Hormone Replacement Cycle Research Articles

The PPOS protocol mitigates the detrimental effects of high BMI on embryo and clinical pregnancy outcomes

BackgroundThe impact of high body mass index (BMI) on embryo and pregnancy outcomes in women using the PPOS (progestin-primed ovarian stimulation) protocol during their first frozen embryo transfer (FET) cycles is not clear. This study is to investigate the impact of BMI on oocyte, embryo, and pregnancy outcomes in patients who underwent the PPOS protocol.MethodsThis retrospective study included the first FET cycle of 22,392 patients following the PPOS protocol. The impact of BMI on oocyte and pregnancy outcomes was assessed across different BMI groups, using direct acyclic graph to determine covariates, followed by the application of multiple linear and logistic regressions to further validate this influence.ResultsThe high BMI groups exhibited a higher number of oocytes; however, no significant differences were observed in good-quality embryos, clinical pregnancy rate, and implantation rate. Nevertheless, the high BMI groups demonstrated a significantly elevated miscarriage rate (9.9% vs. 12.2% vs. 15.7% vs. 18.3%, P < 0.001), particularly in late miscarriages, resulting in lower live birth rates (LBR, 41.1% vs. 40.2% vs. 37.3% vs. 36.2%, P = 0.001). These findings were further confirmed through multiple liner and logistic regression analyses. Additionally, several maternal factors showed significant associations with adjusted odds ratios for early miscarriage. However, women with a BMI ≥ 24 who underwent hormone replacement cycle or hMG late stimulation protocol for endometrial preparation experienced an increased risk of late miscarriage.ConclusionsBy utilizing the PPOS protocol, women with a high BMI exhibit comparable outcomes in terms of embryo and clinical pregnancies. However, an elevated BMI is associated with an increased risk of miscarriage, leading to a lower LBR. Adopting appropriate endometrial preparation protocols such as natural cycles and letrozole stimulation cycles may potentially offer benefits in reducing miscarriages.

Differences in perinatal complications and serum hormone levels due to uterine endometrial preparation methods in frozen-thawed embryo transfer.

In frozen-thawed embryo transfer (FET), differences in endometrial preparation methods affect the incidence of perinatal complications. However, the underlying causes are unclear. We aimed to investigate whether serum E2, P4 levels are associated with perinatal complications. This is a retrospective cohort study, involving 306 successful FET pregnancies from 2017 to 2022. Participants were divided into Natural Cycle (NC) and Hormone Replacement Cycle (HRC) group. We compared serum hormone levels, maternal backgrounds, and perinatal outcomes and complications. Furthermore, within the HRC group, serum hormone levels were compared for perinatal complications previously reported to show differences in incidence rates depending on the method of endometrial preparation. HRC exhibited significantly higher serum E2 levels during the implantation period, but lower P4 levels during ovulation, implantation, and pregnancy test period compared with NC. HRC also had significantly higher rates of postpartum hemorrhage (PPH) and placenta accreta spectrum (PAS). There was no association found between perinatal complications more likely to occur in HRC and serum E2, P4 levels. In HRC, there were more occurrences of PPH and PAS. Although serum E2, P4 levels during FET did not correlate with perinatal complications.

O-031 Tacrolimus treatment significantly improved IVF outcomes with euploid embryo transfer in women with repeated implantation failures (RIF) and elevated T helper (Th)1/Th2 cell ratios

Abstract Study question Dose tacrolimus improve implantation rate for RIF women showing elevated T helper (Th)1/Th2 cell ratios, particularly those undergoing IVF/ET with euploid blastocysts? Summary answer Tacrolimus improved the implantation rate in RIF women with elevated Th1/Th2 cell ratios undergoing IVF/ET using euploid blastocysts. What is known already The peripheral blood Th1 and Th2 cells determine immune inflammatory responses at the maternal-fetal interface. Previously, we reported that about 40% of women with RIF (≥4) had elevated Th1/Th2 cell ratios (≥10.3). The pregnancy rate was significantly improved when they were treated with tacrolimus, an immunosuppressive agent [AJRI 2015]. However, genetic embryonic concerns of RIF could not be ruled out since not all transferred embryos were genetically screened. Recently, we reported an adjusted cut-off value of the Th1/Th2 cell ratios (≥11.8) [AJRI 2021] for women with RIF based on the retrospective analysis. However, the prospective study has not been performed. Study design, size, duration A prospective cohort study was performed, including 569 infertile women with more than 4 times of RIF. The study participants received ET with euploid blastocysts from September 2020 to November 2021. All transferred blastocysts were confirmed as euploid or low-frequency mosaic by preimplantation genetic testing for aneuploidy, and the endometrial preparation for ET was made by using either hormone replacement cycle or natural ovulatory cycle. Participants/materials, setting, methods Before ET, all participants were measured for their peripheral blood Th1/Th2 (CD4+IFN-γ+/ CD4+IL-4+) cell ratios in the secretory phase. Women who had elevated Th1/Th2 cell ratios (≥10.3) received tacrolimus (2-4 mg daily). Tacrolimus was started 2 days before ET, and the hCG and gestational sac (GS) rates were calculated in women with or without tacrolimus. Main results and the role of chance Of 569 participants, 174 (30.6%) women showed elevated Th/Th2 cell ratios (≥10.3), whereas the remaining 395 women served as control (Control group). Among 174 women, 148 women received tacrolimus (Tac group), while 26 did not receive tacrolimus (no-Tac group). The hCG and GS rates of the Tac group were 73.0% and 64.2%, respectively, similar to the no-Tac group (69.2% and 57.7%, respectively, P=NS). Meanwhile the hCG and GS rates of the control group were 70.6% and 60.0%, respectively (P=NS). When the Th1/Th2 cell ratio cut-off value was set to ≥ 11.8, 123 women of the 569 participants (21.6%) had elevated Th1/Th2 cell ratios (≥11.8). Among them, 112 received tacrolimus (Tac2 group), and 11 did not tacrolimus (no-Tac2 group). The remaining 410 women were as a control group (Control2 group). The GS rate of the Tac2 group was 67.0%, which was significantly higher than that of the no-Tac group (36.3%, p &amp;lt; 0.05), while the GS rate of the Control2 group was 60.5% (P=NS, vs Control2 group). Tacrolimus dosing data was as follows; 11.8 or more but less than 15.8 of Th1/Th2 cell ratios were needed for 2 mg of tacrolimus daily, and 15.8 pr more was needed for 3 mg of tacrolimus. Limitations, reasons for caution The study was a controlled trial with a limited number of study population. Additionally, the endometrial changes or peripheral immune responses after tacrolimus were not evaluated thoroughly. Further study is needed for the tacrolimus effect on systematic immune responses and local endometrial immune milieu. Wider implications of the findings Before ET, screening for increased Th1/Th2 ratios (Cut-off value ≥11.8) may significantly improve IVF outcomes by selecting proper candidates for tacrolimus treatment and detecting the proper tacrolimus doses. Notably, a significant proportion of women with RIF have additional implantation failures, even with euploid embryos, when immune-inflammatory conditions were not controlled. Trial registration number not applicable

P-760 The effect of assisted hatching on pregnancy outcomes in 1,833,485 single embryo transfer based on Japan Assisted Reproductive Technology Registry System

Abstract Study question Does assisted hatching (AH) affect pregnancy outcomes especially when it was performed selectively on specified group? Summary answer No clinically significant effect of AH on pregnancy outcomes was demonstrated for the entire single embryo transfer (SET) cycle after adjusting for covariates. What is known already AH is a technique used in assisted reproduction by artificially thinning or making a small hole in the zona pellucida in order to facilitate the hatching process. It is suggested that AH may improve the chance of embryo implantation and success of pregnancy. However, there is insufficient evidence to conclude that AH improves pregnancy outcomes, despite its widespread and longtime use. In 2014, the Practice Committee of ASRM recommended that AH should not be conducted routinely for all patients. On the other hands, it has been suggested that AH could be effective for patients with poor prognosis. Study design, size, duration A retrospective observational study based on the national ART registry maintained by the Japan Society of Obstetrics and Gynecology (JSOG) was performed. The study included 1,833,485 single embryo transfer (SET) for in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) from January 2010 to December 2019. This study was approved by the Registration and Research Subcommittee of the JSOG and Tokyo University Ethics Committee. Participants/materials, setting, methods To determine the effect of AH, the rate of clinical pregnancy and live birth were compared in SET with and without AH as primary outcome measures. In addition, the prevalence of miscarriage, multiple pregnancy, ectopic pregnancy, placental malposition, and placenta accreta were analyzed as secondary outcomes. We performed inverse probability of treatment weighting and outcome regression analyses. Main results and the role of chance Out of 1,833,485 SET cycles, AH was conducted in 983,242 cycles (53.6%). In all SET cycles, clinical pregnancy rate (CRP) and live birth rate (LBR) were 31.0% vs. 26.2%, and 21.6% vs. 18.7% in AH vs. without AH group, respectively. AH was more frequently performed in patients with advanced maternal age, frozen-thawed ET cycles (88% vs. 47%, AH vs. without AH), blastocyst transfer cycles (70% vs. 42%), patients with tubal factor (17% vs 14.3%), and hormonal replacement cycles (66% vs. 43%). After adjusting for these covariates, the propensity-weighted CPR (28.4% vs. 29.1%, AH vs. without AH) and LBR (20.1% vs. 20.6%) were slightly yet significantly lower in AH group. As secondary outcomes, AH may lead to increased risk of multiple pregnancy (0.21% increase), ectopic pregnancy (0.02%), and placenta accreta (0.03%), and 0.24% decreased risk of miscarriage. On the other hands, subgroup analysis suggested that AH could be effective in the following cycles: frozen-thawed cycles with either blast or cleavage with maternal age under 35 years, and fresh blastocyst transfer cycles with maternal age over 40 years. Limitations, reasons for caution The limitation of this study is that the information regarding the history of repeated implantation failure and methods of AH were not included in this registry system. Another limitation is that duplicate data from same patients who underwent multiple embryo transfers exists in this retrospective study for 10 years. Wider implications of the findings Despite of frequent use of AH in Japan, AH in SET cycles for all patients is not recommended because of increased risk of adverse events without improvement of pregnancy outcomes. On the other hands, AH may improve pregnancy outcomes for some groups associated with maternal age and duration of culture. Trial registration number not applicable’

P-588 Serum Luteinizing Hormone levels before progesterone supplementation are significantly associated with live birth rate in single euploid frozen embryo transfers performed in hormonal replacement cycles

Abstract Study question Do luteinizing hormone (LH) levels measured prior to initiating progesterone supplementation influence live birth rate (LBR) in artificial frozen-thawed single euploid blastocyst transfer cycles? Summary answer Serum LH levels, measured prior to progesterone initiation in artificial frozen-thawed single euploid blastocyst transfer cycles, are significantly associated with LBR. What is known already In the absence of a dominant follicle, estrogen supplementation in artificial endometrial preparation for frozen embryo transfer (FRET) can lead to a rise in endogenous LH levels, as observed in a natural cycle. Since the LH rise is a key feature in natural conception and the embryo, the endometrium, and the myometrium display receptors for LH, the rise observed during FRET preparation may have an impact on the clinical outcomes of the treatment. Previous studies found contradictory results hence none of them excluded embryo aneuploidy by implementation of preimplantation genetic testing for aneuploidies and the transfer of euploid embryos. Study design, size, duration Retrospective analysis of 639 frozen-thawed single euploid blastocyst transfer cycles performed in a tertiary referral IVF center from January 2018 to August 2023. Cycles with hormonal pre-treatment or pituitary suppression were excluded. Participants/materials, setting, methods Single euploid FRET cycles were included. Oral estradiol administration commenced on cycle-day 2/3. Estradiol, progesterone, and LH were measured at the start of endometrial preparation and up to 3 days before progesterone initiation, and the slope of LH was calculated. Patients were stratified in groups according to their LH values before progesterone administration, and the impact of LH on LBR and implantation rate was assessed. Logistic regression analysis was performed to adjust for potential confounders. Main results and the role of chance In total 639 cycles were included. Patients’ characteristics (mean+/-SD) were: age 33.2±5.9 years; BMI 27.5±4.9 kg/m2. The median duration of estrogen administration was 15 days (range: 11-27 days). The overall implantation rate and LBR were 65.9% (421/639) and 46.9% (300/639), respectively. Patients were stratified into six groups according to their LH levels prior to progesterone supplementation: &amp;lt;10th percentile (≤6mIU/ml, n = 57), p10th-p25th (&amp;gt;6 to ≤ 8.5mIU/ml, n = 81), p25th-p50th (&amp;gt;8.5 to ≤ 12.4mIU/ml, n = 176), p50th-p75th (&amp;gt;12.4 to ≤ 18.1mIU/ml, n = 180), p75th-p90th (&amp;gt;18.1 to ≤ 25.0mIU/ml, n = 91) and &amp;gt;p90th (&amp;gt;25.0mIU/ml, n = 54). A significant trend for higher LBR with increasing serum LH levels was observed (Cochran-Armitage Test, P = 0.041) but not for implantation rate (P = 0.158). Those with higher basal serum estradiol levels before estrogen supplementation had a steeper LH increase from basal to progesterone-supplementation day (0.40 mIU/mL higher per 10pmol/L increase in basal estradiol, P = 0.027). Regression analysis identified as independent predictors of LBR BMI (OR 0.96, 95%CI: 0.93-0.99) and embryo quality (CC vs. AA p &amp;lt; 0.001, CB vs. AA p = 0.027, BC vs. AA p = 0.013). Patients with steeper LH increases from estrogen to progesterone-supplementation day had higher LBR in both univariable (OR:1.27, 95%CI: 1.00–1.63, P = 0.052) and multivariable analyses (OR:1.26, 95%CI: 0.97–1.64, P = 0.085) but the difference didn’t reach statistical significance. Limitations, reasons for caution The retrospective design of the study is a limitation. Results should be interpreted with caution due to the small number of patients in the lowest and highest LH percentile groups. Wider implications of the findings The results of this study suggest that serum LH levels measured before progesterone supplementation may have an impact on the clinical outcome of artificial frozen-thawed blastocyst transfer cycles. Further studies with a higher sample size are necessary to confirm or refute our findings. Trial registration number not applicable

Assisted reproductive technology and prolonged third stage of labour: a multicentre study in Japan

Research questionWhat are the risk factors for a prolonged third stage of labour, closely related to postpartum haemorrhage, and what is the effect of assisted reproductive technology (ART) on the third stage of labour? DesignClinical data of women who delivered vaginally at term at 12 primary maternity hospitals in Japan (2010–2018) (n = 25,336) were obtained; 1148 (4.5%) conceived through ART and 2246 (8.9%) through non-ART treatments. The risk of a prolonged third stage of labour (defined as ≥20 min) was evaluated by univariable and multivariable regression analyses. Adjusted odds ratios (aOR) of a prolonged third stage of labour were evaluated, stratified by the type of ART, with natural conception as a reference. ResultsMultivariable analysis showed that pregnancy achieved through ART (aOR 4.38, 95% CI 3.12 to 6.15), history of spontaneous miscarriage (OR 1.40, 95% CI 1.06 to 1.84) and prolonged labour (OR 1.52, 95% CI 1.09 to 2.12) were identified as independent risk factors. Frozen embryo transfer (FET), FET in a hormone replacement cycle (HRC–FET) and blastocyst-stage embryo transfer were significantly associated with a prolonged third stage of labour (aOR 4.07, 95% CI 2.75 to 6.04, aOR 4.11, 95% CI 2.58 to 6.57 and aOR 2.13, 95% CI 1.15 to 3.95, respectively). No significant difference was observed in the duration of third stage of labour between natural conception and non-ART treatment (P = 0.61). ConclusionPregnancy achieved through ART, particularly FET, HRC–FET and blastocyst-stage embryo transfer, was a significant risk factor for a prolonged third stage of labour.

Effect of a novel copper chloride gel on endometrial growth and function in healthy volunteers

Research questionDoes the application of a micro-dose of copper chloride gel increase endometrial production of vascular endothelial growth factor (VEGF) without compromising endometrial function or producing embryo toxicity? DesignAn estimate of optimal dose was made based on cell culture studies. Ten healthy participants received an initial uterine application of placebo gel, followed by copper chloride gel (37.5 μM, 75 μM, or 150 μM dose) in a later hormone replacement cycle. Endometrial biopsies (day 5.5 luteal) and pelvic ultrasound were carried out during each cycle to evaluate endometrial function and growth. Uterine fluid was assessed for residual copper levels on the day of biopsy, and copper chloride gel underwent mouse embryos assay assessment for potential embryo toxicity. ResultsThe copper gel significantly increased endometrial VEGF expression (quantitative polymerase chain reaction), and also increasing endometrial thickness by an average of 2.2 mm compared with matched control cycles. The copper gel did not adversely affect endometrial morphology or maturation (histological dating and molecular receptivity testing), and mouse embryos assay studies showed no evidence of embryo toxicity. Furthermore, uterine cavity flush samples mostly lacked copper, with only negligible amounts present in one sample. ConclusionApplying copper chloride gel to the uterine cavity upregulated endometrial VEGF and significantly increased endometrial thickness and volume. No adverse effects on the endometrium or embryos were observed. Copper chloride gels show promise for treating suboptimal endometrial thickness if the results of this study are confirmed by larger randomized controlled trials.

Assisted reproductive technology-associated risk factors for placenta accreta spectrum after vaginal delivery

This study aimed to investigate assisted reproductive technology (ART) factors associated with placenta accreta spectrum (PAS) after vaginal delivery. This was a registry-based retrospective cohort study using the Japanese national ART registry. Cases of live singleton infants born via vaginal delivery after single embryo transfer (ET) between 2007 and 2020 were included (n = 224,043). PAS was diagnosed in 1412 cases (0.63% of deliveries), including 1360 cases (96.3%) derived from frozen-thawed ET cycles and 52 (3.7%) following fresh ET. Among fresh ET cycles, assisted hatching (AH) (adjusted odds ratio [aOR], 2.5; 95% confidence interval [CI] 1.4–4.7) and blastocyst embryo transfer (aOR, 2.2; 95% CI 1.3–3.9) were associated with a significantly increased risk of PAS. For frozen-thawed ET cycles, hormone replacement cycles (HRCs) constituted the greatest risk factor (aOR, 11.4; 95% CI 8.7–15.0), with PAS occurring in 1.4% of all vaginal deliveries following HRC (1258/91,418 deliveries) compared with only 0.11% following natural cycles (55/47,936). AH was also associated with a significantly increased risk of PAS in frozen-thawed cycles (aOR, 1.2; 95% CI 1.02–1.3). Our findings indicate the need for additional care in the management of patients undergoing vaginal delivery following ART with HRC and AH.

Predicting risk of endometrial failure: a biomarker signature that identifies a novel disruption independent of endometrial timing in patients undergoing hormonal replacement cycles

To propose a new gene expression signature that identifies endometrial disruptions independent of endometrial luteal phase timing and predicts if patients are at risk of endometrial failure. Multicentric, prospective study. Reproductive medicine research department in a public hospital affiliated with private fertility clinics and a reproductive genetics laboratory. Caucasian women (n = 281; 39.4 ± 4.8 years old with a body mass index of 22.9 ± 3.5 kg/m2) undergoing hormone replacement therapy between July 2018 and July 2021. Endometrial samples from 217 patients met RNA quality criteria for signature discovery and analysis. Endometrial biopsies collected in the mid-secretory phase. Endometrial luteal phase timing-corrected expression of 404 genes and reproductive outcomes of the first single embryo transfer (SET) after biopsy collection to identify prognostic biomarkers of endometrial failure. Removal of endometrial timing variation from gene expression data allowed patients to be stratified into poor (n = 137) or good (n = 49) endometrial prognosis groups on the basis of their clinical and transcriptomic profiles. Significant differences were found between endometrial prognosis groups in terms of reproductive rates: pregnancy (44.6% vs. 79.6%), live birth (25.6% vs. 77.6%), clinical miscarriage (22.2% vs. 2.6%), and biochemical miscarriage (20.4% vs. 0%). The relative risk of endometrial failure for patients predicted as a poor endometrial prognosis was 3.3 times higher than those with a good prognosis. The differences in gene expression between both profiles were proposed as a biomarker, coined the endometrial failure risk (EFR) signature. Poor prognosis profiles were characterized by 59 upregulated and 63 downregulated genes mainly involved in regulation (17.0%), metabolism (8.4%), immune response, and inflammation (7.8%). This EFR signature had a median accuracy of 0.92 (min = 0.88, max = 0.94), median sensitivity of 0.96 (min = 0.91, max = 0.98), and median specificity of 0.84 (min = 0.77, max = 0.88), positioning itself as a promising biomarker for endometrial evaluation. The EFR signature revealed a novel endometrial disruption, independent of endometrial luteal phase timing, present in 73.7% of patients. This EFR signature stratified patients into 2 significantly distinct and clinically relevant prognosis profiles providing opportunities for personalized therapy. Nevertheless, further validations are needed before implementing this gene signature as an artificial intelligence (AI)-based tool to reduce the risk of patients experiencing endometrial failure.

Risk factors for non-previa placenta accreta spectrum in pregnancies conceived through frozen embryo transfer during a hormone replacement cycle in Japan.

Non-previa placenta accreta spectrum (PAS) is associated with assisted reproductive technology (ART), particularly frozen embryo transfer during hormone replacement therapy (HRC-FET). We especially aimed to evaluate the prevalence and risk factors for non-previa PAS in HRC-FET pregnancies. Overall, 279 women who conceived through ART at three ART facilities and delivered at a single center were included in this retrospective study. Data regarding endometrial thickness at embryo transfer, previous histories, and type of embryo transfer-HRC-FET, frozen embryo transfer during a natural ovulatory cycle (NC-FET), and fresh embryo transfer (Fresh-ET)-were collected. Univariable logistic regression analyses were conducted. The prevalence of non-previa PAS was 27/192 (14.1%) in the HRC-FET group and 0 (0.0%) in both the NC-FET and Fresh-ET groups. Significantly high odds ratio [95% confidence interval] of non-previa PAS was associated with a history of artificial abortion (6.45 [1.98-21.02]), endometrial thickness <8.0 mm (6.11 [1.06-35.12]), resolved low-lying placenta (5.73 [2.13-15.41]), multiparity (2.90 [1.26-6.69]), polycystic ovarian syndrome (2.62 [1.02-6.71]), and subchorionic hematoma (2.49 [1.03-6.04]). A history of artificial abortion, endometrial thickness <8.0 mm, and resolved low-lying placenta may help in antenatal detection of a high-risk population of non-previa PAS in HRC-FET pregnancies.

#18 : Risk Factors for Placenta Accreta Spectrum in Pregnancies Conceived after Frozen-Thawed Embryo Transfer in a Hormone Replacement Cycle

Background and Aims: Assisted reproductive technology (ART), especially frozen–thawed embryo transfer (FET) in a hormone replacement cycle (HRC) is a risk factor for placenta accreta spectrum (PAS). This study aimed to clarify the risk factors for PAS related to the maternal background and ART techniques in pregnancies conceived after FET in an HRC. Method: We performed a case–control study in two tertiary perinatal centers in Japan. Among 14,028 patients who delivered at ≥24 weeks of gestation or were transferred after delivery to two tertiary perinatal centers between 2010 and 2021, 972 conceived with ART and 13,056 conceived without ART. PAS was diagnosed in patients 1) with histopathological findings of placenta increta/percreta, 2) those requiring manual evacuation of the placenta after delivery, or 3) those with retained placental tissue. Among women who conceived after FET in an HRC, 62 with PAS and 340 without PAS were included in this study. Multivariate logistic regression models were used for case–control comparisons, with adjustment for maternal age at delivery, parity, endometriosis or adenomyosis, the number of previous uterine surgeries of cesarean section, myomectomy, endometrial polypectomy or endometrial curettage, placenta previa, the stage of transferred embryos and endometrial thickness at the initiation of progestin administration. Results: PAS was associated with [Formula: see text]2 previous uterine surgeries (adjusted odds ratio [OR], 3.57; 95% confidence interval [CI], 1.60–7.97) and the number of blastocysts transferred (adjusted OR, 2.89; 95% CI, 1.15–7.26). In patients with &lt;2 previous uterine surgeries, PAS was associated with an endometrial thickness of &lt;7.0 mm (adjusted OR, 5.18; 95% CI, 1.10–24.44). Conclusion: A history of multiple previous uterine surgeries, the number of blastocysts transferred and a thin endometrium before ET are risk factors for PAS in pregnancies conceived after FET in an HRC.

Assisted reproductive technology-associated risk factors for retained products of conception

ObjectiveTo evaluate assisted reproductive technology-associated risk factors for retained products of conception among live births. DesignRegistry-based retrospective cohort study. SettingNot applicable. Patient(s)Cycle-specific data for a total of 369,608 singleton live births following fresh and frozen–thawed embryo transfers between 2007 and 2017 were obtained from the Japanese assisted reproductive technology registry. Intervention(s)None Main outcome measure(s)Retained products of conception after delivery. Odds ratios and 95% confidence intervals for risk factors associated with retained products of conception during fresh and frozen cycles. Result(s)In total, 132 deliveries (0.04% of eligible assisted reproductive technology registry deliveries) had retained products of conception; 122 (92.4%) of these deliveries occurred after frozen–thawed embryo transfer cycles. Cases with retained products of conception were significantly more likely to have undergone vaginal delivery than cases without retained products of conception (78.0% vs. 61.1%, p < 0.001); they were also more likely to have been complicated with placenta accreta spectrum (24.2% vs. 0.45%, p < 0.001). Among patients undergoing frozen–thawed embryo transfers, factors associated with significantly increased risk of retained products of conception were embryo stage at transfer, use of hormone replacement cycles, and assisted hatching. Use of hormone replacement cycles represented the largest risk factor (adjusted odds ratio, 4.9; 95% confidence interval, 2.0 to 12.4), such that retained products of conception occurred in 0.05% of deliveries following hormone replacement cycles (51 of 97,958 deliveries) but only 0.01% of deliveries following natural cycles (5 of 47,079 deliveries). Subgroup analysis showed that hormone replacement cycles and assisted hatching remained significant risk factors for retained products of conception in cases without polycystic ovary syndrome/anovulation and cases with vaginal delivery, but not cases with cesarean section. Among fresh embryo transfers, an increased number of retrieved oocytes was the only significant risk factor for retained products of conception. Conclusion(s)Our analyses demonstrated that the majority of cases involving retained products of conception were derived from frozen–thawed embryo transfers and identified the use of hormone replacement cycles as the largest risk factor for retained products of conception within this group.

Sex-specific differences in head circumference of term singletons after assisted reproductive technology: a multicentre study in Japan

Research questionDoes fertility treatment, specifically assisted reproductive technology (ART), affect head circumference in term singletons? DesignA total of 32,651 women who delivered at term at 12 maternity hospitals in Japan between 2010 and 2018 were included in the analysis; of these, 1941 (5.9%) and 2984 (9.1%) women conceived through ART and non-ART fertility treatments (timed intercourse, ovulation induction or artificial insemination), respectively. The study evaluated the adjusted odds ratios of head circumference ≥90th percentile stratified by infant sex and type of ART procedure after adjusting for covariates, with natural conception as the reference group. ResultsART significantly increased the risk of head circumference ≥90th percentile (adjusted odds ratio 1.56 [95% confidence interval 1.25–1.96]), whereas non-ART fertility treatment did not increase the risk (1.14 [0.92–1.42]). This increased risk of head circumference ≥90th percentile was observed exclusively in male neonates (1.73 [1.33–2.26]) and not in female neonates (1.18 [0.76–1.85]) in the ART group. Frozen embryo transfer (FET), FET in a hormone replacement cycle (HRC-FET) and blastocyst-stage embryo transfer were significantly associated with head circumference ≥90th percentile (1.60 [1.26–2.02], 1.70 [1.30–2.22] and 1.72 [1.33–2.24], respectively). ConclusionsThe use of ART, particularly FET, HRC-FET or blastocyst-stage embryo transfer, was linked with a heightened risk of head circumference ≥90th percentile compared with non-ART fertility treatment or natural conception. The increased risk was observed only in male neonates.

The cervical transcriptome changes during the menstrual cycle but does not predict the window of implantation.

The expression of genes in female reproductive organs is influenced by the cyclic changes in hormone levels during the menstrual cycle. While the molecular changes in the endometrium that facilitate embryo implantation have been extensively studied, there is limited knowledge about the impact of the menstrual cycle on cervical cells. Cervical cells can be easily and routinely collected using a cytobrush during gynecological examination, offering a standardized approach for diagnostic testing. In this study we investigated how the transcriptome of cervical cells changes during the menstrual cycle and assessed the utility of these cells to determine endometrial receptivity. Endocervical cells were collected with cytobrushes from 16 healthy women at different menstrual cycle phases in natural cycles and from four women undergoing hormonal replacement cycles. RNA sequencing was applied to gain insight into the transcriptome of cervical cells. Transcriptome analysis identified four differentially expressed genes (DEGs) between early- and mid-secretory samples, suggesting that the transcriptome of cervical cells does not change significantly during the opening of the implantation window. The most differences appeared during the transition to the late secretory phase (2136 DEGs) before the onset of menstruation. Cervical cells collected during hormonal replacement cycles showed 1899 DEGs enriched in immune system processes. The results of our study suggested that cervical cells undergo moderate transcriptomic changes throughout the menstrual cycle; however, these changes do not reflect the gene expression pattern of endometrial tissue and offer little or no potential for endometrial receptivity diagnostics.

P-781 Assisted reproductive technology-associated risk factors for retained placenta

Abstract Study question What are the assisted reproductive technology-associated risk factors for retained products of conception (RPOC) following delivery? Summary answer Frozen embryo transfer (FET) with hormone replacement cycles (HRC) constitutes the largest risk factor for RPOC. What is known already RPOC is a key cause of secondary postpartum hemorrhage. Previous studies have shown that the use of ART increases the risk of RPOC and subsequent transfusion following delivery. However, the relationships between specific ART-treatment factors and the risk of RPOC have not been elucidated. Study design, size, duration We performed a registry-based retrospective cohort study using the Japanese national ART registry, in which all the ART cycles performed in Japan are recorded including the perinatal outcomes. Participants/materials, setting, methods Singleton live births between 2007 and 2017 were studied (n = 306,411). Odds ratios (ORs) and 95% confidence intervals (CIs) for the potential risk factors for RPOC associated with fresh and frozen cycles were obtained from multiple logistic regression analysis, incorporating adjustment for maternal age, infertility, and calendar year. Because information regarding assisted hatching (AH) and HRC for endometrial preparation only became available in 2012, these factors were analysed using the data collected between 2012 and 2017. Main results and the role of chance RPOC was diagnosed for 132 deliveries (0.04%), of which 122 (92.4%) followed FET cycles and only 10 (0.01%) followed fresh embryo transfer (ET). No significant risk factors for RPOC were identified using the fresh ET data. For FET cycles, the use of HRC as an endometrial preparation method represented the largest risk factor (adjusted OR, 4.9; 95% CI, 2.0 to 12.3), with RPOC occurring in 0.05% of deliveries following HRC (51/97, 958 deliveries) but in only 0.01% following natural cycles (5/47, 79 deliveries). AH was also associated with a significantly higher risk of RPOC (adjusted OR, 1.9; 95% CI, 1.2 to 3.1), although the risk was lower than that associated with HRC). Subgroup analysis showed that these significant associations of HRC and AH with RPOC were present for transvaginal deliveries, but not deliveries by caesarean section. Limitations, reasons for caution The registry lacks important information regarding risk factors for RPOC, such as parity, body mass index, and history of previous uterine surgery. Furthermore, the lower prevalence of RPOC in the present study (0.04%) than in other studies (approximately 1%) suggests the possibility of non-differential misclassification for the outcomes of RPOC. Wider implications of the findings Although the possibility of residual confounding factors remains, the present findings suggest that additional care should be taken in the management of patients undergoing vaginal deliveries following FET who have HRC or AH. Trial registration number Not applicable

P-630 Comparison of follitropin delta versus follitropin alfa in progestin-primed ovarian stimulation in IVF

Abstract Study question Is there a difference in a clinical outcome between using follitropin delta and follitropin alfa undergoing a progestin primed ovarian stimulation (PPOS) protocol? Summary answer There was no difference between follitropin delta and follitropin alfa in terms of pregnancy rates. What is known already Follitropin delta (REKOVELLE, Ferring Pharmaceuticals, Switzerland) is the first recombinant human follicle-stimulating hormone (FSH) using the algorithm-based individualized dosing regimen while reducing the risk of ovarian hyperstimulation syndrome (OHSS) as compared with conventional dosing strategies. The efficacy and safety of follitropin delta has been demonstrated in randomized controlled trials (RCTs). Study design, size, duration We performed a retrospective analysis of 645 patients who underwent ovarian stimulation by a PPOS protocol using follitropin delta or follitropin alfa between April 2022 and August 2022. (325 patients using follitropin delta and 320 patients using follitropin alfa, respectively.) Participants/materials, setting, methods 325 cycles of women who used follitropin delta were compared to 320 cycles of women who used follitropin alfa. The following outcomes were analysed; fertilized rate, 2 pronuclear embryo rate, good quality embryo rate, blastocyst rate, good quality blastocyst rate. A total of 499 women who underwent embryo transfer in cryo cycles using natural cycle or hormone replacement cycle were analysed about biochemical pregnancy rate, clinical pregnancy rate. Main results and the role of chance Baseline demographics for 325 women in follitropin delta group and 320 women in follitropin alfa were: age, 35.1±4.3 years and 35.2±4.3 years; number of previous IVF cycles, 1.6±1.6 and 1.7±1.7, respectively. The laboratory data were: fertilization rate, 81.4% and 80.1%, 2 pronuclear embryo rate, 73.9% and 71.5%, good quality cleavage stage embryo rate, 59.4% and 55.9%, blastocyst rate, 58.9% and 55.7%, good quality blastocyst rate, 41.3% and 38.7%, respectively. Only good quality cleavage stage embryo rate and good quality blastocyst rate were significantly higher (P &amp;lt; 0.05) in follitropin delta group. A vitrified-warmed embryo transfer was performed for 257/325 women (79.1%) and 242/320 women (75.6%) and subsequent positive β-human chorionic gonadotropin (βhCG) reported for 218/621 cycles (35.1%) and 194/570 cycles (34.0%), respectively. Ongoing pregnancy rate after embryo transfer were 19.2% (n = 119) and 19.6% (n = 112) and cumulative ongoing pregnancy rate were both 46.3%. Mild OHSS was reported for 131 women (40.3%) and 170 women (53.1%), respectively (P = 0.07). Limitations, reasons for caution This is a non-controlled, retrospective study. Wider implications of the findings The present study shows that in addition to reducing the OHSS risk, follitropin delta in its individualised fixed-dose regimen has the potential to improve the quality of embryos although there was no significant difference in clinical outcomes. Trial registration number not applicable

P-483 Application of RNA-sequencing based predictive model for endometrial WOI in patients with recurrent implantation failure: a prospective cohort study

Abstract Study question Is intrauterine pregnancy rate following a FET timed by the rsERT with hour precision higher than the conventional FET among patients with recurrent implantation failure? Summary answer Personalized embryo transfer (pET) guided by this newly optimized rsERT significantly improved pregnancy outcomes of patients with recurrent implantation failure (RIF). What is known already Asynchrony between blastocyst and endometrium is responsible for implantation failures. Hence, accurate prediction for endometrial window of implantation (WOI) would maximize the effectiveness of assisted reproductive technology (ART). Previously, we have established a predictive model for endometrial WOI (rsERT) by three-time points sampling from the same patient at 48-hour intervals during one menstrual cycle. To avoid multiple sampling and build a more efficient WOI prediction tool, estimation method with hour precision by single time point sampling is urgently needed. Study design, size, duration This was a two-phase strategy involving model optimization and benefit evaluation with a prospective controlled trial. The study was performed in a tertiary hospital setting between September 2018 and December 2021. In the first phase (September 2018-June 2020), 91 participants were recruited to optimize the rsERT. In the second phase (June 2020-December 2021), 176 patients with RIF were enrolled to valida the clinical efficacy of this newly optimized rsERT. Participants/materials, setting, methods First phase: endometrium samples were obtained from sampling on LH + 5, +7, +9 or P + 3, +5, +7 respectively. Samples were predicted by the rsERT. Only those in agreement with theoretical WOI timing and from whom successfully obtained intrauterine clinical pregnancy after subsequent FET were eligible. Second phase: 88 patients in the experimental group underwent pET timed by rsERT after sampling at LH + 7 or P + 5. 88 patients in the control group performed standard embryo transfer without sampling. Main results and the role of chance This newly optimized predictive model could provide hour-based results of endometrial WOI and have an average accuracy of 94.51% by using 10-fold cross validation. In the second phase, a total of 88 NGS were constructed for RNA-sequencing by using endometrial biopsy samples from RIF patients in the experimental group (n = 88). The results indicated WOI displacement in 40 of 88 (45.45%). Among them, advanced WOI occurred in two patients (2/40, 5.00%), and delayed WOI occurred in 38 patients (38/40, 95.00%). The baseline clinical parameters, including age, BMI, infertility duration, types of infertility, number of previous failed cycles, main aetiology of infertility, the prevalence of pre-implantation genetic screening/diagnosis (PGS/PGD), endometrial thickness, endometrial types, the percentage of transferred blastocysts, good-quality embryo transferred rate and number of transferred embryos were all comparable between the two groups (P &amp;gt; 0.05). The intrauterine pregnancy rate (IPR) and implantation rate (IR) of the experimental group were significantly improved compared to those of the control group (for IPR: 61.36% vs. 31.82%, RR 3.630, 95%CI 1.958-6.732, P = 0.000; for IR: 42.86% vs. 24.66%, RR 2.292, 95%CI 1.392-3.772, P = 0.001). Moreover, in the experimental group, pregnancy outcomes did not exhibit remarkable differences between the natural cycle and hormone replacement (HRT) cycle. Limitations, reasons for caution Caution is warranted due to the non-randomized design and limited sample size of the study. Besides, embryonic factors should be taken into consideration as well. Hence, a multi-center randomized controlled trial of rsERT combined with PGT is needed to further validate its clinical efficacy. Wider implications of the findings These data add a new alternative of predictive model for endometrial WOI among Chinese women. Trial registration number the National Key Research and Development Program of China

Hyaluronan-enriched transfer medium (HETM) can improve the implantation rate in morphologically poor euploid blastocyst transfer

PurposeHyaluronan-enriched transfer medium (HETM) could improve the clinical pregnancy rate (CPR) for patients with repeated implantation failures (RIF). In contrast, there have been seldom reports addressing the potentially beneficial effects of HETM for morphologically poor blastocysts (MPBLs). Our study aimed to evaluate whether the use of HETM would improve the CPR for the patients who were transferred with euploid MPBLs.MethodsPatients who underwent single euploid blastocyst transfer between July 2020 and June 2022 were enrolled. We included only those blastocysts confirmed as euploid by PGT-A, and those blastocysts were transferred after thawing. The natural ovulatory cycle or hormone replacement cycle (HRC) protocol were used for endometrial preparation for frozen embryo transfer (FET). A total of 1,168 FET cycles were performed in the study period, including 954 cycles of morphologically good blastocysts (≥ 4BB in Gardner’s classification), and 85 cycles of MPBLs, of which 47 were transferred using HETM in FET (the HETM group), and the remaining 38 were transferred with the medium without hyaluronan (the control group). We compared the CPR between these two groups.ResultsThe characteristics of patients were similar between the HETM and control groups. The CPR in the HETM group was significantly higher than the control group (47.4% and 21.5%, respectively, p = 0.019). The multiple logistic regression analysis found that the use of HETM was a predictive factor of positive pregnancy outcomes (OR = 5.08, 95% CI = 1.62–16.0, p = 0.019).ConclusionOur data suggests that HETM used in the euploid blastocyst transfer can improve the clinical pregnancy rates of morphologically poor blastocysts.

Efficacy of Hyaluronan-Enriched Transfer Medium for Low-Grade Frozen Embryo Transfer.

This study aimed to retrospectively evaluate the efficacy of a hyaluronan-enriched transfer medium (HETM) for transfer failures and transfer of frozen embryos that have been graded as C at the time of transfer according to the Gardner classification of trophectoderm (TE). This study included 365 cycles of unsuccessful frozen-thawed embryo transfers in hormone replacement cycles graded C according to the Gardner classification of TE at the time of transfer. Clinical pregnancy rates were compared using the χ2 test, with the patients divided into two groups: one whose transfers did include HETM (HETM group) and one whose transfers did not include HETM (control group). As a subgroup analysis, patients with a TE grade of C at the time of transplantation were divided into two groups: those aged 39 years or younger and those aged 40 years or older at the time of transplantation. The clinical pregnancy rates of the groups with and without HETM were then compared. No difference in the clinical pregnancy rates between the HETM and control groups was observed. Hyaluronic acid is believed to favor implantation by promoting adhesion between the embryo and the endometrium, and there are reports of improved implantation and pregnancy rates as a result of HETM. However, the present results suggest limited effectiveness for HETM. Further case series should be conducted, and the suitability of its use as a treatment should be investigated.

Evaluation of Early Frozen Blastocyst Transfer in A True Natural Cycle Protocol in Comparison to A Hormone Replacement Protocol: A Single-Center Cohort Study.

Timing of frozen embryo transfer (FET) within a purported window of implantation is of increasing interest, and there is a paucity of evidence surrounding the transfer of frozen embryos early within these frozen embryo transfer protocols. This study aimed to evaluate whether live birth rates were equivalent after FET of blastocysts 4 days after luteinizing hormone (LH) surge in a true natural cycle protocol, compared to a hormone replacement (HR) protocol. Single-centre, retrospective cohort study involving patients undergoing autologous frozen blastocyst transfer from January 1st, 2013, to December 31st, 2016. Cycles were grouped according to their protocol: true natural cycle (hormonal detection of LH surge with FET scheduled four days later) versus HR cycle (luteal phase gonadotropin-releasing hormone agonist suppression, oral or vaginal estradiol and intramuscular progesterone starting five days before FET). A total of 850 cycles were included, 501 true natural cycles and 349 HR cycles. The primary outcome was the live birth rate, secondary outcomes included clinical pregnancy rate and miscarriage. Logbinomial regression models were performed adjusting for a priori selected variables. Adjusted resulted in live birth rates of 38.7 and 40.4%, [adjusted risk ratio (aRR): 0.96, 95% confidence interval (CI): 0.76-1.22, P=0.729] in the natural cycle and HR groups, respectively. The secondary outcome analyses did not demonstrate any statistically significant difference in the rate of positive human chorionic gonadotropin (hCG), clinical intrauterine pregnancy rate, or miscarriage rate. The timing of the FET four days after LH surge in a true natural cycle protocol results in equivalent live birth rates compared to a HR protocol. Results of this study suggest that the window of implantation within the natural cycle may be less finite than currently believed and further prospective studies evaluating the timing of frozen embryo transfer are warranted.