Systematic review update and meta-analysis of randomized and non-randomized controlled trials of ovarian stimulation versus artificial cycle for endometrial preparation prior to frozen embryo transfer in women with polycystic ovary syndrome

Ovulation-induced frozen embryo transfer regimens in women with polycystic ovary syndrome: a systematic review and meta-analysis

PURPOSE

To evaluate whether the type of frozen embryo transfer (FET) regimen - ovulation-induced regimens vs. hormone replacement therapy regimens (HRT) - is associated with live birth rates and the risk of hypertensive diseases of pregnancy (HDP) in women with polycystic ovary syndrome (PCOS).

METHODS

All studies in PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov were searched using a combination of MeSH terms and keywords. Inclusion criteria included studies on women with a diagnosis of PCOS, utilization of FET, and reporting of pregnancy and/or obstetric outcomes. Studies were excluded if they were case series or conference abstracts or used other FET regimens. A random effects meta-analysis was performed. Primary outcomes include relative risk (RR) of live birth and HDP.

RESULTS

Eleven studies were included in the meta-analysis for the final review. Ovulation-induced regimens were associated with a higher live birth rate (8 studies, RR 1.14 [95% CI 1.08, 1.21]) compared to HRT regimens. The risk of HDP (3 studies RR 0.78 [95% CI 0.53, 1.15]) was not significantly different. Ovulation-induced regimens were associated with a lower miscarriage rate (9 studies, RR 0.67 [95% CI 0.59-0.76]). Rates of clinical pregnancy (10 studies, RR 1.05 [95% CI 0.99, 1.11]) and ectopic pregnancy (7 studies, RR 1.40 [95% CI 0.84, 2.33]), were not significantly different.

CONCLUSION

This SR/MA demonstrates that for women with PCOS, ovulation-induced FET regimens are associated with higher rates of live birth and lower rates of miscarriage compared to HRT regimens.

Genetic and Epigenetic Landscape for Drug Development in Polycystic Ovary Syndrome

The treatment of polycystic ovary syndrome (PCOS) faces challenges as all known treatments are merely symptomatic. The US Food and Drug Administration has not approved any drug specifically for treating PCOS. As the significance of genetics and epigenetics rises in drug development, their pivotal insights have greatly enhanced the efficacy and success of drug target discovery and validation, offering promise for guiding the advancement of PCOS treatments. In this context, we outline the genetic and epigenetic advancement in PCOS, which provide novel insights into the pathogenesis of this complex disease. We also delve into the prospective method for harnessing genetic and epigenetic strategies to identify potential drug targets and ensure target safety. Additionally, we shed light on the preliminary evidence and distinctive challenges associated with gene and epigenetic therapies in the context of PCOS.

Letrozole ovulation regimen for frozen-thawed embryo transfer in women with polycystic ovary syndrome: study protocol for a randomized controlled trial

BACKGROUND

Women with polycystic ovary syndrome (PCOS) are usually selected to undergo an ovulation induction regimen or a programmed regimen for endometrial preparation in the frozen-thawed embryo transfer (FET) during their IVF/ICSI treatment. The programmed regimen permits flexible scheduling of embryo transfer but requires long-term usage of exogenous estrogen and higher dosages of luteal support while the letrozole ovulation regimen needs lower dosages of luteal support only. Recently, multiple studies have shown that the letrozole ovulation regimen can improve pregnancy outcomes of FET in women with PCOS compared with the programmed regimen. However, most of these studies are retrospective, and prospective studies are urgently needed the evidence from the perspective study is insufficient.

METHODS/DESIGN

We are undertaking a multicentre, randomized, controlled clinical trial of an endometrial preparation regimen for FET in women with PCOS. The eligible women are randomly assigned to either the letrozole ovulation regimen or the programmed regimen for endometrial preparation. The primary outcome is the clinical pregnancy rate.

DISCUSSION

The results of this study will provide evidence for whether the letrozole ovulation regimen for endometrial preparation could improve pregnancy outcomes in PCOS women undergoing FET.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2200062244. Registered on 31 July 2022.

Ideal frozen embryo transfer regime

PURPOSE OF REVIEW

This review aims to compare evidence on four criteria (embryo implantation, obstetric outcomes, patient convenience, and IVF-unit efficiency) by analyzing published research on different endometrial preparation methods for frozen embryo transfer (FET).

RECENT FINDINGS

While the artificial-FET cycle provides advantages in scheduling and implantation, it falls short in ensuring optimal obstetric outcomes. In contrast, natural-FET ensures embryo implantation conditions if ovulation is correctly identified. Supplementing with exogenous progesterone shields against low corpus luteum progesterone secretion, crucial for positive obstetric outcomes. In mNC-FET, ovulation is hCG-triggered, closely resembling natural cycles and reducing monitoring visits for enhanced patient convenience.Letrozole is a recommended option for anovulatory patients, preserving endometrial thickness. It is cost-effective, less likely to induce multifollicular development than gonadotropins, and better tolerated.In a novel approach, the natural-proliferative-phase-FET initiates progesterone in an unmediated ovulatory cycle at 7 mm endometrial thickness, combining the benefits of a natural proliferative endometrium with the convenience of scheduled artificial cycles.

SUMMARY

The artificial cycle offers scheduling advantages, but may compromise obstetric outcomes. Natural FET relies on accurate ovulation timing for successful implantation. mNC-FET simplifies the process using hCG induction, minimizing clinic visits for improved convenience. Letrozole is highlighted as a cost-effective and well tolerated option in anovulatory patients. A recent innovative approach combines elements of natural and artificial cycles, showing promise for FET procedures.

Is large for gestational age in singletons born after frozen embryo transfer associated with freezing technique or endometrial preparation protocol? A longitudinal national French study

STUDY QUESTION

Is large for gestational age (LGA) observed in babies born after frozen embryo transfer (FET) associated with either the freezing technique or the endometrial preparation protocol?

SUMMARY ANSWER

Artificial cycles are associated with a higher risk of LGA, with no difference in rate between the two freezing techniques (vitrification versus slow freezing) or embryo stage (cleaved embryo versus blastocyst).

WHAT IS KNOWN ALREADY

Several studies have compared neonatal outcomes after fresh embryo transfer (ET) and FET and shown that FET is associated with improved neonatal outcomes, including reduced risks of preterm birth, low birthweight, and small for gestational age (SGA), when compared with fresh ET. However, these studies also revealed an increased risk of LGA after FET. The underlying pathophysiology of this increased risk remains unclear; parental infertility, laboratory procedures (including embryo culture conditions and freezing-thawing processes), and endometrial preparation treatments might be involved.

STUDY DESIGN, SIZE, DURATION

A multicentre epidemiological data study was performed through a retrospective analysis of the standardized individual clinical records of the French national register of IVF from 2014 to 2018, including single deliveries resulting from fresh ET or FET that were prospectively collected in fertility centres. Complementary data were collected from the participating fertility centres and included the vitrification media and devices, and the endometrial preparation protocols.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data were collected from 35 French ART centres, leading to the inclusion of a total of 72 789 fresh ET, 10 602 slow-freezing FET, and 39 062 vitrification FET. Main clinical outcomes were presented according to origin of the transferred embryos (fresh, slow frozen, or vitrified embryos) and endometrial preparations for FET (ovulatory or artificial cycles), comparing five different groups (fresh, slow freezing-ovulatory cycle, slow freezing-artificial cycle, vitrification-ovulatory cycle, and vitrification-artificial cycle). Foetal growth disorders were defined in live-born singletons according to gestational age and sex-specific weight percentile distribution: SGA and LGA if <10th and ≥90th percentiles, respectively. Analyses were performed using linear mixed models with the ART centres as random effect.

MAIN RESULTS AND THE ROLE OF CHANCE

Transfers led to, respectively, 19 006, 1798, and 9195 deliveries corresponding to delivery rates per transfer of 26.1%, 17.0%, and 23.5% after fresh ET, slow-freezing FET, and vitrification FET, respectively. FET cycles were performed in either ovulatory cycles (n = 21 704) or artificial cycles (n = 34 237), leading to 5910 and 10 322 pregnancies, respectively, and corresponding to pregnancy rates per transfer of 31.6% and 33.3%. A significantly higher rate of spontaneous miscarriage was observed in artificial cycles when compared with ovulatory cycles (33.3% versus 21.4%, P < 0.001, in slow freezing groups and 31.6% versus 21.8%, P < 0.001 in vitrification groups). Consequently, a lower delivery rate per transfer was observed in artificial cycles compared with ovulatory cycles both in slow freezing and vitrification groups (15.5% versus 18.9%, P < 0.001 and 22.8% versus 24.9%, P < 0.001, respectively). Among a total of 26 585 live-born singletons, 16 413 babies were born from fresh ET, 1644 from slow-freezing FET, and 8528 from vitrification FET. Birthweight was significantly higher in the FET groups than in the fresh ET group, with no difference between the two freezing techniques. Likewise, LGA rates were higher and SGA rates were lower in the FET groups compared with the fresh ET group whatever the method used for embryo freezing. In a multivariable analysis, the risk of LGA following FET was significantly increased in artificial compared with ovulatory cycles. In contrast, the risk of LGA was not associated with either the freezing procedure (vitrification versus slow freezing) or the embryo stage (cleaved embryo versus blastocyst) at freezing. Regarding the vitrification method, the risk of LGA was not associated with either the vitrification medium used or the embryo stage.

LIMITATIONS, REASONS FOR CAUTION

No data were available on maternal context, such as parity, BMI, infertility cause, or maternal comorbidities, in the French national database. In particular, we cannot exclude that the increased risk of LGA observed following FET with artificial cycles may, at least partially, be associated with a confounding effect of some maternal factors. No information about embryo culture and incubation conditions was available. Most of the vitrification techniques were performed using the same device and with two main vitrification media, limiting the validity of a comparison of risk for LGA according to the device or vitrification media used.

WIDER IMPLICATIONS OF THE FINDINGS

Our results seem reassuring, since no potential foetal growth disorders following embryo vitrification in comparison with slow freezing were observed. Even if other factors are involved, the endometrial preparation treatment seems to have the greatest impact on LGA risk following FET. FET during ovulatory cycles could minimize the risk for foetal growth disorders.

STUDY FUNDING/COMPETING INTEREST(S)

This work has received funding from the French Biomedicine Agency (Grant number: 19AMP002). None of the authors has any conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Women's experience of polycystic ovary syndrome management: A systematic review and meta-synthesis

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common chronic condition in women of child-bearing age. There is currently no effective treatment, so early and long-term management is essential. However, there are many problems in the practice of disease management in women with PCOS that make it difficult to achieve good outcomes.

OBJECTIVE

To explore women's experience of PCOS management and identify the relevant facilitators and barriers to management.

SEARCH STRATEGY

A structured search was undertaken in five bibliographic databases (MEDLINE, Web of Science, CINAHL, Embase, PubMed, and Cochrane) from the date of establishment of the database up to December 2022.

SELECTION CRITERIA

All qualitative and mixed-methods studies available in English describing the experience of PCOS management from the patients' perspective were included.

DATA COLLECTION AND ANALYSIS

The Joanna Briggs Institute Qualitative Assessment and Review Instrument was used to appraise study quality. The evidence was synthesized using a pragmatic meta-aggregative approach guided by the capability, opportunity, and motivation model of behavior (COM-B).

MAIN RESULTS

A total of 13 studies were included with 85 equivocal findings and 12 credible findings. The findings were meta-aggregated into three themes: (1) capability of women with PCOS, including patients' attitudes toward disease and management, knowledge, and skills of the disease; (2) opportunities in PCOS management, including information about PCOS, diagnostic delay, disease characteristics, disease management plan, and logistical and environmental problems; and (3) motivation in PCOS management, including impact of symptoms, perceived needs, support and feedback, and unpleasant medical experience.

CONCLUSIONS

This study identifies facilitators and barriers to PCOS management from the patient perspective, which can guide the design and implementation of PCOS management programs for patients. This study also provides information for future research into how the COM-B theory can be incorporated into specific management plans to promote patient action.

Long-term health risk of offspring born from assisted reproductive technologies

Since the world's first in vitro fertilization baby was born in 1978, there have been more than 8 million children conceived through assisted reproductive technologies (ART) worldwide, and a significant proportion of them have reached puberty or young adulthood. Many studies have found that ART increases the risk of adverse perinatal outcomes, including preterm birth, low birth weight, small size for gestational age, perinatal mortality, and congenital anomalies. However, data regarding the long-term outcomes of ART offspring are limited. According to the developmental origins of health and disease theory, adverse environments during early life stages may induce adaptive changes and subsequently result in an increased risk of diseases in later life. Increasing evidence also suggests that ART offspring are predisposed to an increased risk of non-communicable diseases, such as malignancies, asthma, obesity, metabolic syndrome, diabetes, cardiovascular diseases, and neurodevelopmental and psychiatric disorders. In this review, we summarize the risks for long-term health in ART offspring, discuss the underlying mechanisms, including underlying parental infertility, epigenetic alterations, non-physiological hormone levels, and placental dysfunction, and propose potential strategies to optimize the management of ART and health care of parents and children to eliminate the associated risks. Further ongoing follow-up and research are warranted to determine the effects of ART on the long-term health of ART offspring in later life.

Endometrial preparation protocols prior to frozen embryo transfer - convenience or safety?

The number of frozen embryo transfer (FET) cycles is increasing rapidly worldwide. Different endometrial preparations for FET result in comparable live birth rates. However, several recent publications have reported higher maternal risks for hypertensive disorders of pregnancy (HDP), pre-eclampsia and postpartum haemorrhage (PPH) in programmed cycles (PC-FET) compared with natural cycles and modified natural cycles with an intact corpus luteum. Nevertheless, PC-FET is frequently used in ovulatory women despite the increased risks for HDP, pre-eclampsia and PPH. Although randomized controlled studies have been suggested, PC-FET raises several methodological problems. Large study populations would be required to investigate the outcomes in question, and the inclusion of ovulatory women, where the intervention may increase the risk of a negative outcome, is ethically troublesome. In the authors' opinion, the existing evidence from large observational studies and systematic reviews is sufficiently strong to recommend an endometrial preparation strategy that aims to maintain or stimulate the corpus luteum to minimize the risk of HDP and pre-eclampsia after FET cycles.

Letrozole use in vitrified single-blastocyst transfer cycles is associated with lower risk of large for gestational age infants in patients with polycystic ovary syndrome

PURPOSE

To evaluate the obstetric and perinatal outcomes of three routine endometrial preparation protocols in women with PCOS who underwent frozen embryo transfer (FET).

METHODS

This was a retrospective study in women with PCOS who underwent FET in an academic reproductive medical center. A total of 2710 cycles were enrolled and classified into three groups according to different endometrial preparation protocols; human menopausal gonadotropin (HMG), letrozole + HMG, or hormone replacement therapy (HRT).

RESULTS

The stimulation groups had reduced risks of hypertensive disorders of pregnancy (HDP), large for gestational age (LGA) infants, and cesarean delivery than the HRT group. After adjustment for different confounder combinations in the two models, the frequencies of LGA and HDP in the letrozole + HMG group and the HMG group were still significantly lower than those in the HRT group. The letrozole + HMG group exhibited a reduced risk of LGA than HMG group after adjustment of confounders. A trend toward risk reductions in HDP and LGA was observe in turns of HRT, HMG, and letrozole + HMG groups, and the trends were statistically significant (Ptrend = 0.031 and 0.001).

CONCLUSION

In patients with PCOS, ovarian stimulation protocols for endometrial preparation are associated with reduced risks of HDP and LGA compared to HRT cycles. The use of letrozole could further reduce risk of LGA compared to HMG only protocol. We propose that ovarian stimulation protocols can be used widely for endometrial preparation in FET cycles in women with PCOS, especially with the use of letrozole.

Letrozole-stimulated endometrial preparation protocol is a superior alternative to hormone replacement treatment for frozen embryo transfer in women with polycystic ovary syndrome, a cohort study

BACKGROUND

The current routine endometrial preparation protocol for women with polycystic ovary syndrome (PCOS) is hormone replacement treatment (HRT). Letrozole is rarely used in frozen embryo cycles. Evidence confirming whether letrozole-stimulated (LS) protocol is suitable for frozen embryo transfer in patients with PCOS and for whom is suitable remains lacking.

METHODS

This was a retrospective cohort study involving all frozen embryo transfer cycles with LS and HRT for PCOS during the period from Jan 2019 to December 2020 at a tertiary care center. Multivariate Logistic regression was used to analyze the differences in clinical pregnancy rate, live birth rate, miscarriage rate, the incidence of other pregnancy and obstetric outcomes between LS and HRT protocols after adjusting for possible confounding factors. Subgroup analysis was used to explore the population for which LS protocol was suitable.

RESULTS

The results of multivariate logistic regression showed that LS was significantly associated with a higher clinical pregnancy rate (70.9% vs. 64.4%;aOR:1.41, 95%CI: 1.18,1.68), live birth rate (60.5% vs. 51.4% aOR:1.49, 95%CI: 1.27,1.76), and a lower risk of miscarriage (14.7% vs. 20.1% aOR: 0.68, 95%CI: 0.53,0.89), hypertensive disorders of pregnancy (6.7% vs. 8.9% aOR: 0.63, 95%CI: 0.42,0.95), and gestational diabetes mellitus (16.7% vs. 20.7% aOR:0.71, 95%CI: 0.53,0.93) than HRT. There were no significant differences in other outcomes such as preterm birth, cesarean delivery, small for gestational age, or large for gestational age between the two endometrial preparation protocols. Subgroup analysis showed that LS had higher live birth rates than HRT in most of the subgroups; in the three subgroups of maternal age ≥ 35 years, menstrual cycle < 35 days, and no insulin resistance, the live birth rates of the two endometrial preparation protocols were comparable.

CONCLUSIONS

LS protocol could improve the live birth rate and reduce the incidence of miscarriage, hypertensive disorders of pregnancy and gestational diabetes mellitus in patients with PCOS. LS protocol is suitable for all types of patients with PCOS. LS should be considered the preferred endometrial preparation protocol for women with PCOS.

First-trimester serum antiphosphatidylserine antibodies serve as candidate biomarkers for predicting pregnancy-induced hypertension

OBJECTIVE

The aim of this study was to explore whether antiphosphatidylserine (aPS) antibodies play roles in the early prediction of pregnancy-induced hypertension (PIH).

METHODS

The serum levels of different isotypes of aPS antibodies were compared in women diagnosed with PIH (PIH group, n  = 30) and 1 : 1 matched normotensive controls (control group, n  = 30). All patients underwent frozen embryo transfer (FET) cycles, and all serum samples were collected during 11-13 weeks of gestation. Receiver operating characteristic (ROC) curves were drawn to analyze the predictive values of aPS antibodies for PIH.

RESULTS

The women who developed PIH after FET had higher serum optical density values (450 nm) of aPS immunoglobulin (Ig) A (1.31 ± 0.43 vs. 1.02 ± 0.51, P  = 0.022), aPS IgM (1.00 ± 0.34 vs. 0.87 ± 0.18, P  = 0.046), and aPS IgG (0.50 ± 0.12 vs. 0.34 ± 0.07, P  < 0.001) compared with the normotensive controls. The serum concentration of total IgG [48.29 ± 10.71 (g/dl) vs. 34.39 ± 11.62 (g/dl), P  < 0.001] was also higher in the PIH group compared with that in the control group. The aPS IgG alone [area under the curve (AUC): 0.913, 95% confidence interval (CI): 0.842-0.985, P  < 0.001] and the combined analysis of aPS IgA, aPS IgM, aPS IgG, and total IgG (AUC: 0.944, 95% CI: 0.888-1.000, P  < 0.001) had high predictive values for PIH.

CONCLUSION

Serum aPS autoantibody levels during the first trimester of pregnancy are positively associated with the development of PIH. Further validation is needed to clearly identify the distinct contributions and underlying mechanisms for diagnostic applications of aPS autoantibodies in PIH prediction.

Live birth after letrozole-stimulated cycles versus hormone replacement treatment cycles for the first frozen embryo transfer in women with polycystic ovary syndrome: protocol for a multicentre randomised controlled trial

INTRODUCTION

Hormone replacement treatment (HRT) is the most commonly used endometrial preparation protocol for frozen embryo transfer (FET) in patients with polycystic ovary syndrome (PCOS). However, studies have found that HRT may increase the risk of hypertensive disorders of pregnancy and some obstetric complications. Letrozole is a new first-line ovulation induction drug for PCOS and can effectively induce spontaneous ovulation by reducing oestrogen levels. However, letrozole is still rarely used in FET and has only been reported in a few studies in Asian populations. High-quality, well-powered randomised controlled trials (RCTs) comparing HRT and letrozole-stimulated protocols are lacking. The aim of this study is to compare the efficacy and safety of two protocols in patients with PCOS.

METHODS AND ANALYSIS

This is a multicentre, open-label RCT in four reproductive medical centres in China. In total, 1078 women with PCOS will be randomised (1:1) to the letrozole-stimulated or HRT group in their first FET cycle and their pregnancy and perinatal outcomes during this cycle will be followed up and analysed. The primary outcome is live birth. Secondary outcomes are cycle cancellation rate, biochemical pregnancy, clinical pregnancy, miscarriage, ectopic pregnancy, obstetric and perinatal complications, neonatal complications and birth weight.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Institutional Review Board of Reproductive and Genetic Hospital of CITIC-XIANGYA (LL-SC-2022-001). Written informed consent will be obtained from each participant. The findings will be disseminated through conference presentations and publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05227391.

Reproductive and Obstetric Outcomes Following a Natural Cycle vs. Artificial Endometrial Preparation for Frozen-Thawed Embryo Transfer: A Retrospective Cohort Study

Background: The proportion of frozen embryo transfer cycles has consistently grown in recent decades. Some adverse obstetric outcomes after frozen embryo transfer could possibly be explained by different approaches in endometrial preparation. The aim of the present study was to investigate reproductive and obstetric outcomes after frozen embryo transfer, comparing different endometrial preparation strategies. Methods: This retrospective study included 317 frozen embryo transfer cycles, of which 239 had a natural or modified natural cycle and 78 underwent artificial endometrial preparation. After excluding late abortion and twin pregnancies, the outcomes of 103 pregnancies were analyzed, 75 of which were achieved after a natural cycle/modified natural cycle, and 28 were achieved after an artificial cycle. Results: The overall clinical pregnancy rate/embryo transfer was 39.7%, the miscarriage rate was 10.1%, and the live birth rate/embryo transfer was 32.8%, without significant differences in reproductive outcomes between natural/modified cycle and artificial cycle groups. The risks of pregnancy-induced hypertension and abnormal placental insertion were significantly increased in pregnancies achieved after the artificial preparation of the endometrium (p = 0.0327 and =0.0191, respectively). Conclusions: Our study encourages the use of a natural cycle or modified natural cycle for endometrial preparation for frozen embryo transfer in order to ensure the presence of a corpus luteum able to orchestrate maternal adaptation to pregnancy.

Higher risk of pre-eclampsia and other vascular disorders with artificial cycle for frozen-thawed embryo transfer compared to ovulatory cycle or to fresh embryo transfer following in vitro fertilization

Background

Risks of maternal morbidity are known to be reduced in pregnancies resulting from frozen embryo transfer (FET) compared to fresh-embryo transfer (fresh-ET), except for the risk of pre-eclampsia, reported to be higher in FET pregnancies compared to fresh-ET or natural conception. Few studies have compared the risk of maternal vascular morbidities according to endometrial preparation for FET, either with ovulatory cycle (OC-FET) or artificial cycle (AC-FET). Furthermore, maternal pre-eclampsia could be associated with subsequent vascular disorders in the offspring.

Methods

A 2013-2018 French nationwide cohort study comparing maternal vascular morbidities in 3 groups of single pregnancies was conducted: FET with either OC or AC preparation, and fresh-ET. Data were extracted from the French National Health System database. Results were adjusted for maternal characteristics and infertility (age, parity, smoking, obesity, history of diabetes or hypertension, endometriosis, polycystic ovary syndrome and premature ovarian insufficiency).

Results

A total of 68025 single deliveries were included: fresh-ET (n=48152), OC-FET (n=9500), AC-FET (n=10373). The risk of pre-eclampsia was higher in AC-FET compared to OC-FET and fresh-ET groups in univariate analysis (5.3% vs. 2.3% and 2.4%, respectively, P<0.0001). In multivariate analysis the risk was significantly higher in AC-FET compared to fresh-ET: aOR=2.43 [2.18-2.70], P<0.0001). Similar results were observed for the risk of other vascular disorders in univariate analysis (4.7% vs. 3.4% and 3.3%, respectively, P=0.0002) and in multivariate analysis (AC-FET compared to fresh-ET: aOR=1.50 [1.36-1.67], P<0.0001). In multivariate analysis, the risk of pre-eclampsia and other vascular disorders were comparable in OC-FET and fresh-ET: aOR=1.01 [0.87-1.17, P= 0.91 and aOR=1.00 [0.89-1.13], P=0.97, respectively).Within the group of FET, the risks of pre-eclampsia and other vascular disorders in multivariate analysis were higher in AC-FET compared to OC-FET (aOR=2.43 [2.18-2.70], P<0.0001 and aOR=1.5 [1.36-1.67], P<0.0001, respectively).

Conclusion

This nationwide register-based cohort study highlights the possibly deleterious role of prolonged doses of exogenous estrogen-progesterone supplementation on gestational vascular pathologies and the protective role of the corpus luteum present in OC-FET for their prevention. Since OC-FET has been demonstrated not to strain the chances of pregnancy, OC preparation should be advocated as first-line preparation in FET as often as possible in ovulatory women.

Transvaginal needle versus laparoscopic ovarian drilling in hormonal profile and pregnancy outcomes of polycystic ovary syndrome: a systematic review and meta-analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) is a prevalent hormonal disorder distinguished by a persistent absence of ovulation. Ovarian drilling is a recognized therapeutic approach for PCOS patients who are unresponsive to medication and can be performed through invasive laparoscopic access or less-invasive transvaginal access. The aim of this systematic review and meta-analysis was to assess the efficacy of transvaginal ultrasound -guided ovarian needle drilling with conventional laparoscopic ovarian drilling (LOD) in patients with PCOS.

METHODS

PUBMED, Scopus, and Cochrane databases were systematically searched for eligible randomized controlled trials (RCTs) from articles published from inception to January 2023. We include RCTs of PCOS that compared transvaginal ovarian drilling and LOD and reported on ovulation and pregnancy rates as the main outcome variable. We evaluated study quality using the Cochrane Risk of bias 2 tool. A random-effects meta-analysis was performed and the certainty of the evidence was assessed according to the GRADE approach. We registered the protocol prospectively in PROSPERO (CRD42023397481).

RESULTS

Six RCTs including 899 women with PCOS met the inclusion criteria. LOD was found to significantly reduce anti-Mullerian hormone (AMH) (SMD: -0.22; 95% CI: -0.38, -0.05; I² = 39.85%) and antral follicle count (AFC) (SMD: -1.22; 95% CI: -2.26, -0.19; I² = 97.55%) compared to transvaginal ovarian drilling. Our findings also indicated that LOD significantly increased the ovulation rate by 25% compared to transvaginal ovarian drilling (RR: 1.25; 95% CI: 1.02, 1.54; I2 = 64.58%). However, we found no significant difference between the two groups in terms of follicle stimulating hormone (SMD: 0.04; 95% CI: -0.26, 0.33; I2 = 61.53%), luteinizing hormone (SMD: -0.07; 95% CI: -0.90, 0.77; I2 = 94.92%), and pregnancy rate (RR: 1.37; 95% CI: 0.94, 1.98; I2 = 50.49%).

CONCLUSION

LOD significantly lowers circulating AMH and AFC and significantly increases ovulation rate in PCOS patients compared to transvaginal ovarian drilling. As transvaginal ovarian drillingremains a less-invasive, more cost-effective, and simpler alternative, further studies are warranted to compare these two techniques in large cohorts, with a particular focus on ovarian reserve and pregnancy outcomes.

The future of frozen-thawed embryo transfer in hormone replacement therapy cycles

PURPOSE OF REVIEW

This review focuses on the efficacy of letrozole stimulated frozen-thawed embryo transfer (FET) compared to hormone replacement therapy (HRT) FET in women with polycystic ovarian syndrome (PCOS) and/or oligo-anovulation. Further, obstetric and perinatal risks in HRT FET are summarized.

RECENT FINDINGS

The presence of a corpus luteum seems to reduce the risk of pregnancy-related hypertension and preeclampsia after FET. As a natural cycle (NC) FET is not an option for women with oligo-/amenorrhea these women may benefit from FET with mild stimulation compared to HRT FET. The intention of mild stimulation in anovulatory women is to induce (mono) ovulation to mimic the endocrine profiles of the natural cycle and the early pregnancy after natural conception. Mild stimulation by letrozole is patient friendly and cheap compared to gonadotropin stimulated FET and has been increasingly used in recent years. Although the quality of evidence is low, the pregnancy outcomes after letrozole FET seems similar or even better compared to HRT FET in women with PCOS and/or oligo-anovulation.

SUMMARY

Natural and modified NC FET should be used whenever possible to mitigate adverse obstetric and perinatal outcomes after HRT FET. For anovulatory women, whenever ovulation can be induced, we advocate the use of mild stimulation FET to create a corpus luteum awaiting results from RCTs limited to oligo-anovulatory women.

Gonadotropins as pharmacological agents in assisted reproductive technology and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a complex endocrinopathy associated with subfertility/infertility and pregnancy complications. Most PCOS women opt for assisted reproductive technologies (ART) for successful conception; however, optimization of the relative doses of the gonadotropins [follicle-stimulating hormone (FSH), luteinizing hormone (LH)/human chorionic gonadotropin (hCG)] for appropriate steroidogenesis, without causing ovarian hyperstimulatory syndrome (OHSS), is challenging. Embryonic factors probably do not contribute to pregnancy loss in PCOS women, albeit hormonal imbalance impairs the metabolic microenvironment critical for oocyte maturation and endometrial receptivity. Certain clinical studies have confirmed the role of metabolic corrections in increasing the rate of pregnancy in PCOS women. This review focuses on the impact of untimely high LHCGR and/or LH levels on oocyte/embryo quality, pregnancy outcomes in ART, and exploring LHCGR as a potential drug target in PCOS women.

Comparison of pregnancy outcomes of letrozole-induced frozen-thawed embryo transfer cycles in PCOS women with two different abnormal ovulation patterns: A retrospective cohort study

No studies have been conducted on the impact of different types of ovulatory dysfunction on the outcomes of frozen-thawed embryo transfers (FETs) in a letrozole-stimulated cycle in women with polycystic ovarian syndrome (PCOS). This study aimed to compare whether pregnancy outcomes of the letrozole-induced protocol in FET cycles differed between oligo-ovulatory and anovulatory women with PCOS. In a retrospective cohort study, women with PCOS who had undergone letrozole-induced FET at a university-affiliated fertility clinic from February 2014 to October 2020 were identified. The primary end point was live birth rate (LBR) per embryo transfer. Propensity score matching and multivariate logistic regression analyses were performed to control for the relevant confounders. A total of 652 women with PCOS undergoing letrozole-induced FET were included in the final analysis. Three hundred sixty-three of these women had oligo-ovulatory periods, while 289 had anovulatory periods. Propensity score matching analysis showed that LBR did not differ between groups (36.8% in oligo-ovulatory group vs 32.8% in anovulatory group, P = .431). Nevertheless, after controlling for potential confounding factors, LBR was significantly lower in anovulatory than oligo-ovulatory women (adjusted odds ratio 1.57, 95% confidence interval 1.08-2.29, P = .018). Furthermore, the pregnancy loss rate among the oligo-ovulatory group remained lower than those among the anovulatory group (adjusted odds ratio 0.23, 95% confidence interval 0.12-0.44, P < .001). Despite adjustment for confounding factors, those with oligo-ovulatory PCOS had a higher LBR and lower pregnancy loss rate compared with those with anovulatory PCOS. This may indicate that when oligo-ovulation is detected, PCOS patients should be intervened in time to conceive as soon as possible. Prospective studies must be conducted in the future to verify our findings.

Impact of different endometrial preparation protocols before frozen embryo transfer on pregnancy outcomes: a review

The use of frozen embryo transfer cycles has exponentially increased in the last few years. Optimization of endometrial preparation protocols before frozen embryo transfer is mandatory to further improve pregnancy outcomes. This review will focus on the existing literature with regard to the different available endometrial preparation protocols and their impact on pregnancy outcomes. More specifically, we will focus on programmed, natural, and stimulated frozen embryo transfer cycles. The studies performed on this topic are generally of low quality, and only a few well-performed randomized controlled trials have been published. To date, no strong evidence is available to support the use of 1 preparation method over another in terms of pregnancy outcomes. However, robust data have shown a clearly protective effect of natural frozen embryo transfer cycles against long-term obstetric complications, mainly hypertensive disorders of pregnancy and large for gestational age infants. The introduction of individualized luteal phase support in different endometrial preparation protocols is actually gaining a lot of attention and requires further investigation.

Association between Pre-Pregnancy Overweightness/Obesity and Pregnancy Outcomes in Women with Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis

Polycystic ovary syndrome (PCOS) is a common metabolic problem in women of reproductive age. Evidence suggests pregnant women with PCOS may have a higher risk of the development of adverse pregnancy outcomes; however, the relationship between pre-pregnancy overweight/obesity and pregnancy outcomes in women with PCOS remains uncertain. We try to clarify the relationship between pre-pregnancy overweight/obesity and subsequent pregnancy outcomes. Therefore, we conducted this systematic review and meta-analysis. We used the databases obtained from the PubMed, Embase, Web of Science, and Cochrane databases, plus hand-searching, to examine the association between pre-pregnancy overweightness/obesity and pregnancy outcomes in women with PCOS from inception to 4 February 2022. A total of 16 cohort studies, including 14 retrospective cohort studies (n = 10,496) and another two prospective cohort studies (n = 818), contributed to a total of 11,314 women for analysis. The meta-analysis showed significantly increased odds of miscarriage rate in PCOS women whose pre-pregnancy body mass index (BMI) is above overweight (OR 1.71 [95% CI 1.38–2.11]) or obese (OR 2.00 [95% CI 1.38–2.90]) under a random effect model. The tests for subgroup difference indicated the increased risk was consistent, regardless which body mass index cut-off for overweight (24 or 25 kg/m²) or obesity (28 and 30 kg/m²) was used. With the same strategies, we found that pregnant women in the control group significantly increased live birth rate compared with those pregnant women with PCOS as well as pre-pregnancy overweight/obesity (OR 0.79 [95% CI 0.71–0.89], OR 0.78 [95% CI 0.67–0.91]). By contrast, we did not find any association between PCOS women with pre-pregnancy overweight/obesity and preterm birth. Based on the aforementioned findings, the main critical factor contributing to a worse pregnancy outcome may be an early fetal loss in these PCOS women with pre-pregnancy overweight/obesity. Since PCOS women with pre-pregnancy overweightness/obesity were associated with worse pregnancy outcomes, we supposed that weight reduction before attempting pregnancy in the PCOS women with pre-pregnancy overweightness/obesity may improve the subsequent pregnancy outcomes.

Ovulation induction regimens are associated with a higher rate of livebirth after frozen single-blastocyst transfer among women with polycystic ovary syndrome

BACKGROUND

Hormone replacement therapy (HRT) regimen was suggested to be associated with a decreased rate of livebirth and a higher risk of hypertensive disorders of pregnancy (HDP) after frozen cleavage stage embryo transfer in women with polycystic ovary syndrome (PCOS). With the dramatically increased use of elective single embryo transfer, there is great need to explore the impacts of different endometrial preparation regimens on frozen single-blastocyst transfer in women with PCOS.

METHODS

In this study, a total of 3941 women who diagnosed with PCOS and underwent single-blastocyst transfer during their first cycles of frozen embryo transfer (FET) between March 2012 and December 2020 were included. We retrospectively compared the pregnancy and neonatal outcomes after frozen single-blastocyst transfer with endometrial preparation by HRT regimen (n = 3540), ovulation induction by human menopausal gonadotropin (hMG) regimen (n = 226), and ovulation induction by letrozole regimen (n = 175).

RESULTS

After adjustment for confounders with multivariable logistic regression, the hMG regimen group [(58.4% vs. 49.6%; adjusted odds ratio (aOR): 1.43; 95% confidence interval (CI): 1.09-1.89)] and letrozole regimen group (58.9% vs. 49.6%; aOR: 1.42; 95% CI: 1.04-1.93) were associated with a higher rate of livebirth (primary outcome), compared with the group with HRT regimen. As to the secondary outcomes, the rate of pregnancy loss in the hMG regimen group (22.8% vs. 30.3%; aOR: 0.69; 95% CI: 0.48-1.00) and letrozole regimen group (16.9% vs. 30.3%; aOR: 0.48; 95% CI: 0.30-0.78) was also lower than that in the HRT regimen group. The pregnancy outcomes between the hMG regimen group and the letrozole regimen group were similar. We did not observe significant difference in the incidences of maternal and neonatal complications among these three groups.

CONCLUSION

Ovulation induction regimen with letrozole or hMG for endometrial preparation was associated with a higher livebirth rate and a lower pregnancy loss rate in frozen single-blastocyst transfer cycles among women with PCOS.