Freezing of all embryos in in vitro fertilization is beneficial in high responders, but not intermediate and low responders: an analysis of 82,935 cycles from the Society for Assisted Reproductive Technology registry

High estradiol levels in fresh embryo transfer cycles are not associated with detrimental impact on birth outcomes

PURPOSE

There is an unclear relationship between estradiol levels and fresh embryo transfer (ET) outcomes. We determined the relationship between estradiol on the day of trigger, in fresh ET cycles without premature progesterone elevation, and good birth outcomes (GBO).

METHODS

We identified autologous fresh ET cycles from 2015 to 2021 at multiple clinics in the USA. Patients with recurrent pregnancy loss, uterine factor, and elevated progesterone on the day of trigger (progesterone > 2 ng/mL or 3-day area under the curve > 4.5 ng/mL) were excluded. The primary outcome was GBO (singleton, term, live birth with appropriate weight). Log-binomial generalized estimating equations determined the likelihood of outcomes.

RESULTS

Of 17,608 fresh ET cycles, 5025 (29%) yielded GBO. Cycles with estradiol ≥ 4000 pg/mL had a greater likelihood of GBO compared to cycles < 1000 pg/mL (aRR = 1.32, 95% CI 1.13-1.54). Pairwise comparisons of estradiol between < 1000 pg/mL versus 1000-1999 pg/mL and 1000-1999 pg/mL versus 2000-2999 pg/mL revealed a higher likelihood of GBO with higher estradiol (aRR 0.83, 95% CI 0.73-0.95; aRR 0.91, 95% CI 0.85-0.97, respectively). Comparisons amongst more elevated estradiol levels revealed that the likelihood of GBO remained similar between groups (2000-2999 pg/mL versus 3000-3999 pg/mL, aRR 1.04, 95% CI 0.97-1.11; 3000-3999 pg/mL versus ≥ 4000 pg/mL, aRR 0.96, 95% CI 0.9-1.04).

CONCLUSION

In fresh ET cycles, higher estradiol levels were associated with an increased prevalence of GBO until estradiol 2000-2999 pg/mL, thereafter plateauing. In fresh ET candidates, elevated estradiol levels should not preclude eligibility though premature progesterone rise, and risk of ovarian hyperstimulation syndrome must still be considered.

Effects of total gonadotropin dose on embryo quality and clinical outcomes with AMH stratification in IVF cycles: a retrospective analysis of 12,588 patients

BACKGROUND

Recent studies about the effect of gonadotropin (Gn) dose on the clinical outcomes of IVF are still controversial, and no studies have analyzed the relationship between Gn dose and embryo quality. Since AMH is a strong predictor of oocyte quality, we aim to evaluate the relationship between total Gn dose and embryo quality and clinical outcomes at different AMH levels in IVF cycles.

METHODS

A total of 12,588 patients were enrolled in the retrospective study. The included cycles were categorized by serum AMH levels (AMH ≤ 1 ng/ml, 1 ng/ml < AMH ≤ 3 ng/ml, 3 ng/ml < AMH ≤ 5 ng/ml, AMH > 5 ng/ml), total Gn dosage (< 1875 IU, 1875-3750 IU and ≥ 3750 IU) and female age (< 35 years and 35-42 years). The embryo quality and clinical outcomes were the measure outcomes.

RESULTS

The top-day3 embryos rate decreased with the increase of total Gn dose in nearly all age and AMH subgroups, but this trend was not obvious in the AMH > 5 ng/ml group and AMH ≤ 1 ng/ml group. The blastocyst formation rate and high-quality blastulation rate had a negative relationship with Gn does for women aged < 35 years in the AMH ≤ 5 ng/ml groups, except for the AMH > 5 ng/ml group (P < 0.001). However, when women were 35-42 years old, regardless of AMH levels, the blastocyst formation rate and high-quality blastulation rate decreased as Gn dose increased. Clinical outcomes (implantation rate, clinical pregnancy rate and live birth rate) decreased with the increase of Gn dose in all ages and AMH stratifications.

CONCLUSIONS

The total dose of Gn may have different effects on embryo quality at different serum AMH levels, and the negative effects of total dose of Gn on clinical outcomes may be realized by impairing both embryo quality and endometrium.

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.

Luteal phase support in assisted reproductive technology

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

Artificial intelligence-powered assisted ranking of sibling embryos to increase first cycle pregnancy rate

RESEARCH QUESTION

Could EMBRYOLY, an artificial intelligence embryo evaluation tool, assist embryologists to increase first cycle pregnancy rate and reduce cycles to pregnancy for patients?

DESIGN

Data from 11,988 embryos were collected via EMBRYOLY from 2666 egg retrievals (2019-2022) across 11 centres in France, Spain and Morocco using three time-lapse systems (TLS). Data from two independent clinics were also examined. EMBRYOLY's transformer-based model was applied to transferred embryos to evaluate ranking performances against pregnancy and birth outcomes. It was applied to cohorts to rank sibling embryos (including non-transferred) according to their likelihood of clinical pregnancy and to compute the agreement with the embryologist's highest ranked embryo. Its effect on time to pregnancy and first cycle pregnancy rate was evaluated on cohorts with multiple single blastocyst transfers, assuming the embryologist would have considered EMBRYOLY's ranking on the embryos favoured for transfer.

RESULTS

EMBRYOLY's score correlated significantly with clinical pregnancies and live births for cleavage and blastocyst transfers. This held true for clinical pregnancies from blastocyst transfers in two independent clinics. In cases of multiple single embryo transfers, embryologists achieved a 19.8% first cycle pregnancy rate, which could have been improved to 44.1% with the adjunctive use of EMBRYOLY (McNemar's test: P < 0.001). This could have reduced cycles to clinical pregnancy from 2.01 to 1.66 (Wilcoxon test: P < 0.001).

CONCLUSIONS

EMBRYOLY's potential to enhance first cycle pregnancy rates when combined with embryologists' expertise is highlighted. It reduces the number of unsuccessful cycles for patients across TLS and IVF centres.

IVF with reception of oocytes from partner in lesbian couples: a systematic review and SWOT analysis

The growing utilization of assisted reproductive technology (ART) by the LGBTQ+ community, especially among lesbian couples, challenges societal norms and promotes inclusivity. The reception of oocytes from partner (ROPA) technique enables both female partners to have a biological connection to their child. A systematic review was conducted of the literature on ROPA IVF to provide the latest data and a SWOT analysis was subsequently performed to understand the strengths, weaknesses, opportunities and threats associated with ROPA IVF. Publications from 2000 to 2023 with relevant keywords were reviewed and 16 records were included. Five studies provided clinical information on couples who used ROPA IVF. ROPA IVF provides a unique opportunity for a biological connection between the child and both female partners and addresses concerns related to oocyte donation and anonymity. Weaknesses include limited cost-effectiveness data and unresolved practical implications. Opportunities lie in involving both partners in parenthood, advancing ART success rates and mitigating risks. Threats encompass increased pregnancy complications, ethical concerns, insufficient safety data, legal or cultural barriers, and emotional stress. In conclusion, ROPA IVF offers a promising solution for lesbian couples seeking to create a family in which both partners want to establish a biological connection with their child.

Effects of different progesterone levels on reproductive outcomes in assisted reproductive technologies: from molecular basis to treatment strategies

PURPOSE

The aim of this narrative review is to offer an overview about the role of progesterone levels on pregnancy outcome in patients undergoing assisted reproductive technologies (ARTs).

METHODS

A detailed computerized search of the literature was performed in the main electronic databases (MEDLINE, EMBASE, Web of Science) to determine the importance of elevated progesterone levels at different stages of the cycle for pregnancy rates in the in vitro fertilization (IVF) cycle. Our review also provides information on the differences between elevated progesterone levels and their interpretation in normal and in poorly responding women.

RESULTS

After careful evaluation, our search strategy yielded a total of 15 included articles, showing the possible factors that may have had an impact on the increased progesterone level before human chorionic gonadotropin (HCG) injection and the different thresholds above which the pregnancy rate was lower. Furthermore, increased progesterone on cycle day 2 or 3 could serve as a marker for increased progesterone in the late follicular phase, which is associated with a lower pregnancy rate.

CONCLUSION

Despite the literature data that support the negative effect of elevated progesterone on fresh cycles, due to lack of randomized controlled trials, the value of measuring progesterone in daily practice is questionable. Available evidence supports the detrimental effect of elevated progesterone in different subgroups of women, although there is still the need for defining different thresholds and durations of high progesterone exposure. The need for various thresholds for different cohorts of women, the inter-assay variability is making this decision harder.

Good practice recommendations on add-ons in reproductive medicine†

STUDY QUESTION

Which add-ons are safe and effective to be used in ART treatment?

SUMMARY ANSWER

Forty-two recommendations were formulated on the use of add-ons in the diagnosis of fertility problems, the IVF laboratory and clinical management of IVF treatment.

WHAT IS KNOWN ALREADY

The innovative nature of ART combined with the extremely high motivation of the patients has opened the door to the wide application of what has become known as 'add-ons' in reproductive medicine. These supplementary options are available to patients in addition to standard fertility procedures, typically incurring an additional cost. A diverse array of supplementary options is made available, encompassing tests, drugs, equipment, complementary or alternative therapies, laboratory procedures, and surgical interventions. These options share the common aim of stating to enhance pregnancy or live birth rates, mitigate the risk of miscarriage, or expedite the time to achieving pregnancy.

STUDY DESIGN, SIZE, DURATION

ESHRE aimed to develop clinically relevant and evidence-based recommendations focusing on the safety and efficacy of add-ons currently used in fertility procedures in order to improve the quality of care for patients with infertility.

PARTICIPANTS/MATERIALS, SETTING, METHODS

ESHRE appointed a European multidisciplinary working group consisting of practising clinicians, embryologists, and researchers who have demonstrated leadership and expertise in the care and research of infertility. Patient representatives were included in the working group. To ensure that the guidelines are evidence-based, the literature identified from a systematic search was reviewed and critically appraised. In the absence of any clear scientific evidence, recommendations were based on the professional experience and consensus of the working group. The guidelines are thus based on the best available evidence and expert agreement. Prior to publication, the guidelines were reviewed by 46 independent international reviewers. A total of 272 comments were received and incorporated where relevant.

MAIN RESULTS AND THE ROLE OF CHANCE

The multidisciplinary working group formulated 42 recommendations in three sections; diagnosis and diagnostic tests, laboratory tests and interventions, and clinical management.

LIMITATIONS, REASONS FOR CAUTION

Of the 42 recommendations, none could be based on high-quality evidence and only four could be based on moderate-quality evidence, implicating that 95% of the recommendations are supported only by low-quality randomized controlled trials, observational data, professional experience, or consensus of the development group.

WIDER IMPLICATIONS OF THE FINDINGS

These guidelines offer valuable direction for healthcare professionals who are responsible for the care of patients undergoing ART treatment for infertility. Their purpose is to promote safe and effective ART treatment, enabling patients to make informed decisions based on realistic expectations. The guidelines aim to ensure that patients are fully informed about the various treatment options available to them and the likelihood of any additional treatment or test to improve the chance of achieving a live birth.

STUDY FUNDING/COMPETING INTEREST(S)

All costs relating to the development process were covered from ESHRE funds. There was no external funding of the development process or manuscript production. K.L. reports speakers fees from Merck and was part of a research study by Vitrolife (unpaid). T.E. reports consulting fees from Gynemed, speakers fees from Gynemed and is part of the scientific advisory board of Hamilton Thorne. N.P.P. reports grants from Merck Serono, Ferring Pharmaceutical, Theramex, Gedeon Richter, Organon, Roche, IBSA and Besins Healthcare, speakers fees from Merck Serono, Ferring Pharmaceutical, Theramex, Gedeon Richter, Organon, Roche, IBSA and Besins Healthcare. S.R.H. declares being managing director of Fertility Europe, a not-for-profit organization receiving financial support from ESHRE. I.S. is a scientific advisor for and has stock options from Alife Health, is co-founder of IVFvision LTD (unpaid) and received speakers' fee from the 2023 ART Young Leader Prestige workshop in China. A.P. reports grants from Gedeon Richter, Ferring Pharmaceuticals and Merck A/S, consulting fees from Preglem, Novo Nordisk, Ferring Pharmaceuticals, Gedeon Richter, Cryos and Merck A/S, speakers fees from Gedeon Richter, Ferring Pharmaceuticals, Merck A/S, Theramex and Organon, travel fees from Gedeon Richter. The other authors disclosed no conflicts of interest.

DISCLAIMER

This Good Practice Recommendations (GPRs) document represents the views of ESHRE, which are the result of consensus between the relevant ESHRE stakeholders and are based on the scientific evidence available at the time of preparation.ESHRE GPRs should be used for information and educational purposes. They should not be interpreted as setting a standard of care or bedeemedinclusive of all proper methods of care, or be exclusive of other methods of care reasonably directed to obtaining the same results.Theydo not replace the need for application of clinical judgement to each individual presentation, or variations based on locality and facility type.Furthermore, ESHRE GPRs do not constitute or imply the endorsement, or favouring, of any of the included technologies by ESHRE.

An appraisal of current embryo transfer strategies

Embryo transfer, one of the most essential procedures in assisted reproductive technology, plays a vital role in the success of in-vitro fertilization and intracytoplasmic sperm injection. During the last decades, the strategies for embryo transfer have changed dramatically. In this review, we evaluate the efficacy and safety of several current embryo transfer strategies including fresh versus frozen embryo transfer, cleavage- versus blastocyst-stage embryo transfer, and single- versus double-embryo transfer. Available evidence indicates that the freeze-only strategy improves the live birth rate after the first embryo transfer in high responders while making no difference in normal responders. The risk of ovarian hyperstimulation syndrome is significantly reduced in the freeze-only strategy. Fresh blastocyst-stage embryo transfer increased live birth rate compared to cleavage-stage embryo transfer. The best embryo transfer strategy is one which tailors to individual circumstances and preferences.

The utility of all-freeze IVF cycles depends on the composition of study populations

BACKGROUND

Because often introduced without proper validation studies, so-called "add-ons" to IVF have adversely affected in vitro fertilization (IVF) outcomes worldwide. All-freeze cycles (embryo banking, EB) with subsequently deferred thaw cycles are such an "add-on" and, because of greatly diverging reported outcomes, have become increasingly controversial. Based on "modeling" with selected patient populations, we in this study investigated whether reported outcome discrepancies may be the consequence of biased patient selection.

RESULTS

In four distinct retrospective case control studies, we modeled in four cohort pairings how cryopreservation with subsequent thaw cycles affects outcomes differently in good-, average- and poor-prognosis patients: (i) 127 fresh vs. 193 frozen donor-recipient cycles to model best-prognosis patients; (ii) 741 autologous fresh non-donor IVF cycles vs. 217 autologous frozen non-donor IVF cycles to model average prognosis patients; (iii) 143 favorably selected autologous non-donor IVF cycles vs. the same 217 frozen autologous cycles non-donor to monitor good- vs. average-prognosis patients; and (iv) 598 average and poor-prognosis autologous non-donor cycles vs. the same 217 frozen autologous non-donor cycles to model poor vs. average prognosis patients. In best-prognosis patients, EB marginally improved IVF outcomes. In unselected patients, EB had no effects. In poor-prognosis patients, EB adversely affected IVF outcomes. Unexpectedly, the study also discovered independent-of-age-associated chromosomal abnormalities, a previously unreported effect of recipient age on miscarriage risk in donor-egg recipients.

CONCLUSIONS

In poor-prognosis patients, EB cycles should be considered contraindicated. In intermediate-prognosis patients EB does not appear to change outcomes, not warranting additional cost and time delays. Therefore, only good-prognosis patients are candidates for EB, though they will experience only marginal benefits that may not be cost-effective.

Number of oocytes and IVF outcomes: Real-world evidence

Randomized controlled trials (RCTs) are gold standard to study the effect of an intervention and establish causation between the treatment and outcomes. However, RCTs have the disadvantage of being expensive, entailing high resource investments and involving only selected patient populations under experimental settings. Real-world evidence (RWE) from real-world data (RWD) involves a heterogenous patient population in real-world settings. RWE is less expensive and quicker than RCTs; it can provide complimentary evidence if methodological challenges, such as residual confounding and susceptibility to bias, are considered when interpreting the findings. This review examines RWE regarding the association between the number of oocytes following ovarian stimulation and IVF outcomes into shaping current IVF practices.

Reconsideration of the safety and effectiveness of human oocyte cryopreservation

Mature oocyte cryopreservation (OC) has become increasingly common since the American Society for Reproductive Medicine declared OC to no longer be experimental. Utilization of the open vitrification protocol has led to a marked improvement in the efficacy of oocyte cryopreservation. However, the safety and effectiveness of this cryopreservation method remain controversial. A previous report stated that among all initiated recipient cycles, the live-birth rate among recipients of all ages was significantly higher when using fresh donor oocytes (FDOs) rather than cryopreserved donor oocytes (CDOs). Confounding patient characteristics were noted as possible causes. OC stands as an acceptable elective medical intervention for preserving fertility in women. To further understand the effects of OC on the live birth rate resulting from fresh versus cryopreserved donor oocytes, reported data from the Society for Assisted Reproductive Technology from 2013 to 2020 were analyzed. The mean of the mean live-birth rate in all ages resulting from FDOs was 49.0% (44.6-53.3%) versus 41.0% (39.1-43.2%) for CDOs (difference, 8.0% [95% confidence interval, 5.35-10.57%], p value < 0.001). The lower live-birth rate observed for CDOs versus FDOs has been consistent throughout past decades. While there has been no reported increase in the aneuploidy rate for CDOs compared to FDOs, differences in the nondisjunction separation rate among different chromosomes were described in a recent report. Open vitrification culture medium usually contains high concentrations of cryoprotectants, such as 15% dimethyl sulfoxide (DMSO) and 15% ethylene glycol (EG). Recent studies showed that tissue culture with 0.1% DMSO or 10% EG resulted in deregulation of gene expression, disruption of epigenetic imprints, and accumulation of reactive oxygen species. The addition of melatonin, which can remove reactive oxygen species from vitrification medium, was shown to improve CDOs qualities and functions to conditions similar to those of FDOs; however, there were insufficient data to conclude that melatonin could improve the lower live-birth rate. These factors that affect live birth rates, birth defects, birth weights and developmental health cannot be ignored and perhaps need to be studied again and followed when evaluating the true effectiveness of human oocyte cryopreservation.

The impact of the embryo banking on the cumulative live birth rate in women with poor ovarian response according to the Bologna criteria

Purpose

To evaluate the impact of embryo banking on the cumulative live birth rate (CLBR) and the time to live birth (TTLB) in poor ovarian responders (POR) according to the Bologna criteria.

Methods

A total of 276 infertile women undergoing IVF with POR were included in this retrospective study. They were divided into two groups with (n = 121) or without (n = 155) embryo banking at the discretion of the attending physicians. A total of 656 and 405 stimulation cycles were started in the two groups respectively during the 24 month follow-up.

Results

The biochemical pregnancy, clinical pregnancy, ongoing pregnancy, and live birth rate per transfer were comparable between two groups (p > 0.05). The CLBR was significantly lower in the banking group than in the non-banking group (31.4% (38/121) and 43.2% (67/151), p < 0.05). TTLB was significantly longer in the banking group (20.5 months vs. 16.0 months, p < 0.001). In the Kaplan-Meier analysis, the cumulative incidence of live birth was significantly lower in the banking group compared with the non-banking group (Log rank test, chi-square = 21.958, p < 0.001).

Conclusions

Embryo banking in women undergoing IVF with POR based on the Bologna criteria reduces CLBR and lengthens TTLB when compared with no embryo banking.

Freeze-all policy versus luteal phase support with low dose of human chorionic gonadotrophin for high-responder patients undergoing intracytoplasmic sperm injection on pregnancy outcomes: a retrospective cohort observational study

Background

The literature has always controversies on the use of freeze-all policy in high-responder women performing intracytoplasmic sperm injection. In this article, we discuss the benefits of freeze-all policy on the incidence of pregnancy outcomes and the complications.

The main body of abstract

Freeze-all policy is applied to the intracytoplasmic sperm injection program by freezing of all embryos and delaying embryo transfer to another subsequent ovarian cycle, to decrease the incidence of ovarian hyperstimulation syndrome, especially in high-responder women. Unfortunately, freeze-all policy is correlated with an increase in the economic costs and more ICSI laboratory effort. Delayed embryo transfer (ET) is correlated with more anxiety among the patients. An alternative strategy is to perform fresh embryo transfer with more intensive luteal phase support to compensate for the negative effect of the GnRH agonist on the endometrial receptivity and luteal phase support.

Short conclusion

The freeze-all policy had better pregnancy rates with less incidence of moderate to severe hyperstimulation syndrome compared with original fresh embryo transfer in high-responder women performing intracytoplasmic sperm injection.

Anti-Müllerian hormone in guiding the selection of a freeze-all versus a fresh embryo transfer strategy: a cohort study

PURPOSE

To explore an interaction effect between serum anti-Müllerian hormone (AMH) levels and the relative treatment effect of a freeze-all versus a fresh embryo transfer strategy on live birth.

METHODS

This was a retrospective cohort study investigating couples with infertility and eligible for both freeze-all and fresh embryo transfer between 2017 and 2019. Women with an absolute indication for a freeze-all strategy were excluded. Multivariable fractional polynomial interaction analysis within a logistic regression model was used to evaluate whether the treatment effect of a freeze-all versus a fresh transfer strategy varied at different AMH levels. Non-linear interactions were also considered. The primary outcome was the live birth after the first transfer.

RESULTS

A total of 13,503 women underwent a fresh embryo transfer and 2247 women underwent a freeze-all strategy. Live birth rates were slightly higher in the freeze-all group compared to those in the fresh embryo transfer group (35% vs 33%). There was a non-linear interaction between baseline serum AMH levels and the relative treatment effect of a freeze-all strategy versus a fresh transfer strategy on live birth (P = 0.0161). The benefit on live birth from a freeze-all embryo transfer strategy was greatest in women with a high serum level (> 7 ng/ml). The interaction remained valid when different imputation methods were used.

CONCLUSION

As serum AMH level increased, there was a nonlinear increase in relative treatment effect of a freeze-only transfer versus a fresh transfer strategy on live birth, and such an effect reaches its maximum in women with high AMH levels.

Impact of increasing antimüllerian hormone level on in vitro fertilization fresh transfer and live birth rate

Objective

The objective of our study was to assess the association between AMH and live birth among women with elevated AMH undergoing first fresh IVF. Serum antimüllerian hormone (AMH) correlates with oocyte yield during in vitro fertilization (IVF). However, there are limited data regarding IVF outcomes in women with elevated AMH levels.

Design

Retrospective cohort study using the Society for Assisted Reproductive Technology Clinical Outcomes Reporting System database from 2012-2014.

Setting

Fertility clinics reporting to Society for Assisted Reproductive Technology.

Patients

First, fresh, autologous IVF cycles with elevated AMH levels (≥5.0 ng/mL). Subanalyses were performed to examine patients with or without polycystic ovary syndrome (PCOS).

Interventions

None.

Main Outcome Measures

Odds of live birth.

Results

Our cohort included 10,615 patients with elevated an AMH level, including 2,707 patients with PCOS only. The adjusted odds of live birth per initiated cycle were significantly lower per each unit increase in the AMH level (odds ratio, 0.97; 95% confidence interval, 0.96-0.98). Increasing AMH level was associated with increased cancellation of fresh transfer (odds ratio, 1.12; 95% confidence interval, 1.10-1.15) up to an AMH level of 12 ng/mL. The decrease in the live birth rate appears to be caused by the increasing incidence of cancellation of fresh transfer because the live birth rate per completed transfer was maintained. Similar trends were observed in the PCOS and non-PCOS subanalyses.

Conclusions

Among patients with AMH levels of ≥5 ng/mL undergoing fresh, autologous IVF, each unit increase in AMH level is associated with a 3% decrease in odds of live birth because of the increased incidence of fresh embryo transfer cancellation.

Endometrial thickness is an independent risk factor of hypertensive disorders of pregnancy: a retrospective study of 13,458 patients in frozen-thawed embryo transfers

BACKGROUND

Hypertensive disorders of pregnancy (HDP) are an important cause of maternal and fetal mortality, and its potential risk factors are still being explored. Endometrial thickness (EMT), as one of the important monitoring indicators of endometrial receptivity, has been confirmed to be related to the incidence of HDP in fresh embryo transfer. Our study was designed to investigate whether endometrial thickness is associated with the risk of hypertensive disorders of pregnancy in frozen-thawed embryo transfer (FET).

METHODS

This respective cohort study enrolled 13,458 women who received vitrified embryo transfer and had a singleton delivery in the Reproductive Hospital affiliated to Shandong University from January 2015 to December 2019. We set strict screening criteria and obtained the information from the hospital electronic medical system. Statistical methods including logistic regression analysis, receiver operating characteristic curve and restricted cubic spline were used to evaluate the relationship between endometrial thickness and the incidence of pregnancy-induced hypertension.

RESULTS

The incidences of HDP in a thin endometrial thickness group (< 0.8 cm) and a thick endometrial thickness group (> 1.2 cm) were significantly greater than in a reference group (0.8 cm-1.2 cm) (7.98 and 5.24% vs 4.59%, P <  0.001). A nonlinear relationship between endometrial thickness and risk of hypertensive disorders of pregnancy was examined by restricted cubic spline (P <  0.001). The thin endometrial thickness and thick endometrial thickness groups were significantly associated with the risk of HDP after adjusting for confounding variables by stepwise logistic regression analysis. Subsequently, subgroup logistic regression analysis based on endometrial preparation regimens showed that thin endometria were still significantly associated with a higher morbidity rate in the artificial cycle group, while in the natural cycle group, thick endometria were closely associated with increased morbidity.

CONCLUSION

Our study manifested that both the thin and thick endometria were associated with an increased risk of hypertensive disorders of pregnancy in frozen embryo transfer cycles. Reproductive clinicians should focus on adjusting endometrial thickness in different preparation regimens; and obstetricians should be mindful of the risk of hypertension during pregnancy, when women with thin (< 0.8 cm) or excessively thicker (> 1.2 cm) endometrial thickness achieve pregnancy through frozen-thawed embryo transfer.

Lipid metabolism and endometrial receptivity

BACKGROUND

Obesity has now been recognized as a high-risk factor for reproductive health. Although remarkable advancements have been made in ART, a considerable number of infertile obese women still suffer from serial implantation failure, despite the high quality of embryos transferred. Although obesity has long been known to exert various deleterious effects on female fertility, the underlying mechanisms, especially the roles of lipid metabolism in endometrial receptivity, remain largely elusive.

OBJECTIVE AND RATIONALE

This review summarizes current evidence on the impacts of several major lipids and lipid-derived mediators on the embryonic implantation process. Emerging methods for evaluating endometrial receptivity, for example transcriptomic and lipidomic analysis, are also discussed.

SEARCH METHODS

The PubMed and Embase databases were searched using the following keywords: (lipid or fatty acid or prostaglandin or phospholipid or sphingolipid or endocannabinoid or lysophosphatidic acid or cholesterol or progesterone or estrogen or transcriptomic or lipidomic or obesity or dyslipidemia or polycystic ovary syndrome) AND (endometrial receptivity or uterine receptivity or embryo implantation or assisted reproductive technology or in vitro fertilization or embryo transfer). A comprehensive literature search was performed on the roles of lipid-related metabolic pathways in embryo implantation published between January 1970 and March 2022. Only studies with original data and reviews published in English were included in this review. Additional information was obtained from references cited in the articles resulting from the literature search.

OUTCOMES

Recent studies have shown that a fatty acids-related pro-inflammatory response in the embryo-endometrium boundary facilitates pregnancy via mediation of prostaglandin signaling. Phospholipid-derived mediators, for example endocannabinoids, lysophosphatidic acid and sphingosine-1-phosphate, are associated with endometrial receptivity, embryo spacing and decidualization based on evidence from both animal and human studies. Progesterone and estrogen are two cholesterol-derived steroid hormones that synergistically mediate the structural and functional alterations in the uterus ready for blastocyst implantation. Variations in serum cholesterol profiles throughout the menstrual cycle imply a demand for steroidogenesis at the time of window of implantation (WOI). Since 2002, endometrial transcriptomic analysis has been serving as a diagnostic tool for WOI dating. Numerous genes that govern lipid homeostasis have been identified and, based on specific alterations of lipidomic signatures differentially expressed in WOI, lipidomic analysis of endometrial fluid provides a possibility for non-invasive diagnosis of lipids alterations during the WOI.

WIDER IMPLICATIONS

Given that lipid metabolic dysregulation potentially plays a role in infertility, a better understanding of lipid metabolism could have significant clinical implications for the diagnosis and treatment of female reproductive disorders.

Ovarian Stimulation in Assisted Reproductive Technology Cycles for Varied Patient Profiles: An Indian Perspective

Controlled ovarian stimulation has been an integral part of in vitro fertilisation (IVF) treatment cycles. Availability of different gonadotropins for ovarian stimulation and gonadotropin releasing hormone (GnRH) analogues for prevention of premature rise of leutinising hormone during follicular phase offer an opportunity to utilise them for a successful outcome in women with different subsets of ovarian response. Further, use of GnRH agonist as an alternative for human chorionic gonadotropin improves safety of ovarian stimulation in hyper-responders. Mild ovarian stimulation protocols have emerged as an alternative to conventional protocols in the recent years. Individualisation plays an important role in improving safety of IVF in hyper-responders while efforts continue to improve efficacy in poor responders. Some of the follicular and peri-ovulatory phase interventions may be associated with negative impact on the luteal phase and segmentalisation of the treatment with frozen embryo transfer may be an effective strategy in such a clinical scenario. This narrative review looks at the available evidence on various aspects of ovarian stimulation strategies and their consequences. In addition, it provides a concise summary of the evidence that has emerged from India on various aspects of ovarian stimulation.

Is a freeze-all strategy necessary for all embryo transfers : Fresh embryo transfer without progesterone elevation results in an equivalent pregnancy rate to cryopreserved embryo transfer

Objectives : It has been suggested that the clinical outcomes of frozen-thawed embryo transfer (ET) are superior to those of fresh embryo transfer. We examined whether a freeze-all strategy is necessary for all embryo transfers, and, if not, to evaluate the conditions in which the pregnancy rates of fresh embryo transfer and frozen-thawed ET did not differ. Methods : Patients who underwent blastocyst transfer at Tokushima University Hospital between 2008 and 2019 were enrolled. The clinical outcomes and clinical characteristics of 1,022 patients that underwent fresh embryo transfer and 1,728 patients that underwent frozen-thawed ET were examined retrospectively. We considered the factors that influenced the pregnancy outcomes of fresh embryo transfer. Results : The frozen-thawed ET group exhibited significantly higher pregnancy, live-birth, and miscarriage rates than the fresh embryo transfer group. In the fresh embryo transfer group, a high progesterone level on the day of the human chorionic gonadotropin (hCG) trigger and lower grade embryos were risk factors for a low pregnancy rate. However, in the cases in which the progesterone level was < 1.0 ng / mL the pregnancy rate was equal to that of frozen-thawed ET. Conclusions : A freeze-all strategy is not necessary for embryo transfers, but should be employed in cases involving pre-ovulatory progesterone elevation. J. Med. Invest. 69 : 224-229, August, 2022.

Early Spontaneous Abortion in Fresh- and Frozen-Embryo Transfers: An Analysis of Over 35,000 Transfer Cycles

BACKGROUND

The aim of this study was to explore the risk factors for early spontaneous abortion (ESA) in fresh- and frozen-embryo transfers.

METHODS

This retrospective cohort study comprised a total of 35,076 patients, including 15,557 women in the fresh-embryo transfer group and 19,519 women in the frozen-embryo transfer group from January 2016 to December 2020. The primary outcome of this study was ESA, which we defined as the termination of embryonic development before 12 weeks of pregnancy (i.e., an early abortion after artificial multi-fetal pregnancy reduction was excluded).

RESULTS

In the 35,076 ART transfer cycles, the incidence of ESA was 5.77% (2023/35,076), and the incidence rates for ESA in fresh and frozen cycles were 4.93% (767 of 15,557) and 6.43% (1,256 of 19,519), respectively. Using a multivariate logistic regression analysis model, maternal age, body mass index (BMI), and number of embryos transferred were independent predictors for ESA. In addition, frozen-thawed transfer was a risk factor for ESA as compared with fresh transfer (OR = 1.207; 95% CI, 1.094-1.331; P = 0.000), blastocyst transfer was risk factor for ESA as compared with cleavage transfer (OR =1.373; 95% CI, 1.186-1.591; P = 0.000 in the total group; OR = 1.291; 95% CI, 1.111-1.499; P = 0.001 in the frozen-transfer group), and unexplained infertility was a protective factor for ESA only in the frozen group (OR = 0.746; 95% CI, 0.565-0.984; P = 0.038).

CONCLUSIONS

Maternal age, BMI, number of embryos transferred, and frozen-thawed transfer were independent risk factors for ESA in assisted reproductive technology treatment cycles.

Obesity and oocyte quality: Significant implications for ART and Emerging mechanistic insights

The prevalence of obesity in adults worldwide, and specifically in women of reproductive age, is concerning given the risks to fertility posed by the increased risk of type 2 diabetes, metabolic syndrome and other non-communicable diseases. Obesity has a multi-systemic impact in female physiology that is characterized by the presence of oxidative stress, lipotoxicity, and the activation of pro-inflammatory pathways, inducing tissue-specific insulin resistance and ultimately conducive to abnormal ovarian function. A higher body mass is linked to Polycystic Ovary Syndrome, dysregulated menstrual cycles, anovulation, and longer time to pregnancy, even in ovulatory women. In the context of ART, compared to women of normal BMI, obese women have worse outcomes in every step of their journey, resulting in reduced success measured as live birth rate. Even after pregnancy is achieved, obese women have a higher chance of miscarriage, gestational diabetes, pregnancy complications, birth defects, and most worryingly, a higher risk of stillbirth and neonatal death. The potential for compounding effects of ART on pregnancy complications and infant morbidities in obese women has not been studied. There is still much debate in the field on whether these poorer outcomes are mainly driven by defects in oocyte quality, abnormal embryo development or an unaccommodating uterine environment, however the clinical evidence to date suggests a combination of all three are responsible. Animal models of maternal obesity shed light on the mechanisms underlaying the effects of obesity on the peri-conception environment, with recent findings pointing to lipotoxicity in the ovarian environment as a key driver of defects in oocytes that have not only reduced developmental competence but long-lasting effects in offspring health.

Dual trigger protocol is an effective in vitro fertilization strategy in both normal and high responders without compromising pregnancy outcomes in fresh cycles

Objective

To study the birth rates of normal vs. high responders after dual trigger of final oocyte maturation with gonadotropin-releasing hormone (GnRH) agonist and human chorionic gonadotropin in fresh in vitro fertilization (IVF) cycles in which ovarian stimulation was achieved by a flexible GnRH antagonist protocol.

Design

Retrospective cohort study.

Setting

University hospital.

Patient(s)

In women <35 years of age, 290 fresh IVF cycles using the dual trigger protocol with day 5 embryo transfers from January 2013 to July 2018 were included. Cycles excluded were those with preimplantation genetic testing, gestational carriers, donor oocytes, and fertility preservation.

Intervention(s)

IVF with dual trigger.

Main Outcome Measure(s)

Clinical pregnancy rate, live birth rate.

Result(s)

Comparing normal responders, defined as <30 oocytes retrieved, and high responders, defined as ≥30 oocytes retrieved, the clinical pregnancy rates (67.0% vs. 69.3%, respectively) and live birth rates (60.5% vs. 60.0%, respectively) were not significantly different. No cases of ovarian hyperstimulation syndrome were reported in either group.

Conclusion(s)

Ovarian stimulation by a flexible GnRH antagonist protocol followed by dual trigger yields comparable outcomes between normal and high responders in fresh IVF cycles.

Pregnancy potential and perinatal outcomes of embryos cryopreserved twice: a case-control study

RESEARCH QUESTION

What are the pregnancy and perinatal outcomes of twice-cryopreserved embryos compared with embryos cryopreserved once?

DESIGN

Retrospective register-based case-control study. The case group consisted of transfers of twice-cryopreserved embryos (n = 89), and the control group of transfers of embryos cryopreserved once (n = 304). Matching criteria were embryonic age at transfer and female age category of less than 35 years or 35 and greater.

RESULTS

The survival rate of twice-cryopreserved embryos was 92.2%, and 93.7% of the planned frozen embryo transfers (FET) could be completed. FET was performed with cleavage-stage embryos in 17 cases and 68 controls and with blastocysts in 72 cases and 238 controls. The rates of live birth (27.0% versus 31.9%, adjusted odds ratio [OR] 0.70, 95% CI 0.40-1.22, P = 0.21), clinical pregnancy (31.5% versus 36.8%, adjusted OR 0.71, 95% CI 0.42-1.21, P = 0.21) and miscarriage (4.5% versus 3.9%, adjusted OR 1.10, 95% CI 0.33-3.60, P = 0.88) in the case and the control groups were comparable. No difference was seen in the preterm delivery rate (cases 4.2% versus controls 10.3%, P = 0.69). Twenty-five children were born in the case group and 100 in the control group. No difference in birthweight was detected between the groups and there were no large for gestational age fetuses or congenital malformations in the case group.

CONCLUSIONS

Uncompromised live birth rates and neonatal outcomes may be expected after the transfer of twice-cryopreserved embryos. To avoid embryo wastage and transfer of multiple embryos, good quality surplus embryos from FET cycles may be cryopreserved again by vitrification.

The effect of late-follicular phase progesterone elevation on embryo ploidy and cumulative live birth rates

RESEARCH QUESTION

Does late-follicular phase progesterone elevation have a deleterious effect on embryo euploidy, blastocyst formation rate and cumulative live birth rates (CLBR)?

DESIGN

A multicentre retrospective cross-sectional study including infertile patients aged 18-40 years who underwent ovarian stimulation in a gonadotrophin-releasing hormone antagonist protocol and preimplantation genetic testing for aneuploidies (PGT-A) followed by a freeze-all strategy and euploid embryo transfer between August 2017 and December 2019. The sample was stratified according to the progesterone concentrations on the day of trigger: normal (≤1.50 ng/ml) and high (>1.50 ng/ml). Moreover, sensitivity analyses were performed to determine whether different conclusions would have been drawn if different cut-offs had been adopted. The primary outcome was the embryo euploidy rate. Secondary outcomes were the blastocyst formation rate, the number of euploid blastocysts and CLBR.

RESULTS

Overall 1495 intracytoplasmic sperm injection PGT-A cycles were analysed. Late-follicular phase progesterone elevation was associated with significantly higher late-follicular oestradiol concentrations (2847.56 ± 1091.10 versus 2240.94 ± 996.37 pg/ml, P < 0.001) and significantly more oocytes retrieved (17.67 ± 8.86 versus 12.70 ± 7.00, P < 0.001). The number of euploid embryos was significantly higher in the progesterone elevation group (2.32 ± 1.74 versus 1.86 ± 1.42, P = 0.001), whereas the blastocyst formation rate (47.1% [43.7-50.5%] versus 51.0% [49.7-52.4%]), the embryo euploidy rate (48.3% [44.9-51.7%] versus 49.1% [47.7-50.6%], the live birth rate in the first frozen embryo transfer (34.1% versus 31.1%, P = 0.427) and CLBR (38.9% versus 37.0%, P = 0.637) were not significantly different between the two groups.

CONCLUSIONS

Euploidy rate and CLBR do not significantly differ among PGT-A cycles with and without late-follicular progesterone elevation in a freeze-all approach.

When Should We Freeze Embryos? Current Data for Fresh and Frozen Embryo Replacement IVF Cycles

Recent years have seen a dramatic rise in the number of frozen-thawed embryo replacement (FER) cycles. Along with the advances in embryo cryopreservation techniques, the optimization of endometrial receptivity has resulted in outcomes for FER that are similar to fresh embryo transfer. However, the question of whether the Freeze all strategy is for all is nowadays a hot topic. This review addresses this issue and describes current evidence based on randomized controlled trials and observational studies. To date, it is reasonable to perform FER in cases with a clear indication for the benefits of such strategy including impending ovarian hyperstimulation syndrome (OHSS) or preimplantation genetic testing for aneuploidy (PGT-A); however, this strategy does not fit for all. This review analyses the pros and cons of the freeze all strategy highlighting the need to follow a personalized plan in embryo transfer, avoiding a freeze all methodology for all patients in an unselected manner.

The use of propensity score matching to assess the benefit of the endometrial receptivity analysis in frozen embryo transfers

OBJECTIVE

To study the impact of the endometrial receptivity analysis (ERA) on live birth rates in frozen embryo transfer (FET) cycles.

DESIGN

Retrospective cohort study.

SETTING

A single, large, university-affiliated infertility practice.

PATIENT(S)

Autologous FET cycles between January 1, 2014, and June 30, 2019, were reviewed. Multiple covariates that impact outcomes were used for propensity score matching; 133 ERA patients were matched to 353 non-ERA patients. Patients were assigned to the ERA group if they had an ERA during treatment and underwent at least one "personalized" FET based on the ERA recommendations.

INTERVENTION(S)

No interventions administered.

MAIN OUTCOME MEASURE(S)

Live birth rates per cycle in the FET cycle after ERA compared with that of matched non-ERA patients.

RESULT(S)

The live birth rates for the ERA group, 49.62%, and the matched non-ERA group, 54.96%, (odds ratio 0.8074; 95% confidence interval, 0.5424-1.2018) were not significantly different, nor was a difference seen in subanalyses based on prior number of FETs or receptivity status.

CONCLUSION(S)

The ERA identifies a patient's putative window of implantation with the goal of improving synchrony with the embryo, thereby achieving higher live birth rates. This study used propensity score matching to control for multiple covariates in a heterogenous group of patients to compare live birth rates. There was no difference in the live birth rate in patients who underwent the ERA compared with that of those who did not.

Should we still offer elective freezing of all embryos in all IVF cycles?

Elective 'freeze all', also called 'freeze only', refers to an IVF cycle where all embryos are frozen for later embryo transfer in a non-stimulated cycle, with the promise of increased success rates and prevention of ovarian hyperstimulation syndrome (OHSS) in most patients. However, 'freeze all' is associated with significantly higher perinatal complications including eclampsia, preeclampsia, chronic hypertension and large-for-gestational-age infants, without the demonstrated advantages of providing better results, except for a decrease in the incidence of OHSS, which should matter to women with polycystic ovary syndrome (PCOS) and high responders to ovarian stimulation but not to all patients. 'Freeze all' is also suggested for all simulated IVF cycles, due to the alleged 'faulty endometrium' caused by ovarian stimulation. However, there is no direct evidence that asynchronous endometrium exists, and only if preovulatory progesterone level increase, can 'freeze all' confer an advantage. We conclude that an alleged diagnosis of 'faulty endometrium' should not be used as an indication for 'freeze all'. To offset the risk of OHSS more simply, less costly and less risky solutions such as mild ovarian stimulation, to dampen the number of oocytes and to aim for transfer of a single blastocyst, should be the preferred solution to treat women with PCOS and high responders for oocyte retrieval.

Luteal Support with very Low Daily Dose of Human Chorionic Gonadotropin after Fresh Embryo Transfer as an Alternative to Cycle Segmentation for High Responders Patients Undergoing Gonadotropin-Releasing Hormone Agonist-Triggered IVF

The segmentation of the in vitro fertilization (IVF) cycle, consisting of the freezing of all embryos and the postponement of embryo transfer (ET), has become popular in recent years, with the main purpose of preventing ovarian hyperstimulation syndrome (OHSS) in patients with high response to controlled ovarian stimulation (COS). Indeed cycle segmentation (CS), especially when coupled to a GnRH-agonist trigger, was shown to reduce the incidence of OHSS in high-risk patients. However, CS increases the economic costs and the work amount for IVF laboratories. An alternative strategy is to perform a fresh ET in association with intensive luteal phase pharmacological support, able to overcome the negative effects of the GnRH-agonist trigger on the luteal phase and on endometrial receptivity. In order to compare these two strategies, we performed a retrospective, real-life cohort study including 240 non-polycystic ovarian syndrome (PCO) women with expected high responsiveness to COS (AMH >2.5 ng/mL), who received either fresh ET plus 100 IU daily human chorionic gonadotropin (hCG) as luteal support (FRESH group, n = 133), or cycle segmentation with freezing of all embryos and postponed ET (CS group, n = 107). The primary outcomes were: implantation rate (IR), live birth rate (LBR) after the first ET, and incidence of OHSS. Overall, significantly higher IR and LBR were observed in the CS group than in the FRESH group (42.9% vs. 27.8%, p < 0.05 and 32.7% vs. 19.5%, p < 0.05, respectively); the superiority of CS strategy was particularly evident when 16-19 oocytes were retrieved (LBR 42.2% vs. 9.5%, p = 0.01). Mild OHSS appeared with the same incidence in the two groups, whereas moderate and severe OHSS forms were observed only in the FRESH group (1.5% and 0.8%, respectively). In conclusion, in non-PCO women, high responders submitted to COS with the GnRH-antagonist protocol and GnRH-agonist trigger, CS strategy was associated with higher IR and LBR than the strategy including fresh ET followed by luteal phase support with a low daily hCG dose. CS appears to be advisable, especially when >15 oocytes are retrieved.

The clinical outcomes of fresh versus frozen embryos transfer in women ≥40 years with poor ovarian response

Objective

To compare the clinical outcomes of fresh embryo transfers (ETs) and frozen-thawed embryo transfers (FETs) after a freeze-all cycle in women ≥40 years old with poor ovarian response (POR).

Methods

We performed a single-center, retrospective, case-control study of patients who underwent in vitro fertilization between January 2014 and June 2019. We included a total of 192 patients aged 40 years or older from whom 3 or fewer oocytes had been retrieved and who were receiving cleavage-stage ET in this study. Of these patients, 101 and 91 patients underwent fresh ET and FET, respectively. The primary outcome was the live birth rate (LBR) after the first ET. Logistic regression analysis was used to compare the IVF outcomes and neonatal characteristics between the fresh ET and FET groups, adjusting for maternal age, body mass index, luteinizing hormone, and the number of good quality embryos transferred.

Results

The mean maternal ages and number of oocytes retrieved (43.2 years and 2.3 in both groups, P=0.902 and P=0.927, respectively) were similar in the fresh ET and FET groups. No significant difference was observed between the LBRs of the fresh ET and FET groups (adjusted odds ratio, 1.28; 95% confidence interval, 0.29–5.70). The clinical pregnancy and miscarriage rates, and neonatal characteristics (birth weights and premature infant rates) were similar between the 2 groups.

Conclusions

FET after the freeze-all strategy had no beneficial impact on the clinical outcomes of women ≥40 years with POR.

Infertility management in women with polycystic ovary syndrome: a review

Polycystic ovary syndrome is the most common endocrine disorder in women and a major cause of anovulatory infertility. Various medical options are used, alone or in combination, to treat subfertility associated with polycystic ovary syndrome. This narrative review was conducted to provide an update and summarize the available evidence on the management of polycystic ovary syndrome related infertility. A wide literature search was performed and preferably randomized controlled trials and systematic reviews were included. Management is often centered on lifestyle changes. Pharmacological ovulation induction is the next step, with recommended use of letrozole, clomiphene citrate or gonadotropins. When it fails, assisted reproductive technologies or laparoscopic ovarian drilling are frequently advised. Combination treatment with metformin is often recommended. More recent alternative and adjunctive treatments have been suggested, like inositol, vitamin D, bariatric surgery and acupuncture, but further research is needed for recommendation.

Association of Fresh Embryo Transfers Compared With Cryopreserved-Thawed Embryo Transfers With Live Birth Rate Among Women Undergoing Assisted Reproduction Using Freshly Retrieved Donor Oocytes

IMPORTANCE

In in vitro fertilization cycles using autologous oocytes, data have demonstrated higher live birth rates following cryopreserved-thawed embryo transfers compared with fresh embryo transfers. It remains unknown if this association exists in cycles using freshly retrieved donor oocytes.

OBJECTIVE

To test the hypothesis that in freshly retrieved donor oocyte cycles, a fresh embryo transfer is more likely to result in a live birth compared with a cryopreserved-thawed embryo transfer.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study using national data collected from the Society for Assisted Reproductive Technology for 33 863 recipients undergoing fresh donor oocyte cycles in the US between January 1, 2014 and December 31, 2017.

EXPOSURES

Fresh embryo transfer and cryopreserved-thawed embryo transfer.

MAIN OUTCOMES AND MEASURES

The primary outcome was live birth rate; secondary outcomes were clinical pregnancy rate and miscarriage rate. Analyses were adjusted for donor age, day of embryo transfer, use of a gestational carrier, and assisted hatching.

RESULTS

Recipients of fresh and cryopreserved-thawed embryos had comparable median age (42.0 [interquartile range {IQR}, 37.0-44.0] years vs 42.0 [IQR, 36.0-45.0] years), gravidity (1 [IQR, 0-2] vs 1 [IQR, 0-3]), parity (0 [IQR, 0-1] vs 1 [IQR, 0-1]), and body mass index (24.5 [IQR, 21.9-28.7] vs 24.4 [IQR, 21.6-28.7]). Of a total of 33 863 recipients who underwent 51 942 fresh donor oocyte cycles, there were 15 308 (29.5%) fresh embryo transfer cycles and 36 634 (70.5%) cryopreserved-thawed embryo transfer cycles. Blastocysts were transferred in 92.4% of fresh embryo transfer cycles and 96.5% of cryopreserved-thawed embryo transfer cycles, with no significant difference in the mean number of embryos transferred. Live birth rate following fresh embryo transfer vs cryopreserved-thawed embryo transfer was 56.6% vs 44.0% (absolute difference, 12.6% [95% CI, 11.7%-13.5%]; adjusted relative risk [aRR], 1.42 [95% CI, 1.39-1.46]). Clinical pregnancy rates were 66.7% vs 54.2%, respectively (absolute difference, 12.5% [95% CI, 11.6%-13.4%]; aRR, 1.34; [95% CI, 1.31-1.37]). Miscarriage rates were 9.3% vs 9.4%, respectively (absolute difference, 0.2% [95% CI, -0.4% to 0.7%]); aRR, 0.98 [95% CI, 0.91-1.07]).

CONCLUSIONS AND RELEVANCE

In this retrospective cohort study of women undergoing assisted reproduction using freshly retrieved donor oocytes, the use of fresh embryo transfers compared with cryopreserved-thawed embryo transfers was associated with a higher live birth rate. However, interpretation of the findings is limited by the potential for selection and confounding bias.

A validated prediction score for having two or more embryos for cryopreservation following freeze-all IVF cycles: an analysis utilizing SART CORS database

PURPOSE

To develop and validate a prediction score for having 2 or more embryos cryopreserved following an IVF cycle without a fresh transfer such that an embryo selection method may be applicable. We also developed a counseling tool on the probability of not having any embryos following an IVF cycle without a fresh transfer.

METHODS

We split the data into a development set and a validation set by region within the USA using a coin flip approach and subsequently performed a logistic regression model to identify factors most predictive of cryopreservation of 2 or more embryos in the development set. This model was validated in the validation set. Subsequently, a clinical prediction score was derived using the model coefficients and the predictive accuracy measured with the concordance (c) statistic.

RESULTS

A total of 31,537 potential freeze-all cycles were reported to the Society for Assisted Reproductive Technology in 2014. Of these, 57.87% produced and cryopreserved two or more embryos. We identified that age, AMH, and the number of eggs retrieved were the most significant predictors of having 2 or more embryos cryopreserved with a validated c-statistic of 0.84 (95% CI: 0.83 to 0.85). A clinical prediction score was derived from the model. 28.9% of freeze-all cycles had no embryos created from the IVF cycle despite a cycle start and an egg retrieval. The number of eggs retrieved was the most significant predictor of having no embryos available for a transfer, with a c-statistic of 0.80 when modeled as the only predictor variable.

CONCLUSION

We derived counseling tools with acceptable discrimination for use in clinical practice (c-statistics > 0.7). Our study further suggests that the number of eggs retrieved from an IVF cycle is most predictive of having 2 or more embryos cryopreserved and not having any embryos after an IVF cycle, suggesting that clinicians should strive to optimize oocyte yield especially in poor prognosis patients. The probability of having two more embryos cryopreserved in a freeze-all IVF cycle such that an embryo selection method is applicable can be predicted with acceptable precision prior to the IVF cycle and excellent precision following egg retrieval using the prediction score.

Ovarian stimulation increases the risk of ectopic pregnancy for fresh embryo transfers: an analysis of 68,851 clinical pregnancies from the Japanese Assisted Reproductive Technology registry

OBJECTIVE

To evaluate the risk of ectopic pregnancies (EPs) for fresh cycles according to different ovarian stimulation protocols.

DESIGN

Registry-based retrospective cohort study.

SETTING

Not applicable.

PATIENT(S)

A total of 68,851 clinical pregnancies after fresh single embryo transfer between 2007 and 2015.

INTERVENTION (S)

None MAIN OUTCOME MEASURE(S): Ectopic pregnancies. Odds ratios and 95% confidence intervals for EPs were calculated by using generalized estimating equations adjusted for potential maternal and treatment characteristics.

RESULT(S)

Among 68,851 clinical pregnancies, 1,049 (1.46%) cases of EP were reported. Compared with natural cycles, all ovarian stimulation protocols were associated with a significantly increased risk of EP. Ovarian stimulation with clomiphene (CC) demonstrated the highest odds ratios for EPs. Significant associations between ovarian stimulation protocols and EP compared with natural cycles were prominent when the number of retrieved oocytes was low (1-3) to moderate (4-7), but there were no significant associations when the number of retrieved oocytes was high (≥8).

CONCLUSION(S)

Ovarian stimulation protocols were significantly associated with an increased risk of EP. In particular, ovarian stimulation with CC had the highest risk of EP compared with other stimulation protocols. Further studies are essential to investigate possible confounding factors for different ovarian stimulation protocols, especially CC, and the risk of EP.

Perinatal and maternal outcomes after frozen versus fresh embryo transfer cycles in women of advanced maternal age

OBJECTIVE

The delay of childbearing in women has become a worldwide issue in recent decades. The application of assisted reproductive technology in women of advanced maternal age (AMA) is increasing. Evidence on the safety and outcomes of frozen embryo transfer (FET) compared with fresh embryo transfer (ET) in AMA women is still lacking. Therefore, the objective of the present study was to compare perinatal and maternal outcomes after autologous FET and fresh ET cycles in women of AMA.

STUDY DESIGN

A retrospective study of 1663 FET and 3964 fresh ET cycles in reproductive medical centers from 2009 to 2014. Women who aged ≥35 years and had clinical pregnancies after autologous frozen or fresh ET were included. The main perinatal outcomes included birth weight, gestational age, rates of preterm birth, macrosomia, low birth weight (LBW), and very low birth weight. The main maternal outcomes included rates of hypertensive disorders of pregnancy, gestational diabetes mellitus, and preterm premature rupture of the membranes.

RESULTS

Women who underwent FET had an increased risk of hypertensive disorders of pregnancy [1.1 % vs. 0.4 %, adjusted OR (95 % CI): 2.76 (1.39-5.51); p = 0.004]. Singletons born after FET had significantly higher mean birth weight (3388.78 ± 538.47 vs. 3316.19 ± 549.08; p = 0.001). Furthermore, increased risk of macrosomia [13.5 % vs. 10.4 %, adjusted OR (95 % CI): 1.35 (1.07-1.71); p = 0.013] and decreased risk of LBW [3.6 % vs. 5.3 %, adjusted OR (95 % CI): 0.67 (0.45-1.00); p = 0.048] were found in singletons born after FET.

CONCLUSIONS

Perinatal risks of AMA patients are higher in FET than in fresh ET, including higher birth weight, risks of macrosomia in singleton births, and hypertensive disorders of pregnancy.

Embryo cryopreservation and utilization in the United States from 2004-2013

Objective

To evaluate the quantity and use of embryos cryopreserved at assisted reproductive technology (ART) clinics in the United States from 2004 through 2013 and to characterize trends in ART cycles in which all embryos were cryopreserved.

Design

Retrospective analysis.

Setting

Not applicable.

Patient(s)

Registry data from the Society for Assisted Reproductive Technology.

Intervention(s)

Historical cohort of U.S. ART cycles reported to the Society for Assisted Reproductive Technology Clinical Outcomes Reporting System between 2004 and 2013.

Main Outcome Measure(s)

Number of embryos cryopreserved and factors associated with having cryopreserved embryos.

Result(s)

The percentage of fresh cycles in which all embryos were frozen increased dramatically each year after 2010: 15.6% (2010), 19.9% (2011), 30.7% (2012), and 40.7% (2013). During 10 years, 1,954,548 embryos were cryopreserved and 717,345 embryos were transferred. In freeze-only cycles from 2004 to 2013, there was a significant increase in the percentage of women with diminished ovarian reserve (19.9% to 34.1%) and in those who used preimplantation genetic testing (3.2% to 6.9%). During the 10-year period, there were 294,575 fresh cycles with embryo transfer and at least one embryo cryopreserved. Overall, 52.5% (n = 154,543) did not undergo a subsequent frozen embryo transfer, 29.5% (n = 40,462) were left with no frozen embryos, 50.4% (n = 68,875) had one–five embryos, and 20.0% (n = 27,396) had ≥six. Factors associated with having excess embryos included donor oocyte cycles and increased antimüllerian hormone levels.

Conclusion(s)

There has been a sharp increase in U.S. ART cycles in which all embryos are frozen and this may result in more embryos in storage.

Higher probability of live-birth in high, but not normal, responders after first frozen-embryo transfer in a freeze-only cycle strategy compared to fresh-embryo transfer: a meta-analysis

STUDY QUESTION

Does the outcome of the comparison of live birth rates between the first frozen embryo transfer (ET) (in a freeze-only cycles strategy, i.e. frozen ET group) and a fresh embryo transfer (fresh ET group) differ considering the type of ovarian response?

SUMMARY ANSWER

Α significantly higher probability of live birth is present in high, but not normal, responders, after the first frozen ET in a freeze-only cycle strategy as compared to a fresh ET.

WHAT IS KNOWN ALREADY

It has been hypothesised that freezing all good embryos in a fresh in-vitro fertilisation (IVF) cycle and deferring embryo transfer in subsequent cycles may provide a more physiological endometrial environment for embryo implantation when compared to a fresh ET. However, currently, three relevant meta-analyses have been published with conflicting results, while none of them has taken into consideration the type of ovarian response. Recently, the publication of additional, large relevant randomised controlled trials (RCTs) in patients with different types of ovarian response makes possible the comparative evaluation of the first frozen ET (in a freeze-only cycle strategy) versus fresh ET, considering the type of ovarian response.

STUDY DESIGN, SIZE, DURATION

A systematic review and meta-analysis was performed aiming to identify RCTs comparing the first frozen ET (in a freeze-only cycle strategy) to a fresh ET. The main outcome was live birth, while secondary outcomes included ongoing pregnancy, clinical pregnancy, moderate/severe ovarian hyperstimulation syndrome (OHSS) and miscarriage.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We identified eight eligible RCTs, including 5265 patients, which evaluated the first frozen ET in a freeze-only cycle strategy versus a fresh ET either in high responders (n = 4) or in normal responders (n = 4). No relevant RCTs were present in poor responders. Meta-analysis of weighted data using fixed and random effects model was performed. Results are reported as relative risk (RR) with 95% confidence interval (CI).

MAIN RESULTS AND THE ROLE OF CHANCE

Eligible RCTs were published between 2011 and 2018. Four RCTs (n = 3255 patients) compared the first frozen ET (in a freeze-only cycle strategy) to a fresh ET in normal responders and four RCTs (n = 2010 patients) did the comparison in high responders. In high responders, a significantly higher probability of live birth was observed in the frozen ET group when compared with the fresh ET group (RR: 1.18, 95% CI: 1.06-1.31; fixed effects model; heterogeneity: I2 = 0%; three studies; n = 3398 patients). However the probability of live birth was not significantly different between the frozen ET group and the fresh ET group in normal responders (RR: 1.13, 95% CI: 0.90-1.41; random effects model; heterogeneity: I2 = 77%; three studies; n = 1608 patients). The risk of moderate/severe OHSS was significantly lower in the frozen ET group when compared with the fresh ET group both in high (RR: 0.19, 95% CI: 0.10-0.37; fixed effects model; heterogeneity: not applicable; a single study; n = 1508 patients) and normal responders (RR: 0.39, 95% CI: 0.19-0.80; fixed effects model; heterogeneity: I2 = 0%; two studies; n = 2939 patients).

LIMITATIONS, REASONS FOR CAUTION

Considerable heterogeneity was present among the studies, regarding ovarian stimulation protocols and the triggering signal used for inducing final oocyte maturation as well as the cryopreservation methods, while the quality of evidence was poor for the live birth rate in high responders. Moreover, the analysis did not apply a standard for determining 'high' or 'normal' responders since the type of ovarian response followed the characterisation of populations as reported by the authors of the eligible studies.

WIDER IMPLICATIONS OF THE FINDINGS

A freeze-only cycle strategy should be the preferred option in high responders since it enhances the probability of live birth, while reducing the chance of moderate/severe OHSS. In normal responders, the same strategy could be applied, in the interest of patient safety or clinic convenience, without compromising the chances of live birth.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used and there were no competing interests.

PROSPERO REGISTRATION NUMBER

PROSPERO registration number: CRD42018099389.

Impact of elective frozen vs. fresh embryo transfer strategies on cumulative live birth: Do deleterious effects still exist in normal & hyper responders?

Background

Is freeze-all strategy effective in terms of cumulative live birth rates (CLBRs) in all patients?

Methods

This retrospective single-center study analyzed the CLBRs of 2523 patients undergoing fresh or electively frozen blastocyst transfer cycles. In 1047, cycles, the fresh embryo transfer (ET) strategy was applied for the 1^st ET, whereas electively frozen ET (e-FET) was performed in 1476 cycles. Female age ≤ 37 and blastocysts frozen via vitrification were included. The patients in each arm were further stratified into four subgroups according to the number of oocytes retrieved as follows: Group A: 1–5, group B: 6–10, group C: 11–15 and group D: 16–25 oocytes retrieved. The primary endpoint was the CLBR. The secondary endpoints were the ovarian hyperstimulation syndrome (OHSS) rate and the live birth rates (LBRs) following fresh ETs and e-FETs for the first transfers.

Result(s)

The CLBR was similar between the fresh ET and e-FET arms in group A (35/76 (46.1%) vs 29/67 (43.3%), p = 0.74) and group B (165/275 (60%) vs 216/324 (66.7%), p = 0.091), whereas significantly higher rates were detected in favor of the e-FET arm within group C (328/460 (71.3%) vs 201/348 (57.8%), p<0.001) and group D (227/348 (65.2%), vs 446/625 (71.5%), p<0.001). The OHSS rate was also found to be higher in the fresh ET arm among group C (12/348 (3.4%) vs 0/460 (0%), p<0.001) and group D (38/348 (10.9%) vs 3/625 (0.5%), p<0.001) patients than e-FET arm. Perinatal and obstetrical outcomes were nonsignificantly different between fresh and e-FET arms. However, the birth weights were significantly lower for fresh ET, 3064 versus 3201 g for singletons (p<0.001)

Conclusion

Compared with a fresh-transfer strategy, the e-FET strategy resulted in a higher CLBR among patients with >10 oocytes retrieved during stimulated cycles.

GnRH triggering may improve euploidy and live birth rate in hyper-responders: a retrospective cohort study

PURPOSE

Despite the increasing use of GnRHa to trigger final oocyte maturation in segmented IVF cycles, the effects of trigger modality on chromosomal competence and embryo quality remain controversial. Hence, the purpose of this study was to compare euploidy rates and pregnancy outcomes among hyper-responding women using hCG versus GnRHa trigger.

METHODS

This retrospective study included 333 hyper-responders, defined as >15 oocytes retrieved, who underwent preimplantation genetic testing (PGT-A) in segmented IVF cycles using either GnRHa or urinary hCG trigger. Live birth rate (LBR) was the primary outcome of interest. Implantation rate (IR), clinical pregnancy rate (CPR), and euploidy rate were secondary outcomes.

RESULTS

GnRH triggering was associated with improved IR (70.5 vs. 53.2%, p = 0.0475), LBR (51.3 vs. 33.8%, p = 0.0170) compared to hCG. A greater number of oocytes were retrieved (21.9 vs 18.4%, p < 0.001) and euploid embryos produced (2.8 vs. 2.1, p = 0.0109) after GnRHa triggering, while higher euploidy rates were only observed among women <35-years-old (62.0 vs. 51.7%, p = 0.0307) using GnRHa trigger. Higher OHSS rates were observed after hCG triggering (10.6 vs. 2.1%, p = 0.0009).

CONCLUSION

Hyper-responders who received GnRHa trigger experienced improved pregnancy outcomes and lower rates of OHSS compared to hCG triggering. The higher number of oocytes retrieved and euploid embryos produced may reflect an improved developmental competence using GnRHa triggering due to physiologic induction of both LH and FSH surge or other undefined mechanisms that improve embryo development. However, higher overall euploid rates were only observed among women <35-years-old using the GnRHa trigger. Further prospective studies are required to validate this observation and evaluate the specific influence of different ovulation triggers on gamete developmental competence among hyper-responder women.

Dydrogesterone-primed ovarian stimulation is an effective alternative to gonadotropin-releasing hormone antagonist protocol for freeze-all cycles in polycystic ovary syndrome

OBJECTIVE

To compare the effects of progestin-primed ovarian stimulation using dydrogesterone (DYD) and a gonadotropin-releasing hormone (GnRH) antagonist protocol on cycle characteristics and pregnancy rates in freeze-all cycles in patients with polycystic ovary syndrome (PCOS).

METHODS

Medical records of PCOS patients who underwent freeze-all in vitro fertilization cycles between April 2017 and April 2019 at the Novafertil in vitro fertilization Center were retrospectively evaluated. The primary outcome measure was the incidence of premature luteinizing hormone surge. Secondary outcome measures were the total number of mature oocytes retrieved, fertilization rate, clinical pregnancy rates and ongoing pregnancy rates.

RESULTS

A total of 525 patients were included in the study. DYD-primed ovarian stimulation and a GnRH antagonist protocol were applied in 258 and 267 patients, respectively. The baseline parameters were similar between the two groups. The numbers of mature and fertilized oocytes were similar in the cetrorelix (CET) group and DYD group (11.43 ± 3.48 vs. 11.29 ± 4.34, respectively, P = 0.692; and 8.98 ± 2.93 vs. 8.62 ± 3.67, respectively, P = 0.208). Premature luteinization was rare in both groups, and the difference between the groups was not statistically significant (2.9% vs. 1.5%, respectively, P = 0.268). There was no significant difference in clinical pregnancy rate of the first frozen embryo transfer cycle between the DYG group and the CET group (56% [120/214] vs. 55.6% [113/203], respectively, P = 0.283). There were no significant differences in biochemical pregnancy rates, implantation rates, miscarriage rates or ongoing pregnancy rates between the two groups (P > 0.05).

CONCLUSION

Dydrogesterone-primed ovarian stimulation seems to be an effective alternative to the GnRH antagonist protocol for freeze-all cycles in PCOS patients.

Endometrial thickness is associated with incidence of small-for-gestational-age infants in fresh in vitro fertilization-intracytoplasmic sperm injection and embryo transfer cycles

OBJECTIVE

To investigate whether endometrial thickness (EMT) is associated with adverse obstetric and neonatal outcomes in fresh in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET) cycles.

DESIGN

Retrospective cohort study.

SETTING

University-based reproductive medical center.

PATIENT(S)

Women under the age of 42 years who underwent IVF/ICSI treatment and received fresh ET in our unit from January 2017 to December 2018, resulting in a live singleton birth.

INTERVENTION(S)

Controlled ovarian hyperstimulation and IVF/ICSI; fresh ET.

MAIN OUTCOME MEASURE(S)

Birth weight, gestational age, small for gestational age (SGA), large for gestational age (LGA), placenta previa, placental abruption, hypertensive disorders, and gestational diabetes mellitus.

RESULT(S)

The risk of being born SGA was statistically significantly increased in the EMT ≤7.5 mm group compared with those from the EMT >12 mm group (adjusted odds ratio [aOR] 2.391; 95% confidence interval [CI], 1.155-4.950). Moreover, maternal body mass index, secondary infertility, preterm delivery, and hypertensive disorders were all independent predictors for SGA. The mean birth weights of singletons in women with EMT ≤7.5 mm were lower than in the groups with EMT >7.5-12 mm and EMT >12 mm (3.25 ± 0.56 kg vs. 3.38 ± 0.51 kg and 3.39 ± 0.53 kg, respectively).

CONCLUSION(S)

After fresh IVF/ICSI-ET, the risk of SGA was increased twofold in women with EMT ≤7.5 mm compared with women with EMT >12 mm. We suggest that women with a thin EMT after obtaining a pregnancy by IVF should receive improved prenatal care to reduce the risk of delivering a SGA infant.

Factors associated with extremely high progesterone concentrations on the day of HCG administration

OBJECTIVE

Progesterone elevation on the day of human chorionic gonadotropin (hCG) administration remains one of the most controversial topics in reproductive endocrinology. Factors associated with these increases have not been fully determined. The purpose of our study is to investigate factors associated with extreme progesterone elevation on the day of human chorionic gonadotropin (hCG) administration.

MATERIALS AND METHODS

This retrospective observational, single-center cohort study recruited 2000 fresh in vitro fertilization (IVF) and/or intracytoplasmic sperm injection(ICSI)-embryo transfer cycles from January 2000 to December 2014 in our institution.

RESULTS

When cycles were divided into those with progesterone <1.94 ng/mL (n = 1791) and ≧1.94 ng/mL (n = 209) on the day of hCG administration, five factors were positively associated with highly elevated progesterone concentration: protocol (GnRH agonist versus antagonist; odds ratio [OR = 2.786]), number of dominant follicles (OR = 1.098), total dose of follicle stimulating hormone (FSH) used (OR = 1.023), elevated luteinizing hormone (LH) (OR = 1.085) and estradiol (E2; OR = 1.001) concentrations on the day of hCG administration (p < 0.001 each). After omitting the protocol effect, the remaining factors showed limited contributions to highly elevated progesterone (ORs = 0.95-1.2).

CONCLUSIONS

The factor showing the greatest association with extreme progesterone elevation was use of the GnRH agonist protocol.

Association between the number of oocytes retrieved and neonatal outcomes after freeze-all IVF cycles

STUDY QUESTION

Is there any association between the number of oocytes retrieved and neonatal outcomes following IVF/ICSI treatment for patients using a freeze-all strategy?

SUMMARY ANSWER

There was no increased risk of adverse neonatal outcomes in cycles with high number of oocytes retrieved (≥ 16) compared to those with 10-15 oocytes retrieved in freeze-all cycles.

WHAT IS KNOWN ALREADY

Recent studies have found that there is an increased risk of preterm birth (PTB, <37 weeks gestation) and low birth weight (LBW, <2500 g) following IVF in women with a high number (>20) of oocytes retrieved in fresh embryo transfer (ET) cycles. Other studies have found that there is an association between the number of oocytes retrieved and placenta praevia. However, the association between the number of oocytes retrieved and neonatal outcomes when using a freeze-all strategy is unknown.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study included 14 170 women with singleton deliveries achieved by a freeze-all strategy performed between November 2006 and December 2017 in China. Only the first delivery from one episode of ovarian stimulation was included.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Only cycles using a freeze-all strategy performed during the study period and resulting in singleton live births were included. Patients were categorized into five groups according to the number of oocytes retrieved: 1-3, 4-9, 10-15, 16-20 or >20 oocytes. In univariate and multivariate logistic regression analysis of the association between ovarian response and the outcomes of PTB, early PTB, LBW and other neonatal outcomes, the 10 to 15 oocyte category was used as a reference and other four groups were analysed as dummy variables. Multiple linear regression analysis was used to evaluate possible associations of birth weight z-scores and the number of oocytes retrieved (analysed as a continuous variable) with other confounding factors.

MAIN RESULTS AND THE ROLE OF CHANCE

After adjusted for confounding factors, no significant differences were observed in the risk of PTB (P = 0.837), LBW (P = 0.974), early PTB (P = 0.341), very LBW (P = 0.848), congenital malformation (P = 0.916) and other adverse neonatal outcome among patients with different number of oocytes retrieved. There was a higher risk of early PTB among women with a poor ovarian response (1-3 oocytes) compared with women with a normal response (10-15 oocytes) (1.5% vs 0.8%), crude odds ratio (OR): 2.001, 95% CI: 1.159-3.465, P = 0.013. However, the difference was not significant after adjusting for confounders, adjusted OR: 1.753, 95% CI: 0.997-3.081, P = 0.051.

LIMITATIONS, REASONS FOR CAUTION

Data on some known confounders such as smoking and medical history of gestational diabetes mellitus and preeclampsia were lacking. As with any retrospective study, unknown confounders may affect outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

In the freeze-all cycles, there was no association between number of oocytes retrieved and adverse neonatal outcomes. This is a reassuring finding for both clinicians and patients who are planning to use freeze-all cycles for a variety of indications.

STUDY FUNDING/COMPETING INTEREST(S)

Grants from the National Natural Science Foundation of China (NSFC) (31770989 to Y.W.) and the Shanghai Ninth People's Hospital Foundation of China (JYLJ030 to Y.W.). None of the authors have any conflicts of interest to declare.