OBJECTIVE: To examine the association between preovulation body mass index and pregnancy outcomes after frozen embryo transfer in patients with polycystic ovary syndrome with insulin resistance.
METHODS: This was a single-center, retrospective cohort study.
METHODS: Women with infertility, diagnosed with polycystic ovary syndrome and insulin resistance, and treated at the Reproductive Medicine Center, Second People\'s Hospital of Nanning, China, between January 2020 and August 2023, were included.
METHODS: Patients were divided into four groups according to their body mass index (BMI): slim (<18.5 kg/m2), normal (18.5≤ BMI <24 kg/m2), overweight (24≤ BMI <28 kg/m2), or obese (≥28 kg/m2).
METHODS: The main pregnancy outcomes included rates of embryo implantation, biochemical pregnancy, clinical pregnancy, and ongoing pregnancy.
RESULTS: In total, 282 eligible patients were included. A linear association was observed between the BMI and clinical pregnancy outcomes of the first frozen embryo transfer (P for nonlinearity>0.05). After accounting for all potential variables, each 1 kg/m2 increase in BMI was linked to a 2% decrease in the embryo implantation rate (P<0.05), 11% decrease in the frequency of biochemical pregnancy (P<0.05), and 9% decrease in the both clinical (P<0.05) and ongoing pregnancy rates.
CONCLUSIONS: In patients with polycystic ovary syndrome and insulin resistance, a higher BMI was associated with lower rates of embryo implantation, biochemical pregnancy, clinical pregnancy, and ongoing pregnancy.

OBJECTIVE: To compare the pregnancy and perinatal outcomes of frozen-thawed embryo transfer (FET) in patients following transcervical resection of adhesions (TCRA) versus patients with normal uterine morphology, and to investigate the factors influencing pregnancy outcomes in patients undergoing FET after TCRA.
METHODS: We retrospectively analyzed FET cycles from September 2014 to September 2023, comparing patients with normal uterine morphology to those with intrauterine adhesions (IUAs) treated with TCRA. Propensity score matching (PSM) adjusted for confounding factors. LASSO regression and multivariate logistic regression identified predictors of outcomes, which were visually represented in nomograms. Model performance was assessed using calibration curves, ROC curves, and DCA, with bootstrap method for internal validation.
RESULTS: Post-PSM analysis showed higher live birth rates in patients with normal uterine morphology after clinical pregnancy (75.1% vs. 61.7%, P < 0.001). No significant differences were noted in clinical pregnancy rates and perinatal outcomes between the groups. Factors influencing clinical pregnancy in FET after TCRA included basal progesterone levels, endometrial thickness, parity, infertility cause, embryo stage at transfer, number and quality of embryos transferred, IUA severity, and TCRA surgical procedures. Body mass index, basal LH levels, and day 14 HCG levels post-embryo transfer were determinants of live birth outcome.
CONCLUSIONS: FET cycles following TCRA showed a lower rate of successful live births, but TCRA did not increase adverse perinatal outcome risks. Our study introduces an innovative predictive model for clinical pregnancy and live birth outcomes in patients undergoing FET following TCRA, addressing a significant void in existing research.

UNASSIGNED: This study aims to explore the relationship between different endometrial preparations and pregnancy outcomes among patients with regular ovulatory cycles in order to find the best endometrial preparation methods in the freeze-thaw embryo transfer (FET) cycle.
UNASSIGNED: This is a retrospective study to investigate FET pregnancy outcomes in women who had a regular menstrual cycle, were younger than 35 years old, and underwent a modified natural cycle (mNC), ovulation induction (OI), or a hormone replacement treatment (HRT) cycle. A total of 1071 frozen cycles were included for analysis.
UNASSIGNED: The implantation rate and live birth rate (LBR) in the OI group show a significant difference when compared to the mNC and HRT groups (P < 0.01). After adjusting for confounding factors, the logistic regression analysis revealed that the number of embryos transferred, the embryo stage, and quality were significantly associated with clinical pregnancy rate and LBR. The LBR was additionally affected by the mode of the endometrial preparation; the OI cycle could increase LBR.
UNASSIGNED: Endometrial preparation methods affect the LBR in women with a regular menstrual cycle. The OI cycle had an advantage in the LBR of FET.

UNASSIGNED: To investigate the effects of combining gonadotropin-releasing hormone agonist (GnRHa) downregulation with hormone replacement therapy (HRT, GnRHa-HRT) on the clinical outcomes of patients undergoing frozen-thawed embryo transfer (FET).
UNASSIGNED: In this retrospective study, we included patients who had FET between January 2018 and December 2022. They were categorized into HRT and GnRHa-HRT groups based on the endometrial preparation protocol. The study compared the clinical outcomes of patients in two groups. Possible factors affecting clinical outcomes were analyzed using univariate analysis. To analyze the impact of two endometrial preparation methods on clinical outcomes, multifactorial logistic regression was performed.
UNASSIGNED: The rates of clinical pregnancy (47.31% vs. 59.60%), embryo implantation (37.58% vs. 49.65%), biochemical pregnancy (52.36% vs. 64.31%), and early abortion (7.07% vs. 10.77%) were statistically different between the two groups (p < 0.05). Analysis using multifactorial logistic regression showed that there was a 1.65-fold increase in clinical pregnancy rates (OR = 1.65, 95% CI: 1.29-2.12, p < 0.001) and a 1.55-fold increase in embryo implantation rates (OR = 1.55, 95% CI: 1.27-1.90, p < 0.001) in the GnRHa-HRT group when compared to the HRT group. For blastocyst transfer, the clinical pregnancy and implantation rates of the GnRHa-HRT group were significantly higher than those of the HRT group (OR = 1.75, 95% CI: 1.30-2.37, p < 0.001; OR = 1.73, 95% CI: 1.35-2.21, p < 0.001).
UNASSIGNED: In FET cycles, leuprorelin (as a GnRHa) downregulation combined with HRT may improve the clinical outcome of patients compared to the HRT cycle, especially for the clinical pregnancy and embryo implantation rates of patients with blastocyst transfer.

OBJECTIVE: To evaluate the optimal endometrial preparation protocol for frozen-thawed embryo transfer (FET) following hysteroscopic polypectomy.
METHODS: This was a retrospective clinical cohort study involving 464 patients who underwent their first FET after polyp resection between January 2021 and July 2023. The cohorts were categorized into three groups: the natural cycle (NC) group (n = 139), the ovarian induction (OI) group (n = 117), and the hormone replacement therapy (HRT) group (n = 208).
RESULTS: In the initial unadjusted analysis, both NC and OI cycles exhibited similar pregnancy rates but were associated with significantly higher implantation rate (56.5%, 57.1% vs 42.0%, P < 0.001), clinical pregnancy rate (73.4%, 74.4% vs 57.2%, P = 0.001), and ongoing pregnancy rate (OPR; 67.6%, 63.2% vs 51.0%, P = 0.005) compared to the HRT group. Additionally, the three groups demonstrated comparable abortion rate (7.8%, 14.9% vs 10.9%, P = 0.299). After adjusting for potential confounders in the multiple logistic regression model, the HRT protocol resulted in a 54% significantly lower OPR compared to the NC protocol (adjusted odds ratio [aOR] = 0.46, 95% confidence interval [CI]: 0.28-0.77; P = 0.003). Meanwhile, the OPR difference between the OI protocol and the NC protocol remained insignificant (OI vs NC: aOR = 0.62, 95% CI: 0.35-1.12; P = 0.112).
CONCLUSIONS: The ovulatory-FET scheme (NC and OI) following hysteroscopic polyp resection displayed promising clinical outcomes compared with HRT-FET scheme. The regimen without exogenous estrogen administration should be prioritized for endometrial preparation protocol after polypectomy.

This study investigates the effect of GnRHa pretreatment on pregnancy outcomes in artificial endometrial preparation for frozen-thawed embryo transfer (AC-FET) cycles. A systematic review of English language studies published before 1 September 2022, was conducted, excluding conference papers and preprints. Forty-one studies involving 43,021 participants were analyzed using meta-analysis, with a sensitivity analysis ensuring result robustness. The study found that GnRHa pretreatment generally improved the clinical pregnancy rate (CPR), implantation rate (IR), and live birth rate (LBR). However, discrepancies existed between randomized controlled trials (RCTs) and observational studies; RCTs showed no significant differences in outcomes for GnRHa-treated cycles. Depot GnRHa protocols outperformed daily regimens in LBR. Extended GnRHa pretreatment (two to five cycles) significantly improved CPR and IR compared to shorter treatment. Women with polycystic ovary syndrome (PCOS) saw substantial benefits from GnRHa pretreatment, including improved CPR and LBR and reduced miscarriage rates. In contrast, no significant benefits were observed in women with regular menstruation. More rigorous research is needed to solidify these findings.

OBJECTIVE: Does severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the frozen-thawed embryo transfer (FET) cycle affect embryo implantation and pregnancy rates?
CONCLUSIONS: There is no evidence that SARS-CoV-2 infection of women during the FET cycle negatively affects embryo implantation and pregnancy rates.
BACKGROUND: Coronavirus disease 2019 (COVID-19), as a multi-systemic disease, poses a threat to reproductive health. However, the effects of SARS-CoV-2 infection on embryo implantation and pregnancy following fertility treatments, particularly FET, remain largely unknown.
METHODS: This retrospective cohort study, included women who underwent FET cycles between 1 November 2022 and 31 December 2022 at an academic fertility centre.
METHODS: Women who tested positive for SARS-CoV-2 during their FET cycles were included in the COVID-19 group, while those who tested negative during the same study period were included in the non-COVID-19 group. The primary outcome was ongoing pregnancy rate. Secondary outcomes included rates of implantation, biochemical pregnancy, clinical pregnancy, early pregnancy loss, and ongoing pregnancy. Multivariate logistic regression models were applied to adjust for potential confounders including age, body mass index, gravidity, vaccination status, and endometrial preparation regimen. Subgroup analyses were conducted by time of infection with respect to transfer (prior to transfer, 1-7 days after transfer, or 8-14 days after transfer) and by level of fever (no fever, fever <39°C, or fever ≥39°C).
RESULTS: A total of 243 and 305 women were included in the COVID-19 and non-COVID-19 group, respectively. The rates of biochemical pregnancy (58.8% vs 62.0%, P = 0.46), clinical pregnancy (53.1% vs 54.4%, P = 0.76), implantation (46.4% vs 46.2%, P = 0.95), early pregnancy loss (24.5% vs 26.5%, P = 0.68), and ongoing pregnancy (44.4% vs 45.6%, P = 0.79) were all comparable between groups with or without infection. Results of logistic regression models, both before and after adjustment, revealed no associations between SARS-CoV-2 infection and rates of biochemical pregnancy, clinical pregnancy, early pregnancy loss, or ongoing pregnancy. Moreover, neither the time of infection with respect to transfer (prior to transfer, 1-7 days after transfer, or 8-14 days after transfer) nor the level of fever (no fever, fever <39°C, or fever ≥39°C) was found to be related to pregnancy rates.
CONCLUSIONS: The retrospective nature of the study is subject to possible selection bias. Additionally, although the sample size was relatively large for the COVID-19 group, the sample sizes for certain subgroups were relatively small and lacked adequate power, so these results should be interpreted with caution.
CONCLUSIONS: The study findings suggest that SARS-CoV-2 infection during the FET cycle in females does not affect embryo implantation and pregnancy rates including biochemical pregnancy, clinical pregnancy, early pregnancy loss, and ongoing pregnancy, indicating that cycle cancellation due to SARS-CoV-2 infection may not be necessary. Further studies are warranted to verify these findings.
BACKGROUND: This study was supported by the National Key Research and Development Program of China (2023YFC2705500, 2019YFA0802604), National Natural Science Foundation of China (82130046, 82101747), Shanghai leading talent program, Innovative research team of high-level local universities in Shanghai (SHSMU-ZLCX20210201, SHSMU-ZLCX20210200, SSMU-ZLCX20180401), Shanghai Jiao Tong University School of Medicine Affiliated Renji Hospital Clinical Research Innovation Cultivation Fund Program (RJPY-DZX-003), Science and Technology Commission of Shanghai Municipality (23Y11901400), Shanghai Sailing Program (21YF1425000), Shanghai\'s Top Priority Research Center Construction Project (2023ZZ02002), Three-Year Action Plan for Strengthening the Construction of the Public Health System in Shanghai (GWVI-11.1-36), and Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant Support (20161413). The authors have no conflicts of interest to declare.
BACKGROUND: N/A.

OBJECTIVE: 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 achieved after FET in an HRC.
METHODS: We performed a case-control study in two tertiary perinatal centres in Japan. Among 14,028 patients who delivered at ≥24 weeks of gestation or were transferred after delivery to two tertiary perinatal centres between 2010 and 2021, 972 conceived with ART and 13,056 conceived without ART. PAS was diagnosed on the basis of the FIGO classification for the clinical diagnosis of PAS or retained products of conception after delivery at ≥24 weeks of gestation. We excluded women with fresh embryo transfer, FET with a spontaneous ovulatory cycle, a donor oocyte cycle, and missing details of the ART treatment. Finally, 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 caesarean 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 ≥2 previous uterine surgeries (adjusted odds ratio, 3.57; 95 % confidence interval, 1.60-7.97) and the stage of embryo transfer (blastocysts: adjusted odds ratio, 2.89; 95 % confidence interval, 1.15-7.26). In patients with <2 previous uterine surgeries, PAS was associated with an endometrial thickness of <7.0 mm (adjusted odds ratio, 5.18; 95 % confidence interval, 1.10-24.44).
CONCLUSIONS: Multiple uterine surgeries and the transfer of blastocysts are risk factors for PAS in pregnancies conceived after FET in an HRC. In women with <2 previous uterine surgeries, a thin endometrium before FET is also a risk factor for PAS in these pregnancies.

OBJECTIVE: To investigate whether immediate frozen-thawed embryo transfer (FET) in the next month following coronavirus disease 2019 (COVID-19) recovery affects ongoing pregnancy outcome.
METHODS: This was a retrospective cohort study carried out at a university-affiliated reproductive medicine center. The study group (post-COVID-19 group) comprised women who were affected by COVID-19 in December 2022 and immediately underwent FET in January 2023 after recovery, with transferred embryos not exposed to the infection. The control group comprised women treated during the pre-COVID-19 period (January 2019). Multivariable logistic regression analysis and a propensity score matching (PSM) approach were used to control potential confounders and selection bias.
RESULTS: A total of 200 women were included in the post-COVID-19 group and 641 women were enrolled in the control group. The rate of ongoing pregnancy was comparable between the study cohorts in both the unadjusted and confounder-adjusted logistic regression models. Other reproductive outcomes, including the odds of a positive pregnancy test, implantation, clinical pregnancy and early pregnancy loss, were similar between the comparison groups. PSM models further confirmed the lack of significant differences in pregnancy outcome between the post-COVID-19 group and the control group.
CONCLUSIONS: Among patients affected by COVID-19 for whom the transferred embryos were generated prior to infection, an immediate FET cycle in the next month after recovery does not seem to compromise ongoing pregnancy outcome. Thus, women who have frozen embryos from preinfection cycles should be counseled and encouraged to undergo FET as soon as possible after COVID-19 recovery. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

OBJECTIVE: To compare the hypertensive disorders of pregnancy (HDP) risk between vaginal and intramuscular (IM) progesterone in programmed frozen-thawed embryo transfer (FET) cycles.
METHODS: This was a retrospective cohort study at a tertiary hospital, and only women who achieved ongoing pregnancy after programmed FET between January 2018 and June 2022 were included. Women with chronic hypertension before pregnancy or with history of gestational hypertension or pre-eclampsia in previous pregnancies were excluded. All women were divided into IM progesterone or vaginal progesterone groups according to the route of progesterone supplementation. Follow-up information on obstetric complications and neonatal outcomes were obtained by telephonic interviews. The primary outcome was HDP. Association between routes of progesterone supplementation and HDP was assessed by subgroup analysis and multivariable logistic regression.
RESULTS: A total of 5891 programmed FET cycles (3196 IM progesterone cycles and 2695 vaginal progesterone cycles) were included in the analysis. The prevalence of HDP in the IM progesterone group was significantly lower than that of the vaginal progesterone group (6.54% vs 9.17%, P < 0.001). Therein, the prevalence of gestational hypertension (3.57% vs 4.94%, P = 0.009) and pre-eclampsia (2.97% vs 4.23%, P = 0.009) in the IM progesterone group were all significantly lower as compared to the vaginal progesterone group. According to subgroup analysis, IM progesterone was associated with lower HDP risk in all subgroups. The logistic regression analysis showed that the IM progesterone cycles were associated with lower risk of HDP compared to vaginal progesterone cycles (adjusted odds ratio 0.66, 95% CI: 0.54-0.80, P < 0.001).
CONCLUSIONS: Among women undergoing programmed FET cycles, progesterone supplementation with IM progesterone was associated with reduced HDP risk compared to vaginal progesterone.