for luteal P4 following IVF treatment and fresh embryo transfer, and the optimal P4 ranges found in this study should be corroborated in future clinical trials. Furthermore, the P4 thresholds in this study only apply to fresh IVF cycles, using vaginal luteal phase support, as the optimal P4 level in cycles using intramuscular P4 may be different. WIDER IMPLICATIONS OF THE FINDINGS:Future studies are necessary to explore whether additional exogenous luteal P4 supplementation in the low P4 group could increase the chance of a live birth following fresh embryo transfer, and whether patients with luteal P4 levels >400 nmol/l would benefit from segmentation followed by subsequent transfer in frozen/thawed cycles. TRIAL REGISTRATION NUMBER:NCT02129998 (Clinicaltrials.gov). STUDY FUNDING/COMPETING INTEREST(S):L.H.T. received an unrestricted grant from Ferring Pharmaceuticals, Denmark, to support this study. P.H. received unrestricted research grants from MSD, Merck, Gedeon Richter and Ferring Pharmaceuticals outside of this work as well as honoraria for lectures from MSD, Merck and Gedeon Richter outside of this work. U.K. received honoraria for lectures from MSD and Ferring Pharmaceuticals outside of this work. C.A. received unrestricted research grants from MSD, IBSA, and Ferring Pharmaceuticals outside of this work as well as honoraria for lectures from MSD and IBSA. H.O.E. and B.B.P. received an unrestricted research grant from Gedeon Richter outside of this work. K.E., L.B., D.P. and B.H. have no conflict of interest. Furthermore, grants from 'The Health Research Fund of Central Denmark Region', 'The Research Foundation of the Hospital of Central Jutland', 'The Research Foundation of A.P. Møller', 'The Research Foundation of Aase & Ejnar Danielsen', 'The Research Foundation of Dagmar Marshall', 'The Research Foundation of Dir. Jacob Madsen & Hustru Olga Madsen', 'The Research Foundation of Fam. Hede Nielsen' and 'The Danish Medical Research Grant' supported conducting this study. The providers of funding were neither involved in the conduction of the study nor in the writing of the scientific report.

STUDY QUESTION:Are there any differences in the molecular characteristics of the luteal granulosa cells (GC) obtained from stimulated versus non-stimulated (natural) IVF cycles that may help explain the defective luteal phase in the former? SUMMARY ANSWER:Luteal GC of stimulated IVF cycles, particularly those of agonist-triggered antagonist cycles, are less viable ex vivo, express LH receptor and anti-apoptotic genes at lower levels, undergo apoptosis earlier and fail to maintain their estradiol (E2) and progesterone (P4) production in comparison to natural cycle GC. WHAT IS KNOWN ALREADY:Luteal function is defective in stimulated IVF cycles, which necessitates P4 and/or hCG administration (known as luteal phase support) in order to improve clinical pregnancy rates and prevent miscarriage. The luteal phase becomes shorter and menstruation begins earlier than a natural cycle if a pregnancy cannot be achieved, indicative of early demise of corpus luteum (premature luteolysis). Supra-physiological levels of steroids produced by multiple corpora luteae in the stimulated IVF cycles are believed to inhibit LH release directly via negative feedback actions on the hypothalamic-pituitary-ovarian axis resulting in low circulating levels of LH and a defective luteal phase. We hypothesized that some defects in the viability and steroidogenic activity of the luteal GC of the stimulated IVF cycles might contribute to this defective luteal phase in comparison to natural cycle GC. This issue has not been studied in human before. STUDY DESIGN, SIZE, DURATION:A comparative translational research study of ex vivo and in vitro models of luteal GC recovered from IVF patients undergoing natural versus stimulated IVF cycles was carried out. Luteinized GC were obtained from 154 IVF patients undergoing either natural (n = 22) or stimulated IVF cycles with recombinant FSH and GnRH agonist (long) (n = 44), or antagonist protocol triggered conventionally either with recombinant hCG (n = 46) or with a GnRH agonist (n = 42). GC were maintained in vitro for up to 6 days. PARTICIPANTS/MATERIALS, SETTING, METHODS:Cellular viability (YO-PRO-1 staining), the expression of the steroidogenic enzymes, pro-apoptotic genes [Bcl-2-associated death promoter (BAD), Bcl-2-associated X protein (BAX) and Caspase-3 (CASP3)], anti-apoptotic genes [RAC-alpha serine/threonine-protein kinase (AKT-1) and Bcl-2-like protein 2 (BCL2-L2)], LH receptor, vascular endothelial growth factor (VEGF) (using real-time quantitative PCR at mRNA level and western blot immunoprecipitation assay at protein level) and in vitro E2 and P4 production (electrochemiluminescence immunoassay) were compared in GC among the groups. MAIN RESULTS AND THE ROLE OF CHANCE:Natural cycle GC were significantly more viable ex vivo (88%) compared to their counterparts of the stimulated IVF cycles (66, 64 and 37% for agonist and antagonist cycles triggered with hCG and GnRH agonist respectively, P < 0.01). They were also more capable of maintaining their vitality in culture compared to their counterparts from the stimulated IVF cycles: at the end of the 6-day culture period, 74% of the cells were still viable whereas only 48, 43 and 22% of the cells from the agonist and antagonist cycles triggered with hCG and agonist respectively, were viable (P < 0.01). The mRNA expression of anti-apoptotic genes (AKT-1 and BCL2-L2) was significantly lower, while that of pro-apoptotic genes (BAD, BAX and CASP3) was significantly higher in the stimulated cycles, particularly in the agonist-triggered antagonist cycles, compared to natural cycle GC (P < 0.01 for long protocol and antagonist hCG trigger, P < 0.001 for agonist trigger). The expression of steroidogenic enzymes (stAR, SCC, 3β-HSD and aromatase) and VEGF was significantly higher in the agonist and hCG-triggered antagonist cycles compared to natural cycle GC. Therefore, in vitro E2 and P4 production in cells from the stimulated IVF cycles was significantly higher than their counterparts obtained from the natural cycles in the first 2 days of culture. However, after Day 2, their viability and hormone production began to decline very rapidly with the most drastic decrease being observed in the agonist-triggered cycles. By contrast, natural cycle GC maintained their viability and produced E2 and P4 in increasing amounts in culture up to 6 days. In vitro P production and the mRNA and protein expression of LH receptor, VEGF and 3β-HSD were most defective in the agonist-triggered antagonist cycles compared to natural and agonist and hCG-triggered antagonist cycles. In vitro hCG treatment of a subset of the cells from the agonist-triggered cycles improved their viability, increased E2 and P4 production in vitro and up-regulated the mRNA expression of anti-apoptotic gene BCL-L2 together with steroidogenic enzymes stAR, SCC, 3B-HSD, LH receptor and VEGF. LARGE SCALE DATA:Not applicable. LIMITATIONS, REASONS FOR CAUTION:The limitations include analysis of luteinized GC only might not reflect the in vivo mechanisms involved in survival and function of the whole corpus luteum; GC recovered during oocyte retrieval belong to a very early stage of the luteal phase and might not be representative; effects of ovulation triggered with hCG may not equate to the endogenous LH trigger; the clinical characteristics of the patients may vary among the different groups and it was not possible to correlate stimulation-related molecular alterations in luteal GC with the clinical outcome, as no oocytes have been utilized yet. Therefore, our findings do not conclusively rule out the possibility that some other mechanisms in vivo may also account for defective luteal function observed in stimulated IVF cycles. WIDER IMPLICATIONS OF THE FINDINGS:Ovarian stimulation is associated with significant alterations in the viability and steroidogenic activity of luteal GC depending on the stimulation protocol and mode of ovulation trigger. Reduced survival and down-regulated expression of 3B-HSD, LH receptor and VEGF leading to compromised steroid production in stimulated cycles, and particularly in the agonist-triggered cycles, may at least in part help explain why the luteal phase is defective and requires exogenous support in these cycles. STUDY FUNDING/COMPETING INTEREST(S):This study was funded by the School of Medicine, the Graduate School of Health Sciences of Koc University and Koç University Research Center for Translational Medicine (KUTTAM), equally funded by the Republic of Turkey Ministry of Development Research Infrastructure Support Program. All authors declare no conflict of interest.

The aim of this study was to evaluate the reproductive outcome in patients receiving frozen-thawed embryo transfer before and after doubling of the vaginal progesterone gel supplementation. The study was a retrospective study performed in The Fertility Clinic, Skive Regional Hospital, Denmark. A total of 346 infertility patients with oligoamenorrhoea undergoing frozen-thawed embryo transfer after priming with oestradiol and vaginal progesterone gel were included. The vaginal progesterone dose was changed from 90 mg (Crinone) once a day to twice a day and the reproductive outcome during the two periods was compared. The pregnancy rate increased significantly after doubling of the progesterone dose (26.7% (90 mg) versus 38.4% (180 mg); P=0.021). Moreover, the early pregnancy loss rate decreased significantly (67.4% versus 43.7%, respectively; P=0.014), which significantly increased the delivery rate (8.7% versus 20.5%, respectively; P=0.002). Doubling of the vaginal progesterone gel supplementation during frozen-thawed embryo transfer cycles decreased the early pregnancy loss rate, resulting in a significantly higher delivery rate. This study evaluated the reproductive outcome of 346 women with oligoamenorrhoea (cycle length >34 days) or amenorrhoea undergoing oestradiol and progesterone priming prior to frozen-thawed embryo transfer. Patients treated with vaginal progesterone gel (Crinone 90 mg) twice daily had a lower risk of pregnancy loss (43.7%) compared with women treated once a day (67.4%). This resulted in a significantly higher delivery rate (20.5% versus 8.7%, respectively).

BACKGROUND:The optimal route of progesterone administration for luteal support in cryopreserved embryo transfer (CET) has been the subject of much debate. While most published research has pertained to day 3 transfers, recent data on blastocyst CET has suggested that intramuscular progesterone (IMP) is superior to twice daily vaginal Endometrin suppositories for luteal phase support, resulting in significantly higher ongoing pregnancy rates. This study aimed to determine whether IMP is similarly superior to 8% Crinone vaginal gel for luteal phase support following blastocyst CET. METHODS:Autologous and donor oocyte blastocyst cryopreserved single embryo transfer (SET) cycles from January 2014-January 2019 utilizing either 50 mg IMP daily or 90 mg 8% Crinone gel twice daily for luteal support were included. The primary outcome was live birth. Secondary outcomes included biochemical pregnancy, spontaneous abortion, and clinical pregnancy. All analyses were adjusted a priori for oocyte age. Log-binomial regression analysis was performed with differences in outcomes reported as relative risk (RR) with 95% confidence intervals (CI). RESULTS:A total of 1710 cycles were included, of which 1594 utilized IMP and 116 utilized 8% Crinone gel. Demographic and cycles characteristics were similar between the two groups. Compared to cycles utilizing IMP, cycles utilizing Crinone gel resulted in similar rates of live birth (RR 0.91; 95% CI 0.73-1.13), biochemical pregnancy (RR 1.12, 95% CI 0.65-1.92), spontaneous abortion (RR 1.41, 95% CI 0.90-2.20), and clinical pregnancy (RR 1.00, 95% CI 0.86-1.17). CONCLUSIONS:Compared to cryopreserved blastocyst SET cycles utilizing IMP for luteal support, cycles utilizing 8% Crinone gel resulted in similar likelihood of live birth.

STUDY QUESTION:Are progesterone vaginal pessaries 400 mg twice a day (bid) non-inferior to progesterone vaginal gel (90 mg) once a day (od) in the primary endpoint of clinical pregnancy rate after 38 days of luteal phase support in women undergoing in vitro fertilisation (IVF)? SUMMARY ANSWER:Non-inferiority of progesterone vaginal pessaries 400 mg bid to progesterone 8% vaginal gel (90 mg od) was shown for clinical pregnancy rate after 38 days of luteal phase support. WHAT IS KNOWN ALREADY:To maximise successful embryo transfer after IVF, additionally administered progesterone is used for proper endometrium transformation in the luteal phase. Vaginally administered progesterone results in adequate secretory transformation of the endometrium. STUDY DESIGN, SIZE, DURATION:This multicentre, multinational, open, randomised, two-parallel group, non-inferiority Phase 3 clinical trial was carried out at 17 study sites in five European countries (Belgium, Bulgaria, Czech Republic, Hungary and Serbia) between October 2013 and August 2014. An interactive web response system (IWRS) was implemented for treatment allocation at the sites. Power analysis, based on the assumptions of a non-inferiority margin of -9%, a significance level of α 2.5% (one-sided), power 90%, at a reference pregnancy rate for the progesterone vaginal gel group of 30%, as well as applying a dropout rate of 10%, yielded a total number of 766 patients to be randomised. PARTICIPANTS/MATERIALS, SETTING, METHODS:Women aged between 18 and 40 years with a clinical indication for IVF/intracytoplasmic sperm injection (ICSI) and embryo transfer were eligible to participate. The clinical pregnancy rate was assessed by fetal heart movement measured by transvaginal ultrasound at day 38 (D38) (primary endpoint) and D70. Also assessed were biochemical pregnancy rate (assessed by serum β-hCG ≥25 IU/L), clinical implantation rates at D38, patient evaluation of vaginal bleeding and discharge (assessed by diary) and adverse event (AE) incidence, severity and relationship to study medication. MAIN RESULTS AND THE ROLE OF CHANCE:A total of 769 female patients were randomised to progesterone 400 mg vaginal pessaries bid (n = 385, 50.1%) or progesterone 90 mg vaginal gel od (n = 384, 49.9%). Patients receiving progesterone vaginal pessaries and progesterone vaginal gel were comparable in demographics, baseline characteristics and number of retrieved oocytes. In the full analysis set (FAS; n = 369 progesterone vaginal pessaries and n = 368 progesterone vaginal gel), clinical pregnancy rates on D38 were 38.3% for progesterone vaginal pessaries and 39.9% for progesterone vaginal gel. In the per protocol analysis set (PP; n = 357 progesterone vaginal pessaries and n = 356 progesterone vaginal gel), clinical pregnancy rates on D38 were 38.1% for progesterone vaginal pessaries and 40.4% for progesterone vaginal gel. For the differences in pregnancy rates between the progesterone vaginal pessaries group and the progesterone vaginal gel, the lower limit of the 97.5% CI was -8.6 and -9.5% for the FAS and PP datasets, respectively. The original prespecified non-inferiority margin of -9% was thus met in the FAS dataset but was marginally below this in the PP dataset. However, the pregnancy rate of the comparator was higher than the anticipated rate of 30%, and a predetermined logistic regression model including treatment group, country and age group effects without interaction terms showed non-inferiority of progesterone vaginal pessaries to progesterone vaginal gel for both the FAS and PP populations, in that the lower limits of the 95% CIs were above 0.7 for both analyses. As a result of this, the relevant authorities accepted to widen the acceptable non-inferiority margin to -10%, and as such both the FAS and PP populations succeeded in showing non-inferiority. Biochemical pregnancy and clinical implantation rates were comparable for both treatments. Both treatment groups showed similar high compliance throughout the study, and the safety profiles were also comparable between the groups. Drug-related AEs occurred with frequencies of 15.1% with progesterone vaginal pessaries and 14.4% with progesterone vaginal gel. LIMITATIONS, REASONS FOR CAUTION:Clinical pregnancy rate is a surrogate for the outcome of live birth rate. WIDER IMPLICATIONS OF THE FINDINGS:Progesterone 400 mg pessaries bid for luteal phase support is an effective, safe and tolerable treatment option for women undergoing IVF during ART. STUDY FUNDING/COMPETING INTEREST(S):This work was funded by Actavis Group PTC ehf., Iceland, part of Teva Pharmaceuticals, and by L.D. Collins & Co. Ltd. Gedeon Richter plc has recently entered into a license and distribution agreement to commercialise the vaginal pessaries in the European Union (except Ireland/UK). The progesterone vaginal pessaries studied are now marketed as Cyclogest®, Amelgen®, Cyclovita®, Luteum and Cygest® throughout the EU, Asia and Middle East & North Africa. The competing interests are as follows. H.S.: employee of Gedeon Richter plc/PregLem S.A. C.K.: consultant to L.D. Collins & Co. Ltd and received consulting fees for work performed. T.D.H.: at the initiation and completion of this study, full professor at KU Leuven and Head of Leuven University Fertility Center at the University Hospital Gasthuisberg, Leuven, Belgium. In October 2015, T.D.H. became vice president of Global Medical Affairs Fertility at the pharmaceutical company Merck-marketing authorisation holder of the Progesterone vaginal gel (Crinone®)-and has remained a part-time professor at KU Leuven (Belgium) and adjunct professor at Yale University (New Haven, CT, USA). T.B.M.: at the initiation and completion of this study, employee of Actavis Group PTC ehf. I.K.: consultant to Actavis, later TEVA and received consulting fees for work performed. S.H.: at the initiation and completion of this study, employee of Actavis Group PTC ehf. TRIAL REGISTRATION NUMBER:EudraCT number 2013-001105-81. TRIAL REGISTRATION DATE:2 July 2013. DATE OF FIRST PATIENT’S ENROLMENT:9 October 2013.

STUDY QUESTION:Which progesterone vaginal pessary dose regimen induces adequate secretory transformation of the endometrium, in comparison with progesterone vaginal gel and placebo? SUMMARY ANSWER:The best secretory transformation of the endometrium was observed during treatment with 400 mg progesterone vaginal pessaries, administered twice daily. WHAT IS KNOWN ALREADY:Vaginally administered progesterone is widely used for luteal phase support (LPS) in assisted reproductive techniques (ART). Although several vaginal formulations using various doses are available, little is known on the impact of formulation and doses at the endometrial level. STUDY DESIGN, SIZE, DURATION:The study had a randomised, observer-blind design and comprised two parts. The participants used study medication during two or three treatment periods, separated by washout periods. Subjects in Part 1 (n = 61 treated) received 200 mg progesterone vaginal pessaries twice daily (bid), 400 mg pessaries bid and the comparator 90 mg progesterone vaginal gel once daily (od) in a 3-way crossover design. Subjects in Part 2 (n = 64 treated) received 100 mg pessaries bid in one period and 400 mg pessaries od in the other period in a 2-way crossover design. A subgroup of these subjects (n = 22 treated) received placebo vaginal pessaries bid in a third period in a non-randomised manner. The study was performed from May 2012 until April 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS:The study was performed at a clinical research centre in healthy female volunteers of reproductive age. The subjects used 2 mg estradiol bid for 24 days in each treatment cycle. Progesterone or placebo was administered vaginally from Day 15 onwards during 10 days. In each treatment period, an endometrial biopsy for histological evaluation was performed on Day 23 and pharmacokinetic parameters were determined after the first progesterone dose on Day 15 and after the last dose on Day 24. MAIN RESULTS AND THE ROLE OF CHANCE:Frequencies of (early and late) secretory transformation of the endometrium, i.e. adequate responses, during treatment with 200 mg and 400 mg vaginal pessaries bid were comparable with those during 90 mg vaginal gel treatment (90-94%), whereas lower secretory transformation rates were observed during treatment with 100 mg bid and 400 mg od (64-75%). At the time of the endometrial biopsy in the cycle the late secretory state of the endometrium, which is characteristic of adequate luteal support, was observed more often with 400 mg pessaries bid (90%) than with vaginal gel (82%) and with lower pessary doses (64-78%). Pharmacokinetic parameters after repeated dosing of vaginal pessaries showed a dose-dependent, but not dose-proportional, increase of plasma progesterone levels. The lowest incidence of bleeding and spotting was reported during treatment with 400 mg pessaries bid. LIMITATIONS REASONS FOR CAUTION:The primary outcome parameter, rate of secretory transformation of the endometrium, is a surrogate for endometrial receptivity and for the actual clinical efficacy. WIDER IMPLICATIONS OF THE FINDINGS:Delivery of progestesterone through 400 mg pessaries bid is an effective alternative method for luteal support in ART. STUDY FUNDING/COMPETING INTEREST(S):The study was funded by Actavis Group PTC ehf., Iceland, part of Teva Pharmaceuticals, and L.D. Collins. I.D. and C.K. are directors of Dinox, a contract research organisation. I.K. is Managing Director of Pharmaplex and M.W. is Managing Director of M.A.R.C.O., service organisations involved in organisation/supervision and evaluation/reporting of clinical trials. All received funding for the conduct of the study from Actavis. S.H. and Th.M. are employees of Actavis. TRIAL REGISTRATION NUMBER:EudraCT number 2012-001726-95.

OBJECTIVE: To determine whether twice daily dosing of progesterone vaginal gel (PVG) is better for luteal phase support (LPS) than once daily dosing.

STUDY DESIGN: Retrospective study including 456 women aged ≤42 years who underwent assisted reproductive technology with long GnRH agonist protocol. Blastocyst transfers and difficult embryo transfers were excluded. LPS was started with 90 mg PVG once daily on the evening of oocyte retrieval and continued until negative pregnancy test or 10th week of pregnancy in both groups. PVG dosage was doubled on the day of embryo transfer in the twice-daily group.

RESULTS: Age, duration of infertility, and number of oocytes collected were similar. Numbers of embryos transferred were 2.9 and 2.8 in the once-daily and twice-daily groups, respectively (p=0.04). Embryo implantation (23.96% vs. 27.95%) and clinical pregnancy (50.9% vs. 56.5%) rates favored twice-daily dosage; however, differences were statistically nonsignificant, and the study had 20% power to demonstrate significance. When our results were pooled with a prior trial comparing once and twice daily dosing, twice daily dosing seemed to significantly increase clinical pregnancy rate (rate ratio: 1.18, 95% CI 1.01-1.38).

CONCLUSION: Trends favoring twice daily dosing are encouraging findings
and require further investigation.