The Effect of Supraphysiological Estradiol on Pregnancy Outcomes Differs Between Women With PCOS and Ovulatory Women

Paternal age does not jeopardize the live birth rate and perinatal outcomes after in vitro fertilization: an analysis based on 56,113 frozen embryo transfer cycles

BACKGROUND

The global trend of delaying childbearing has led to an increasing number of couples seeking in vitro fertilization. The adverse effects of advanced maternal age on pregnancy and perinatal outcomes are well documented, regardless of the conception method. In addition, advanced paternal age may contribute to poor reproductive potential because of high levels of sperm DNA fragmentation. However, it remains challenging to guide older men regarding the effect of paternal age on pregnancy and birth outcomes in the field of assisted reproduction.

OBJECTIVE

This study aimed to investigate the association of paternal age with live birth and perinatal outcomes following in vitro fertilization-frozen embryo transfer.

STUDY DESIGN

A retrospective study was performed at a university-affiliated fertility center, involving women who were younger than 36 years and had undergone frozen embryo transfer from January 2011 to June 2021. Subjects were categorized into 6 groups based on paternal age: <25, 25 to 29, 30 to 34, 35 to 39, 40 to 44, and ≥45 years. A generalized estimating equation logistic regression model was used to account for the clustered nature of data and to adjust for confounders. Paternal age between 25 and 29 years served as the reference group in the logistic regression models.

RESULTS

A total of 56,113 cycles who met the inclusion criteria were included in the final analysis. On unadjusted analyses, the reproductive outcome parameters showed a considerable decline with increasing male age. The live birth rate decreased from 47.9% for men aged 25 to 29 years to 40.3% among men aged ≥40 years. Similarly, the clinical pregnancy rate decreased from 54.4% in the reference group to 47.8% in the ≥40 years age group. Conversely, the miscarriage rate increased as male age increased, from 10.2% among men aged 25 to 29 years to 13.5% among men aged ≥45 years. However, the differences in the reproductive outcomes mentioned above were no longer significant in the multivariable models. Compared with the younger controls, advanced paternal age was not associated with a lower chance of live birth (males aged 40-44 years: adjusted odds ratio, 0.94; 95% confidence interval, 0.85-1.04; males aged ≥45 years: adjusted odds ratio, 0.93; 95% confidence interval, 0.79-1.10). In addition, the rates of clinical pregnancy (males aged 40-44 years: adjusted odds ratio, 0.95; 95% confidence interval, 0.85-1.05; males aged ≥45 years: adjusted odds ratio, 0.94; 95% confidence interval, 0.79-1.12) and miscarriage (males aged 40-44 years: adjusted odds ratio, 1.05; 95% confidence interval, 0.85-1.31; males aged ≥45 years: adjusted odds ratio, 1.07; 95% confidence interval, 0.77-1.50) were comparable between the reference and advanced paternal age groups. Furthermore, men in the youngest age group (<25 years) did not have worse pregnancy outcomes than those in the reference group. Regarding perinatal outcomes, there was no difference among the study cohorts in terms of preterm birth, low birthweight, macrosomia, small for gestational age, and large for gestational age, both in the unadjusted and confounder-adjusted models.

CONCLUSION

This study did not demonstrate a significant association between paternal age and live birth and perinatal outcomes after in vitro fertilization-frozen embryo transfer when the female partners were younger than 36 years. With the global trend toward delaying childbirth, our findings provide useful information for counseling patients that increasing paternal age may not adversely affect pregnancy and perinatal outcomes in assisted reproduction.

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.

Association between serum LH levels on hCG trigger day and live birth rate after fresh embryo transfer with GnRH antagonist regimen in different populations

Objective

To investigate whether serum LH levels on hCG trigger day are associated with live birth rate (LBR) after fresh embryo transfer with GnRH antagonist regimen in different populations.

Methods

This study was a retrospective study. A total of 3059 fresh embryo transfers were divided into three populations: predicted normal ovarian responders (NOR) (n=2049), patients with PCOS (n=533), and predicted poor ovarian responders (POR) (n=477). Each population was stratified into three groups based on LH levels: < 25th percentile, 25-75th percentile, and > 75th percentile. The primary outcome of the study was LBR, and secondary outcomes included implantation, clinical pregnancy, and early pregnancy loss rates. Univariable and multivariable regression analyses were performed to adjust for potential confounders.

Results

In NOR, compared to the reference group (>75th percentile), LBR was significantly lower in the < 25th percentile group (adjusted OR=0.662; 95%CI, 0.508-0.863) and 25-75th percentile group (adjusted OR=0.791; 95%CI, 0.633-0.988). In PCOS patients, LBR decreased significantly in the < 25th percentile group (41.4%) compared to the 25-75th percentile group (53.7%) and > 75th percentile group (56.1%). In addition, the LBR was lower in the < 25th percentile group (33.6%) compared with the 25-75th percentile group (43.4%) and the>75th percentile group (42.0%) in POR, but this was not statistically significant.

Conclusions

High serum LH levels are associated with increased LBR after fresh embryo transfer in GnRH antagonist cycles, which may be attributable to higher implantation rate. LH may be a predictor of whether to schedule fresh embryo transfer in IVF cycles for better clinical outcomes.

Risk factors for clinical pregnancy loss after IVF in women with PCOS

RESEARCH QUESTION

Which factors are associated with the risk of clinical pregnancy loss in women with polycystic ovary syndrome (PCOS) undergoing IVF?

DESIGN

Case-control study nested in a multicentre randomized trial comparing live birth rates between fresh and frozen embryo transfer in women with PCOS. Women with the outcome of clinical pregnancy loss were selected as the case group, those with live birth as the control group. Parameters before IVF treatment and variables during ovarian stimulation and embryo transfer were compared.

RESULTS

Women with clinical pregnancy loss had higher maternal body mass index (BMI, P = 0.010), anti-Müllerian hormone (AMH, P = 0.032), 2-h glucose concentration after 75 g oral glucose tolerance test (OGTT, P = 0.025), and a higher proportion of fresh embryo transfers (P = 0.001). There were significant interactions between the types of transfer and antral follicle count (AFC, P = 0.013), 2-h glucose concentration after OGTT (P = 0.024) on clinical pregnancy loss in PCOS, indicating that these factors may have different effects on pregnancy loss after fresh versus frozen embryo transfer. When the multivariable logistic regression analysis was stratified by the fresh or frozen embryo transfer, AFC (adjusted odds ratio [aOR] 1.03, 95% confidence interval [CI] 1.01-1.05) was a risk factor for clinical pregnancy loss after fresh embryo transfer, while 2-hour glucose concentration after OGTT (aOR 1.13, 95% CI 1.01-1.25) was associated with clinical pregnancy loss in frozen embryo transfer (FET) cycles.

CONCLUSIONS

In women with PCOS, fresh embryo transfer, higher BMI, AFC and 2-h glucose concentration after OGTT were risk factors for clinical pregnancy loss. FET may be a better choice to decrease the risk of clinical pregnancy loss, especially for those with higher AFC. During FET, 2-h glucose after OGTT appears to be associated with clinical pregnancy loss and warrants close monitoring.

Comparison of Clinical Pregnancy Outcomes after Fresh and Frozen Embryo Transfer

Objectives. To analyze the clinical outcomes of the patients who underwent fresh or frozen embryo transfer, as well as the neonatal outcomes. Methods. We conducted a retrospective analysis of women who underwent in vitro fertilization with fresh and frozen embryo transfer from January 2019 to January 2021. All of the included embryo transfers resulted in live births at ≥28 weeks of gestation. All of the patients were divided into two groups according to the assisted reproductive technique that was used (fresh embryo transfer group ( $n=101$ ) and frozen embryo transfer group ( $n=125$ )). Both groups were divided into subgroups based on a maternal age of ≥35 years. Result(s). Between the two groups, only the cesarean section rate was higher in the frozen transfer group, while no differences were shown for other outcomes. There were significant differences in the gestational hypertension and postpartum hemorrhage rates based on the subgroup comparison. No significant differences were detected in the offspring. Conclusions. Comparing fresh and frozen embryo transfers did not reveal any significant superiority. Venerable age exerts an apparent influence on pregnancy complications. Frozen embryo transfer is not always the best choice.

The Impact of Suppressing Estradiol During Ovarian Stimulation on the Unsupported Luteal Phase: A Randomized Controlled Trial

CONTEXT

Supraphysiological sex steroid levels at the follicular-luteal phase transition are implicated as the primary cause of luteal insufficiency after ovarian stimulation (OS) for in vitro fertilization.

OBJECTIVE

We aimed to determine the impact of suppressing estradiol levels during OS of multiple dominant follicles on the unsupported luteal phase and markers of endometrial maturation.

METHODS

At 2 university hospitals, 25 eligible egg donors were randomized to undergo OS using exogenous gonadotropins with or without adjuvant letrozole 5 mg/day. Final oocyte maturation was triggered with a GnRH agonist. No luteal support was provided. The primary outcome was the duration of the luteal phase. Secondary outcomes were luteal phase hormone profiles and the endometrial transcriptomic signature 5 days after oocyte pick up (OPU + 5).

RESULTS

The median (interquartile range [IQR]) luteal phase duration was 8.0 (6.8-11.5) days compared with 5.0 (5.0-6.8) days in the intervention and control group, respectively (P < 0.001). Estradiol levels were effectively suppressed in the letrozole group with a median of 0.86 (0.23-1.24) nmol/L at OPU compared to 2.82 (1.34-3.44) nmol/L in the control group. Median (IQR) progesterone levels at OPU + 5 were 67.05 (15.67-101.75) nmol/L in the letrozole group vs 2.27 (1.05-10.70) nmol/L in the control group (P < 0.001). In the letrozole group, 75% of participants revealed endometrial transcriptomic signatures interpreted as post-receptive. In the control group, 40% were post-receptive and 50% noninformative.

CONCLUSION

Suppressing estradiol levels in the follicular phase with adjuvant letrozole significantly reduces the disruption of the unsupported luteal phase after OS.

Comparison of two endometrial preparation methods for frozen-thawed embryo transfer in anovulatory PCOS patients: impact on miscarriage rate

OBJECTIVE

- Some studies have suggested that patients with polycystic ovary syndrome (PCOS) are at high risk of miscarriage. However, this still remains controversial. Several potential factors might explain this association: obesity, hyperinsulinemia and hyperandrogenism. Artificial and stimulated cycles appear to be comparable for endometrial preparation in frozen-thawed embryo transfer (FET) in PCOS patients. Only a few studies have assessed miscarriage rates specifically in PCOS. We have evaluated the impact of endometrial preparation on FET outcomes in anovulatory PCOS patients.

METHODS

- A retrospective cohort study was conducted at the Lille University Hospital, including 255 FET cycles in 134 PCOS patients between January 2011 and December 2017. PCOS was defined by the presence of at least two of the three Rotterdam's criteria. Patients were under 35 years old. Two endometrial preparation protocol were studied: stimulated cycle (gonadotropins on the second day of the cycle and luteal phase support including natural progesterone 600 mg/day) and artificial cycle (6 mg oral estradiol valerate and 800 mg micronized vaginal progesterone daily).

RESULTS

- 137 FET were performed under stimulated cycle and 118 FET under artificial cycle. Early pregnancy rates (30% versus 37.3%, p = NS), miscarriage rates (22% versus 25%, p = NS) and live birth rates (23.4% versus 26.3%, p = NS) were similar.

CONCLUSIONS

- In anovulatory PCOS women, the type of endometrial preparation does not influence FET outcomes, specifically regarding the miscarriage rate.

Placental sFlt-1 Gene Delivery in Early Primate Pregnancy Suppresses Uterine Spiral Artery Remodeling

Uterine spiral artery remodeling (SAR) is essential for promoting placental perfusion and fetal development. A defect in SAR results in placental ischemia and increase in placental expression and serum levels of the soluble fms-like tyrosine kinase-1 (sFlt-1) receptor that binds to and suppresses vascular endothelial growth factor (VEGF) bioavailability, thereby leading to maternal vascular dysfunction. We have established a nonhuman primate model of impaired SAR and maternal vascular dysfunction by prematurely elevating estradiol levels in early baboon pregnancy. However, it is unknown whether this primate model of defective SAR involves an increase in placental expression of sFlt-1, which may suppress VEGF bioavailability and thus SAR in the first trimester. Therefore, to establish the role of sFlt-1 in early pregnancy, SAR was quantified in baboons treated on days 25 through 59 of gestation (term = 184 days) with estradiol or with the sFlt-1 gene targeted selectively to the placental basal plate by ultrasound-mediated/microbubble-facilitated gene delivery technology. Placental basal plate sFlt-1 protein expression was 2-fold higher (P < 0.038) and the level of SAR for vessels > 25 µm in diameter was 72% and 63% lower (P < 0.01), respectively, in estradiol-treated and sFlt-1 gene-treated baboons than in untreated animals. In summary, prematurely elevating estradiol levels or sFlt-1 gene delivery increased placental basal plate sFlt-1 protein expression and suppressed SAR in early baboon pregnancy. This study makes the novel discovery that in elevated levels sFlt-1 has a role both in suppressing SAR in early primate pregnancy and maternal vascular endothelial function in late gestation.

The Optimal Number of Oocytes Retrieved From PCOS Patients Receiving IVF to Obtain Associated With Maximum Cumulative Live Birth Rate and Live Birth After Fresh Embryo Transfer

AIMS

This study aims to determine the optimal number of oocytes retrieved so that patients with polycystic ovary syndrome (PCOS) receiving in vitro fertilization (IVF) can obtain the best cumulative live birth rate (CLBR) and live birth after fresh embryo transfer.

METHODS

This is a retrospective study of 1,419 patients with PCOS who underwent their first IVF cycle at the Second Hospital of Hebei Medical University from January 2014 to December 2021. Multivariable regression analysis was performed to adjust for factors known to independently affect cumulative live birth aspiration. The number of oocytes retrieved to obtain the best cumulative live birth rate was explored through curve fitting and threshold effect analysis. The decision tree method was used to explore the best number of oocytes retrieved to achieve live birth in the shortest time.

RESULTS

(1) The number of oocytes retrieved was found to be an independent protective factor for the cumulative live birth rate (OR = 1.09 (95% CI: 1.06, 1.12)). When the number of oocytes retrieved was less than 15, CLBR increased by 16% with each increase in the number of oocytes retrieved (OR = 1.16 (95% CI: 1.11, 1.22)); and when more than 15, CLBR tended to be stable. (2) Live birth after the first fresh embryo transfer was analyzed through a classification decision tree. For patients younger than 35 years old, those with less than 6 oocytes and those with 7-16 oocytes had a similar proportion of live births with fresh embryo transfer but higher than 16 oocytes (53.7% vs. 53.8% vs. 18.4%). Patients older than 35 years old had a similar proportion of live births with fresh embryo transfer (35.7% vs. 39.0%) to those younger than 35 years old, but the proportion of no live births after using up all embryos was higher than those younger than 35 years old (39.3% vs. 19.2%).

CONCLUSIONS

In PCOS patients, high CLBR can be obtained when the number of oocytes retrieved was 15 or more. The number of oocytes retrieved from 7 to 16 could achieve more chance of live birth after fresh embryo transfer.

Comparison of Stimulated Cycles with Low Dose r-FSH versus Hormone Replacement Cycles for Endometrial Preparation Prior to Frozen-Thawed Embryo Transfer in Young Women with Polycystic Ovarian Syndrome: A Single-Center Retrospective Cohort Study from China

Objective

The principal purpose of this study was to compare reproductive outcomes for stimulated cycles (STC) and hormone replacement cycles (HRC) for endometrial preparation before frozen-thawed embryo transfer (FET) in young women with polycystic ovary syndrome (PCOS).

Methods

We conducted a retrospective study of 1434 FET cycles from January, 2017 to March, 2020 in our reproductive center, in which stimulated and hormone replacement cycles were used for endometrial preparation. Pregnancy outcomes of couples undergoing routine STC-FET or HRC-FET were analyzed by propensity score matching (PSM) and multivariable logistic regression analyses.

Results

Data on 1234 HRC protocols (86% of the total) and 200 STC protocols (14%) were collected. After PSM, 199 patients were included in both groups, respectively. There was no significant difference in positive pregnancy rate (52.7% vs 54.8%, p=0.763), clinical pregnancy rate (51.8% vs 52.8%, p=0.841), live birth rate (45.2% vs 43.7%, p=0.762), pregnancy loss rate (9.7% vs 16.2%, p=0.164) and ectopic pregnancy rate (1.5% vs 0.5%, p=0.615) between STC and HRC protocols. Subsequent multivariate logistic regression analysis also yielded similar results.

Conclusion

STC for endometrial preparation had similar pregnancy outcomes compared with HRC protocols. Evidence is available which shows that for young women with PCOS in preparation for FET, HRC could be a reasonable choice for patients who are unwilling to accept injections. However, STC may reduce unnecessary anxiety and operational costs and offer more flexibility for patients. Eventually, we must embrace the concepts of individualization, securitization, and optimization in the clinic.

The effect of different endometrial preparations on women with polycystic ovary syndrome undergoing initial frozen embryo transfer: A historical cohort analysis

INTRODUCTION

Frozen embryo transfer is associated with a higher rate of live birth and a lower risk for ovarian hyperstimulation syndrome in women with polycystic ovary syndrome (PCOS) compared with fresh embryo transfer. The aim of this study is to assess the optimal endometrial preparation protocol for women with PCOS undergoing frozen embryo transfer.

MATERIAL AND METHODS

We conducted a historical cohort analysis of 1720 women with PCOS who underwent the "freeze-all" strategy between August 2014 and August 2017 because of their high risk for ovarian hyperstimulation syndrome. Three endometrial preparation protocols were used: natural cycle (NC; n = 191), which relies on the dominant follicle to secrete estrogen that then promotes endometrial growth; ovarian stimulation (OS; n = 96), which induces follicle growth using low doses of human menopausal gonadotropin; and hormone replacement (HRT; n = 1433), which uses exogenous estradiol to promote endometrial growth. The primary outcome was live birth.

RESULTS

For women who received a single embryo transfer, the live birth rates for the NC, OS, and HRT groups were 62.4%, 65.0%, and 52.2%, respectively. The live birth rate in the HRT group was significantly lower than that seen in the OS and NC groups (P = .009). The clinical pregnancy rates of the three groups were 72.3%, 73.8%, and 64.9%, respectively; this difference did not reach statistical significance (P = .071).

CONCLUSIONS

The rate of live birth with the NC and OS regimens was higher than with the HRT protocol in women with PCOS who undergo single-blastocyst frozen embryo transfer.

Endometrial function in women with polycystic ovary syndrome: a comprehensive review

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. An endometrial component has been suggested to contribute to subfertility and poor reproductive outcomes in affected women.

OBJECTIVE AND RATIONALE

The aim of this review was to determine whether there is sufficient evidence to support that endometrial function is altered in women with PCOS, whether clinical features of PCOS affect the endometrium, and whether there are evidence-based interventions to improve endometrial dysfunction in PCOS women.

SEARCH METHODS

An extensive literature search was performed from 1970 up to July 2020 using PubMed and Web of Science without language restriction. The search included all titles and abstracts assessing a relationship between PCOS and endometrial function, the role played by clinical and biochemical/hormonal factors related to PCOS and endometrial function, and the potential interventions aimed to improve endometrial function in women with PCOS. All published papers were included if considered relevant. Studies having a specific topic/hypothesis regarding endometrial cancer/hyperplasia in women with PCOS were excluded from the analysis.

OUTCOMES

Experimental and clinical data suggest that the endometrium differs in women with PCOS when compared to healthy controls. Clinical characteristics related to the syndrome, alone and/or in combination, may contribute to dysregulation of endometrial expression of sex hormone receptors and co-receptors, increase endometrial insulin-resistance with impaired glucose transport and utilization, and result in chronic low-grade inflammation, immune dysfunction, altered uterine vascularity, abnormal endometrial gene expression and cellular abnormalities in women with PCOS. Among several interventions to improve endometrial function in women with PCOS, to date, only lifestyle modification, metformin and bariatric surgery have the highest scientific evidence for clinical benefit.

WIDER IMPLICATIONS

Endometrial dysfunction and abnormal trophoblast invasion and placentation in PCOS women can predispose to miscarriage and pregnancy complications. Thus, patients and their health care providers should advise about these risks. Although currently no intervention can be universally recommended to reverse endometrial dysfunction in PCOS women, lifestyle modifications and metformin may improve underlying endometrial dysfunction and pregnancy outcomes in obese and/or insulin resistant patients. Bariatric surgery has shown its efficacy in severely obese PCOS patients, but a careful evaluation of the benefit/risk ratio is warranted. Large scale randomized controlled clinical trials should address these possibilities.

Maternal and Neonatal Complications After Natural vs. Hormone Replacement Therapy Cycle Regimen for Frozen Single Blastocyst Transfer

Objective: To evaluate the maternal and neonatal complications after frozen-thawed blastocyst transfer cycles utilizing different endometrial preparation regimens.

Design: This is a retrospective cohort study and a secondary analysis of a multicenter, randomized, controlled trial comparing live birth rate after fresh vs. frozen single blastocyst transfer (Frefro-blastocyst).

Setting: Reproductive medicine centers.

Patient(s): A total of 800 women with regular menstrual cycles undergoing their first cycle of in-vitro fertilization after frozen-thawed single blastocyst transfer.

Intervention(s): Endometrium preparation was performed with a natural cycle regimen or hormone replacement therapy (HRT) cycle regimen, at the discretion of local investigators. All pregnancies were followed up until delivery.

Main Outcome Measure(s): Maternal and neonatal complications.

Result(s): 513 infertile patients who underwent natural cycles regimen and 287 who underwent HRT cycles regimen were analyzed. The incidences of maternal and neonatal complications were comparable between the natural cycle and HRT cycle regimen. Regarding the risk of gestational diabetes, gestational hypertension, pre-eclampsia, preterm delivery, small for gestational age and large for gestational age, the HRT cycle was still not a significant risk factor after adjusting for potential confounders. The natural cycle regimen yielded an insignificant higher total live birth rate [59.45 vs. 50.17%, P = 0.001, adjusted odds ratio (AOR) 1.366, 95% confidence interval (CI) 0.975–1.913], clinical pregnancy rate (68.23 vs. 58.89%, P = 0.008, AOR 1.406, 95% CI 0.992–1.991) and ongoing pregnancy rate (62.18 vs. 52.61%, P = 0.008, AOR 1.387, 95% CI 0.988–1.948) than did the HRT cycle regimen. However, compared to natural cycles, HRT cycles were associated with a significantly higher risk of biochemical miscarriage (6.86 vs. 18.18%, P < 0.001, AOR 0.328, 95% CI, 0.176–0.611).

Conclusion(s): The incidence of maternal and neonatal complications in natural cycle and HRT cycle regimens after frozen single blastocyst transfer were comparable. Frozen-thawed single blastocyst transfer in a natural cycle was associated with lower biomedical miscarriage than the use of the HRT cycle.

Clinical Trial Registration Number: Frefro-blastocyst was registered at Chinese Clinical Trial Registry, ChiCTR-IOR-14005405.

A comparison of IVF outcomes transferring a single ideal blastocyst in women with polycystic ovary syndrome and normal ovulatory controls

PURPOSE

To assess the effects PCOS on live birth rates when transferring a single fresh ideal blastocyst.

METHODS

A retrospective cohort study performed at the university-affiliated reproductive center. Women with PCOS and a control group of normal ovulatory women who underwent their first fresh embryo transfer with single ideal grade blastocyst were included in the study. Demographic, stimulation information and pregnancy outcomes were collected and analysed. The primary outcome was live birth rates, and secondary outcomes included pregnancy and clinical pregnancy rates.

RESULTS

71 Women with PCOS and 272 normal ovulatory controls underwent their first embryo transfer and met the inclusion and exclusion criteria. PCOS patient were younger (31.0 ± 3.7 vs. 33.1 ± 3.2, p = 0.0001), with higher AFC (40.0 ± 9.3 vs. 13.3 ± 4.6, p = 0.0001), required lower dose of gonadotropins to stimulate (1198 ± 786 vs. 1891 ± 1224, p = 0.0001), and had higher serum testosterone levels (2.3 ± 0.7 vs. 1.1 ± 0.3, p = 0.0001). No significant difference was found between the two groups regarding the number of previous pregnancies, the number of previous full-term pregnancies, the level of basal serum FSH, estradiol level at triggering and the BMI. When compared by Chi squared testing pregnancy rates, clinical pregnancy rates and live birth rates did not differ. However, when controlling (with multivariate stepwise logistic regression) for confounders, live birth rates were lower among the women with PCOS (p = 0.035, CI: 0.18-0.92).

CONCLUSION

After controlling for confounders, when transferring a fresh single ideal blastocyst, live birth rates were lower among the women with PCOS than normal ovulatory controls.

Hormone Replacement Versus Natural Cycle Protocols of Endometrial Preparation for Frozen Embryo Transfer

RESEARCH QUESTION

Endometrial preparation is one of the most important steps for ensuring frozen embryo transfer success. However, there is no clear evidence that identifies an optimal endometrial preparation protocol for frozen embryo transfer. In addition, in studies that assessed which were the optimal endometrial preparation protocols, few analyzed the stage and the number of embryos. This study compared the pregnancy outcomes and perinatal obstetric complications of patients who were transferred two cleavage-stage (day 2 or day 3) frozen embryos with the natural cycle and those with the hormone replacement therapy cycle.

DESIGN

This study was a secondary analysis of data from a multicentre randomized controlled trial designed to compare the pregnancy and perinatal outcomes after frozen versus fresh embryo transfer. In this study, a total of 908 patients who were transferred two cleavage-stage (day 2 or day 3) embryos in the original trial were analyzed. Pregnancy outcomes and perinatal obstetric complications after the natural cycle and the hormone replacement therapy cycle were compared.

RESULT

We found the endometrium in the natural group was significantly thicker than the hormone replacement therapy cycle group (p<0.01). The implantation rate (42.6% vs 37.3% p=0.049) showed a significant difference between the natural cycle group and the hormone replacement therapy cycle group. Compared to the natural cycle group, the hormone replacement therapy cycle group was associated with an increased risk of caesarean section (72.3% vs 84.5, p=0.009).

CONCLUSION

The natural cycle protocol yielded thicker endometria, a higher implantation rate and a lower risk of caesarean section than the hormone replacement therapy protocol in the transfer of two cleavage-stage frozen embryos. The natural cycle protocol was the better endometrial preparation protocol for frozen embryo transfer.

Vascular Endothelial Growth Factor Delivery to Placental Basal Plate Promotes Uterine Artery Remodeling in the Primate

Extravillous trophoblast (EVT) uterine artery remodeling (UAR) promotes placental blood flow, but UAR regulation is unproven. Elevating estradiol (E2) in early baboon pregnancy suppressed UAR and EVT vascular endothelial growth factor (VEGF) expression, but this did not prove that VEGF mediated this process. Therefore, our primate model of prematurely elevating E2 and contrast-enhanced ultrasound cavitation of microbubble (MB) carriers was used to deliver VEGF DNA to the placental basal plate (PBP) to establish the role of VEGF in UAR. Baboons were treated on days 25 to 59 of gestation (term, 184 days) with E2 alone or with E2 plus VEGF DNA-conjugated MBs briefly infused via a maternal peripheral vein on days 25, 35, 45, and 55. At each of these times an ultrasound beam was directed to the PBP to collapse the MBs and release VEGF DNA. VEGF DNA-labeled MBs per contrast agent was localized in the PBP but not the fetus. Remodeling of uterine arteries >25 µm in diameter on day 60 was 75% lower (P < 0.001) in E2-treated (7% ± 2%) than in untreated baboons (30% ± 4%) and was restored to normal by E2/VEGF. VEGF protein levels (signals/nuclear area) within the PBP were twofold lower (P < 0.01) in E2-treated (4.2 ± 0.9) than in untreated (9.8 ± 2.8) baboons and restored to normal by E2/VEGF (11.9 ± 1.6), substantiating VEGF transfection. Thus, VEGF gene delivery selectively to the PBP prevented the decrease in UAR elicited by prematurely elevating E2 levels, establishing the role of VEGF in regulating UAR in vivo during primate pregnancy.

Frozen versus fresh single blastocyst transfer in ovulatory women: a multicentre, randomised controlled trial

BACKGROUND

Elective single embryo transfer (eSET) has been increasingly advocated, but concerns about the lower pregnancy rate after reducing the number of embryos transferred have encouraged transfer of multiple embryos. Extended embryo culture combined with electively freezing all embryos and undertaking a deferred frozen embryo transfer might increase pregnancy rate after eSET. We aimed to establish whether elective frozen single blastocyst transfer improved singleton livebirth rate compared with fresh single blastocyst transfer.

METHODS

This multicentre, non-blinded, randomised controlled trial was undertaken in 21 academic fertility centres in China. 1650 women with regular menstrual cycles undergoing their first cycle of in-vitro fertilisation were enrolled from Aug 1, 2016, to June 3, 2017. Eligible women were randomly assigned to either fresh or frozen single blastocyst transfer. The randomisation sequence was computer generated, with block sizes of two, four, or six, stratified by study site. For those assigned to frozen blastocyst transfer, all blastocysts were cryopreserved and a delayed frozen-thawed single blastocyst transfer was done. The primary outcome was singleton livebirth rate. Analysis was by intention to treat. This trial is registered at the Chinese Clinical Trial Registry, number ChiCTR-IOR-14005405.

FINDINGS

825 women were assigned to each group and included in analyses. Frozen single blastocyst transfer resulted in higher rates of singleton livebirth than did fresh single blastocyst transfer (416 [50%] vs 329 [40%]; relative risk [RR] 1·26, 95% CI 1·14-1·41, p<0·0001). The risks of moderate or severe ovarian hyperstimulation syndrome (four of 825 [0·5%] in frozen single blastocyst transfer vs nine of 825 [1·1%] in fresh single blastocyst transfer; p=0·16), pregnancy loss (134 of 583 [23·0%] vs 124 of 481 [25·8%]; p=0·29), other obstetric complications, and neonatal morbidity were similar between the two groups. Frozen single blastocyst transfer was associated with a higher risk of pre-eclampsia (16 of 512 [3·1%] vs four of 401 [1·0%]; RR 3·13, 95% CI 1·06-9·30, p=0·029).

INTERPRETATION

Frozen single blastocyst transfer resulted in a higher singleton livebirth rate than did fresh single blastocyst transfer in ovulatory women with good prognosis. The increased risk of pre-eclampsia after frozen blastocyst transfer warrants further studies.

FUNDING

The National Key Research and Development Program of China.