Cryopreservation of human embryos and its contribution to in vitro fertilization success rates

Livebirth rate after one frozen embryo transfer in ovulatory women starting with natural, modified natural, or artificial endometrial preparation in Viet Nam: an open-label randomised controlled trial

BACKGROUND

Use of frozen embryo transfer (FET) in in-vitro fertilisation (IVF) has increased. However, the best endometrial preparation protocol for FET cycles is unclear. We compared natural and modified natural cycle strategies with an artificial cycle strategy for endometrial preparation before FET.

METHODS

In this randomised, open-label study, we recruited ovulatory women aged 18-45 years at a hospital in Ho Chi Minh City, Viet Nam, who were randomly allocated (1:1:1) to natural, modified natural, or artificial cycle endometrial preparation using a computer-generated random list and block randomisation. The trial was not masked due to the nature of the study interventions. In natural cycles, no oestrogen, progesterone, or human chorionic gonadotropin (hCG) was used. In modified natural cycles, hCG was used to trigger ovulation. In artificial cycles, oral oestradiol valerate (8 mg/day from day 2-4 of menstruation) and vaginal progesterone (800 mg/day starting when endometrial thickness was ≥7 mm) were used. Embryos were vitrified, and then one or two day-3 embryos or one day-5 embryo were warmed and transferred under ultrasound guidance. If the first FET cycle was cancelled, subsequent cycles were performed with artificial endometrial preparation. The primary endpoint was livebirth after one FET. This trial is registered at ClinicalTrials.gov, NCT04804020.

FINDINGS

Between March 22, 2021, and March 14, 2023, 4779 women were screened and 1428 were randomly assigned (476 to each group). 99 first FET cycles were cancelled in each of the natural and modified cycle groups, versus none in the artificial cycle group. The livebirth rate after one FET was 174 (37%) of 476 in the natural cycle strategy group, 159 (33%) of 476 in the modified natural cycle strategy group, and 162 (34%) of 476 in the artificial cycle strategy group (relative risk 1·07 [95% CI 0·87-1·33] for natural vs artificial cycle strategy, and 0·98 [0·79-1·22] for modified natural vs artificial cycle strategy). Maternal and neonatal outcomes did not differ significantly between groups, as the power to detect small differences was low.

INTERPRETATION

Although the livebirth rate was similar after natural, modified natural, and artificial cycle endometrial preparation strategies in ovulatory women undergoing FET IVF, no definitive conclusions can be made regarding the comparative safety of the three approaches.

FUNDING

None.

Factors Associated With Mosaicism in Human Embryos: A Retrospective Study

Objective This study aims to identify factors associated with mosaicism in human embryos at Hung Vuong Hospital. Methods We performed a retrospective analysis of data from 2018 to 2022, approved by the Hung Vuong Hospital Ethics Committee (CS/HV/23/15). We analyzed variables such as demographic characteristics, clinical measurements, and in-vitro fertilization (IVF) cycle outcomes to investigate their relationship with embryo mosaicism. Results A total of 73 couples undergoing IVF with preimplantation genetic testing (PGT) were included in the analysis. Among 308 embryos, 98 (31.8%) were mosaic, 124 (40.3%) were euploid, and 86 (27.9%) were aneuploid. Univariable analysis revealed that female age was significantly associated with increased odds of mosaicism (odd ratio (OR) = 1.11, 95% confidence interval (CI): 1.04 - 1.19, p = 0.003). Male age demonstrated a marginal association with mosaicism (OR = 1.05, 95% CI: 1.00 - 1.11, p = 0.07). Other factors, including body mass index (BMI), anti-Mullerian hormone (AMH) levels, blood types, and sperm quality, were not significantly associated with mosaicism. In the multivariable analysis, controlling for both female and male age, female age showed a trend toward significance (OR = 1.12, 95% CI: 1.02 - 1.23, p = 0.02), while male age showed no significant effect (OR = 0.99, 95% CI: 0.92 - 1.06, p = 0.75). Conclusions The findings suggest that female age is a critical factor influencing the occurrence of mosaicism in embryos. Further research is needed to fully understand the mechanisms underlying mosaicism in human embryos.

Oral medroxyprogesterone acetate for the use of ovulation suppression in in vitro fertilization: a cohort trial

OBJECTIVE

To broadly assess the efficacy of medroxyprogesterone acetate (MPA) for ovulatory suppression during in vitro stimulation compared with gonadotropin-releasing hormone (GnRH) antagonist cycles.

DESIGN

Cohort trial.

SETTING

A single academic-affiliated private fertility practice.

PATIENTS

Patients of all diagnoses aged 18-44 years undergoing autologous in vitro fertilization (IVF) for fertility treatment between 2020 and 2023.

INTERVENTIONS

Comparison of MPA vs. antagonist IVF stimulation cycles.

MAIN OUTCOME MEASURES

Rates of premature ovulation, oocyte and embryo yield, embryo quality, pregnancy rates, and logistical benefits.

RESULTS

Prospective data was collected on 418 patients who underwent MPA protocol ovarian stimulation (MPA group), which was compared with 419 historical control gonadotropin hormone-releasing hormone antagonist cycles (control group). Age was similar between groups (35.6 ± 4.6 vs. 35.7 ± 4.8 years; P = .75). There were no cases of premature ovulation in the MPA group compared with a total of five cases in the control group (0% vs. 1.2%; risk ratio [RR] = 0.09; 95% confidence interval [CI], 0.01, 1.66). No differences were seen between number of oocytes retrieved (14.3 ± 10.2 vs. 14.3 ± 9.7; P = .83), blastocysts (4.9 ± 4.6 vs. 5.0 ± 4.6; P = .89), or euploid blastocysts (2.4 ± 2.6 vs. 2.2 ± 2.4; P = .18) in the MPA vs. control group respectively. Clinical pregnancy rate was similar between groups (70.4% vs. 64.2%; RR = 0.92; 95% CI, 0.72, 1.18). There was no difference in length of IVF stimulation or dose of stimulation medications. Patients in the MPA group saved an average of $491 ± $119 on medications, had an average of one less monitoring visit (4.4 ± 0.9 vs. 5.6 ± 1.1; P<.01), and 5.0 ± 1.2 less injections per cycle. When adjusting for age and ovarian reserve, protocol group (MPA vs. control) did not influence having an embryo available for transfer (76.6% vs. 73.4%; adjusted RR = 1.05; 95% CI, 0.94, 1.14).

CONCLUSION

For ovulatory suppression during IVF cycles, MPA was effective at preventing ovulation while demonstrating similar cycle and reproductive outcomes, with the additional benefits of patient cost savings, increased convenience with decreased number of visits, and fewer injections.

BRCA Mutations and Fertility Preservation

Hereditary cancers mostly affect the adolescent and young adult population (AYA) at reproductive age. Mutations in BReast CAncer (BRCA) genes are responsible for the majority of cases of hereditary breast and ovarian cancer. BRCA1 and BRCA2 act as tumor suppressor genes as they are key regulators of DNA repair through homologous recombination. Evidence of the accumulation of DNA double-strand break has been reported in aging oocytes, while BRCA expression decreases, leading to the hypothesis that BRCA mutation may impact fertility. Moreover, patients exposed to anticancer treatments are at higher risk of fertility-related issues, and BRCA mutations could exacerbate the treatment-induced depletion of the ovarian reserve. In this review, we summarized the functions of both genes and reported the current knowledge on the impact of BRCA mutations on ovarian ageing, premature ovarian insufficiency, female fertility preservation strategies and insights about male infertility. Altogether, this review provides relevant up-to-date information on the impact of BRCA1/2 mutations on fertility. Notably, BRCA-mutated patients should be adequately counselled for fertility preservation strategies, considering their higher sensitivity to chemotherapy gonadotoxic effects.

The cumulative live birth rates of 18 593 women with progestin-primed ovarian stimulation-related protocols and frozen-thawed transfer cycles

STUDY QUESTION

What are the odds of achieving pregnancy when adopting progestin-primed ovarian stimulation (PPOS)-related protocols combined with repetitive frozen-thawed transfer (FET) cycles in patients with different clinical characteristics?

SUMMARY ANSWER

The cumulative live birth rates (CLBRs) of women undergoing different PPOS-related protocols can be significantly and consistently enhanced within six FET cycles when the female age is <40 years (or even <45 years) and when >5 oocytes are retrieved, regardless of antral follicle count (AFC).

WHAT IS KNOWN ALREADY

There have been numerous studies on the live birth rate of the first FET cycle in patients with PPOS-related protocols. These studies have focused mainly on comparing pregnancy outcomes with those of other stimulation protocols. However, owing to the unique features of the PPOS-related strategy, such as its flexible timing of oocyte retrieval and repeated transfer of frozen embryos, studies using the CLBR as an overall indicator of success and investigating which types of patients would benefit from this protocol are lacking.

STUDY DESIGN SIZE DURATION

This retrospective cohort study included 18 593 women who underwent PPOS-related protocols (dydrogesterone + hMG, medroxyprogesterone acetate + hMG, micronized progesterone + hMG treatment, and luteal-phase ovarian stimulation protocol) from 1 March 2011 to 31 September 2022 in our centre.

PARTICIPANTS/MATERIALS SETTING METHODS

The population was categorized by female age, number of oocytes retrieved, and AFC in the analysis of CLBR within six FET cycles. The age groups (Groups 1-5, respectively) were <30, 30-34, 35-39, 40-44, and ≥45 years. The number of oocytes retrieved was grouped as 1-5, 6-10, 11-15, 16-20, and >20. AFC was grouped as <5, 5-10, 11-15, and >15. The Kaplan-Meier analysis (optimistic method), which hypothesized that patients who did not continue treatment had the same chance of achieving a live birth as those who continued, and the competing risk method (conservative method) which hypothesized they had no chance of achieving a live birth, were applied. In further analyses, the Cox model and Fine-Gray model were adopted: the former corresponds to the optimistic scenario, and the latter corresponds to the pessimistic scenario.

MAIN RESULTS AND THE ROLE OF CHANCE

CLBR had a declining trend with female age over six FET cycles (Groups 1-5, respectively: optimistic: 96.9%, 96.6%, 91.4%, 67.3%, and 11.7%; conservative: 87.3%, 85.0%, 74.0%, 41.3%, and 7.5%), requiring more FET cycles to achieve a success rate of at least 50% (Groups 1-5, respectively: optimistic: 2, 2, 2, 4, and >6 cycles; conservative: 2, 2, 2, >,6 and >6 cycles). CLBR showed an increasing trend with the number of oocytes retrieved (Groups 1-5, respectively: optimistic: 93.8%, 94.3%, 95.8%, 96.0%, and 95.6%; conservative: 66.2%, 78.3%, 85.6%, 88.9%, and 91.0%). All groups needed the same number of FET cycles to achieve a success rate of at least 50% (Groups 1-5, respectively: optimistic: 2, 2, 2, 2, and 2 cycles; conservative: 2, 2, 2, 2, and 2 cycles). Furthermore, the CLBR within six FET cycles had an increasing trend with AFC number (Groups 1-4, respectively: optimistic: 89.2%, 94.8%, 95.9%, and 96.3%; conservative: 67.4%, 78.2%, 83.9%, and 88.1%), with all four groups achieving a success rate of at least 50% by the second FET cycle.

LIMITATIONS REASONS FOR CAUTION

The current research is limited by its retrospective design and single-centre nature, which may restrict the generalizability of our findings.

WIDER IMPLICATIONS OF THE FINDINGS

This work describes two models (the Kaplan-Meier analysis and the competing risk method) to evaluate the clinical outcome of patients using PPOS-related protocols, which are especially useful for patients of advanced age or those with diminished ovarian reserve. Our findings encourage patients below 45 years old, especially younger than 40 years, and patients with lower AFCs and fewer retrieved oocytes to try this new protocol. Moreover, this study demonstrates the degree of improvement in the CLBR within six FET cycles for patients with different clinical characteristics, providing a valuable point of reference to determine whether to continue ART after a transfer failure.

STUDY FUNDING/COMPETING INTERESTS

The study was supported by grants from the National Natural Science Foundation of China (82071603 to L.W., 82001502 to Y.L.). There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

The effects of different endometrial preparation regimens on pregnancy outcomes in frozen-thawed embryo transfer cycles: a prospective randomized controlled study

OBJECTIVE

An increasing number of research have emerged to compare the pregnancy outcomes between the natural cycle and the hormone replacement therapy (HRT) cycle in preparing the endometrium for frozen-thawed embryo transfer (FET), but the results are controversial. This prospective randomized controlled study was hence designed to obtain more solid evidence.

MATERIALS AND METHODS

In this study, patients with regular menstrual cycle length (21-35 days) who underwent FET between January 2010 to December 2017 were recruited for this study. Upon further filtering with the selection criteria of patients being, a total of 405 patients were recruited and randomized. Finally, analysis was performed on 384 patients: 178 belonged to the natural cycle group whereas the remaining 206 were in the HRT group. The primary outcome was live birth rate, while the secondary outcomes were implantation rate, clinical pregnancy rate, early miscarriage rate, late miscarriage rate, multiple birth rate and low birth weight rate.

RESULTS

The live birth rate (37.6% vs 30.1%, p = 0.119) of natural cycle group were higher than those of the hormone replacement therapy group, although the difference was not significant. The secondary outcomes were not found to differ significantly between the two groups. Nonetheless, the endometrium was found to be thicker in the natural cycle group (10.75 mm) than the HRT group (9.00 mm) (p < 0.001).

CONCLUSION

No significant differences were observed between the pregnancy outcomes of the natural cycle group and the HRT group which comprised of patients with regular menstrual cycle length.

External validation of models for predicting cumulative live birth over multiple complete cycles of IVF treatment

STUDY QUESTION

Can two prediction models developed using data from 1999 to 2009 accurately predict the cumulative probability of live birth per woman over multiple complete cycles of IVF in an updated UK cohort?

SUMMARY ANSWER

After being updated, the models were able to estimate individualized chances of cumulative live birth over multiple complete cycles of IVF with greater accuracy.

WHAT IS KNOWN ALREADY

The McLernon models were the first to predict cumulative live birth over multiple complete cycles of IVF. They were converted into an online calculator called OPIS (Outcome Prediction In Subfertility) which has 3000 users per month on average. A previous study externally validated the McLernon models using a Dutch prospective cohort containing data from 2011 to 2014. With changes in IVF practice over time, it is important that the McLernon models are externally validated on a more recent cohort of patients to ensure that predictions remain accurate.

STUDY DESIGN, SIZE, DURATION

A population-based cohort of 91 035 women undergoing IVF in the UK between January 2010 and December 2016 was used for external validation. Data on frozen embryo transfers associated with these complete IVF cycles conducted from 1 January 2017 to 31 December 2017 were also collected.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data on IVF treatments were obtained from the Human Fertilisation and Embryology Authority (HFEA). The predictive performances of the McLernon models were evaluated in terms of discrimination and calibration. Discrimination was assessed using the c-statistic and calibration was assessed using calibration-in-the-large, calibration slope, and calibration plots. Where any model demonstrated poor calibration in the validation cohort, the models were updated using intercept recalibration, logistic recalibration, or model revision to improve model performance.

MAIN RESULTS AND THE ROLE OF CHANCE

Following exclusions, 91 035 women who underwent 144 734 complete cycles were included. The validation cohort had a similar distribution age profile to women in the development cohort. Live birth rates over all complete cycles of IVF per woman were higher in the validation cohort. After calibration assessment, both models required updating. The coefficients of the pre-treatment model were revised, and the updated model showed reasonable discrimination (c-statistic: 0.67, 95% CI: 0.66 to 0.68). After logistic recalibration, the post-treatment model showed good discrimination (c-statistic: 0.75, 95% CI: 0.74 to 0.76). As an example, in the updated pre-treatment model, a 32-year-old woman with 2 years of primary infertility has a 42% chance of having a live birth in the first complete ICSI cycle and a 77% chance over three complete cycles. In a couple with 2 years of primary male factor infertility where a 30-year-old woman has 15 oocytes collected in the first cycle, a single fresh blastocyst embryo transferred in the first cycle and spare embryos cryopreserved, the estimated chance of live birth provided by the post-treatment model is 46% in the first complete ICSI cycle and 81% over three complete cycles.

LIMITATIONS, REASONS FOR CAUTION

Two predictors from the original models, duration of infertility and previous pregnancy, which were not available in the recent HFEA dataset, were imputed using data from the older cohort used to develop the models. The HFEA dataset does not contain some other potentially important predictors, e.g. BMI, ethnicity, race, smoking and alcohol intake in women, as well as measures of ovarian reserve such as antral follicle count.

WIDER IMPLICATIONS OF THE FINDINGS

Both updated models show improved predictive ability and provide estimates which are more reflective of current practice and patient case mix. The updated OPIS tool can be used by clinicians to help shape couples' expectations by informing them of their individualized chances of live birth over a sequence of multiple complete cycles of IVF.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by an Elphinstone scholarship scheme at the University of Aberdeen and Aberdeen Fertility Centre, University of Aberdeen. S.B. has a commitment of research funding from Merck. D.J.M. and M.B.R. declare support for the present manuscript from Elphinstone scholarship scheme at the University of Aberdeen and Assisted Reproduction Unit at Aberdeen Fertility Centre, University of Aberdeen. D.J.M. declares grants received by University of Aberdeen from NHS Grampian, The Meikle Foundation, and Chief Scientist Office in the past 3 years. D.J.M. declares receiving an honorarium for lectures from Merck. D.J.M. is Associate Editor of Human Reproduction Open and Statistical Advisor for Reproductive BioMed Online. S.B. declares royalties from Cambridge University Press for a book. S.B. declares receiving an honorarium for lectures from Merck, Organon, Ferring, Obstetric and Gynaecological Society of Singapore, and Taiwanese Society for Reproductive Medicine. S.B. has received support from Merck, ESHRE, and Ferring for attending meetings as speaker and is on the METAFOR and CAPRE Trials Data Monitoring Committee.

TRIAL REGISTRATION NUMBER

N/A.

Finding of the optimal preparation and timing of endometrium in frozen-thawed embryo transfer: a literature review of clinical evidence

Frozen-thawed embryo transfer (FET) has been a viable alternative to fresh embryo transfer in recent years because of the improvement in vitrification methods. Laboratory-based studies indicate that complex molecular and morphological changes in endometrium during the window of implantation after exogenous hormones with controlled ovarian stimulation may alter the interaction between the embryo and endometrium, leading to a decreased implantation potential. Based on the results obtained from randomized controlled studies, increased pregnancy rates and better perinatal outcomes have been reported following FET. Compared to fresh embryo transfer, fewer preterm deliveries, and reduced incidence of ovarian hyperstimulation syndrome were found after FETs, yet there is a trend of increased pregnancy-related hypertensive diseases in women receiving FET. Despite the increased application of FET, the search for the most optimal priming protocol for the endometrium is still undergoing. Three available FET protocols have been proposed to prepare the endometrium: i) natural cycle (true natural cycle and modified natural cycle) ii) artificial cycle (AC) or hormone replacement treatment cycle iii) mild ovarian stimulation (mild-OS) cycle. Emerging evidence suggests that the optimal timing for FET using warmed blastocyst transfer is the LH surge+6 day, hCG administration+7 day, and the progesterone administration+6 day in the true natural cycle, modified natural cycle, and AC protocol, respectively. Although still controversial, better clinical pregnancy rates and live birth rates have been reported using the natural cycle (true natural cycle/modified natural cycle) compared with the AC protocol. Additionally, a higher early pregnancy loss rate and an increased incidence of gestational hypertension have been found in FETs using the AC protocol because of the lack of a corpus luteum. Although the common clinical practice is to employ luteal phase support (LPS) in natural cycles and mild-OS cycles for FET, the requirement for LPS in these protocols remains equivocal. Recent findings obtained from RCTs do not support the routine application of endometrial receptivity testing to optimize the timing of FET. More RCTs with rigorous methodology are needed to compare different protocols to prime the endometrium for FET, focusing not only on live birth rate, but also on maternal, obstetrical, and neonatal outcomes.

Review of Endometrial Receptivity Array: A Personalized Approach to Embryo Transfer and Its Clinical Applications

Successful outcomes of in vitro fertilization (IVF) rely on both the formation of a chromosomally normal embryo and its implantation in a receptive endometrium. Pre-implantation genetic testing for aneuploidy (PGT-A) has been widely accepted as a tool to assess the viability of an embryo. In 2011, the endometrial receptivity array (ERA) was first published as a tool to determine when the endometrium is most receptive to an embryo, commonly referred to as the "window of implantation" (WOI). The ERA uses molecular arrays to assess proliferation and differentiation in the endometrium and screens for inflammatory markers. Unlike PGT-A, there has been dissent within the field concerning the efficacy of the ERA. Many studies that contest the success of the ERA found that it did not improve pregnancy outcomes in patients with an already-good prognosis. Alternatively, studies that utilized the ERA in patients with repeated implantation failure (RIF) and transfer of known euploid embryos demonstrated improved outcomes. This review aims to describe the ERA as a novel technique, review the various settings that the ERA may be used in, such as natural frozen embryo transfer (nFET) and hormone replacement therapy frozen embryo transfer (HRT-FET), and provide a summary of the recent clinical data for embryo transfers in patients with RIF utilizing the ERA.

Patient- and cycle-specific factors affecting the outcome of frozen-thawed embryo transfers

PURPOSE

This study attempted at identifying the main parameters influencing the outcome of frozen embryo transfers.

METHODS

This is a single-center retrospective cohort study of 830 frozen-embryo-transfer cycles performed at a German university hospital from January 2012 to December 2016. Main outcome parameters were the clinical pregnancy and live birth rate. Twelve patient- and cycle-dependent factors were analyzed in terms of their influence on the outcome of frozen embryo transfers. Multivariate logistic regression analysis was used for the modelling of the dependency of the different parameters on outcomes.

RESULTS

The clinical pregnancy rate in our study was 25.5%, the live birth rate was 16.1% with an average maternal age of 34.2 years at the time of the oocyte retrieval. In the univariate analysis age, number of transferred embryos, blastocyst versus cleavage stage transfer, embryo quality and mode of endometrial preparation affected the birth rate significantly. The birth rate after artificial endometrial preparation was significantly lower than the birth rate after transfers in modified natural cycles (12.8 versus 20.6% with p = 0.031). The multivariate logistic regression analysis showed a significant independent influence of age, number of transferred embryos, culture duration and mode of endometrial preparation on the frozen embryo transfer success rates. Body mass index, nicotine abuse, a history of PCO syndrome or endometriosis and the co-transfer of a second poor-quality embryo to a good-quality embryo appeared to be irrelevant for the outcome in our collective.

CONCLUSION

Age, number of transferred embryos, embryo culture duration and the mode of endometrial preparation are independent predictive factors of frozen embryo transfer outcomes.

An all-37 °C thawing method improves the clinical outcomes of vitrified frozen-thawed embryo transfer: a retrospective study using a case-control matching analysis

PURPOSE

The purpose of this study is to assess the impact of different temperatures and incubation times on the clinical outcomes of FET cycles during the thawing procedure and to select a better thawing method to improve clinical outcomes.

METHODS

This retrospective study included 1734 FET cycles from January 1, 2020, to January 30, 2022. Embryos vitrified using a KITAZATO Vitrification Kit were thawed at 37 °C in all steps (the case group, denoted the "all-37 °C" group) or at 37 °C and then at room temperature (RT; the control group, denoted the "37 °C-RT" group), according to the kit instructions. The groups were matched 1:1 to avoid confounding.

RESULTS

After case-control matching, 366 all-37 °C cycles and 366 37 °C-RT cycles were included. The baseline characteristics were similar (all P > 0.05) between the two groups after matching. FET of the all-37 °C group yielded a higher clinical pregnancy rate (CPR; P = 0.009) and implantation rate (IR; P = 0.019) than FET of the 37 °C-RT group. For blastocyst transfers, the CPR (P = 0.019) and IR (P = 0.025) were significantly higher in the all-37 °C group than in the 37 °C-RT group. For D3-embryo transfers, the CPR and IR were non-significantly higher in the all-37 °C group than in the 37 °C-RT group (P > 0.05).

CONCLUSIONS

Thawing vitrified embryos at 37 °C in all steps with shortening wash time can enhance CPR and IR in FET cycles. Well-designed prospective studies are warranted to further evaluate the efficacy and safety of the all-37 °C thawing method.

Natural cycle frozen embryo transfer: a survey of current assisted reproductive technology practices in the U.S

PURPOSE

Emerging data suggests improved obstetric outcomes with frozen embryo transfer (FET) in an ovulatory or natural cycle (NC-FETs), as compared to programmed endometrial preparation. The objective of this study is to better understand practice patterns and provider attitudes regarding the use of NC-FETs in the United States (U.S.).

METHODS

In this cross-sectional study, an anonymous 22-question survey was emailed to 441 U.S. Assisted Reproductive Technology (ART) clinics to assess the utilization of NC endometrial preparation for FET, protocols used, restrictions to offering NC-FET, and providers' perspectives on advantages and disadvantages of NC-FET. Descriptive statistics were used to analyze survey responses.

RESULT(S)

The survey response rate was 49% (216/441). Seventeen percent of responding clinics did not offer NC-FET. Of the clinics that did not offer NC-FET, 65% had only 1-2 physicians in their practice. Common reasons for not offering NC-FET included "lack of timing predictability for transfer" (81%) and "increased burden on staff/laboratory personnel on holidays and weekends" (54%). Of clinics offering NC-FET, 76% reported < 25% of cycles used the NC for endometrial preparation. Over half (52%) of clinics that offered NC-FET reported having eligibility restrictions for NC-FET. Reported benefits of NC-FET were "patient satisfaction" (18%), "decreased cost of medications" (18%), and "avoidance of intramuscular progesterone" (17%). The attitude towards NC-FET in their clinics was reported as positive by 65% of respondents.

CONCLUSION

NC-FETs are offered by most U.S. ART clinics but are used only in the minority of FET cycles for endometrial preparation, and use is often restricted.

Clinical outcomes of uninterrupted embryo culture with or without time-lapse-based embryo selection versus interrupted standard culture (SelecTIMO): a three-armed, multicentre, double-blind, randomised controlled trial

BACKGROUND

Time-lapse monitoring is increasingly used in fertility laboratories to culture and select embryos for transfer. This method is offered to couples with the promise of improving pregnancy chances, even though there is currently insufficient evidence for superior clinical results. We aimed to evaluate whether a potential improvement by time-lapse monitoring is caused by the time-lapse-based embryo selection method itself or the uninterrupted culture environment that is part of the system.

METHODS

In this three-armed, multicentre, double-blind, randomised controlled trial, couples undergoing in-vitro fertilisation or intracytoplasmic sperm injection were recruited from 15 fertility clinics in the Netherlands and randomly assigned using a web-based, computerised randomisation service to one of three groups. Couples and physicians were masked to treatment group, but embryologists and laboratory technicians could not be. The time-lapse early embryo viability assessment (EEVA; TLE) group received embryo selection based on the EEVA time-lapse selection method and uninterrupted culture. The time-lapse routine (TLR) group received routine embryo selection and uninterrupted culture. The control group received routine embryo selection and interrupted culture. The co-primary endpoints were the cumulative ongoing pregnancy rate within 12 months in all women and the ongoing pregnancy rate after fresh single embryo transfer in a good prognosis population. Analysis was by intention to treat. This trial is registered on the ICTRP Search Portal, NTR5423, and is closed to new participants.

FINDINGS

1731 couples were randomly assigned between June 15, 2017, and March 31, 2020 (577 to the TLE group, 579 to the TLR group, and 575 to the control group). The 12-month cumulative ongoing pregnancy rate did not differ significantly between the three groups: 50·8% (293 of 577) in the TLE group, 50·9% (295 of 579) in the TLR group, and 49·4% (284 of 575) in the control group (p=0·85). The ongoing pregnancy rates after fresh single embryo transfer in a good prognosis population were 38·2% (125 of 327) in the TLE group, 36·8% (119 of 323) in the TLR group, and 37·8% (123 of 325) in the control group (p=0·90). Ten serious adverse events were reported (five TLE, four TLR, and one in the control group), which were not related to study procedures.

INTERPRETATION

Neither time-lapse-based embryo selection using the EEVA test nor uninterrupted culture conditions in a time-lapse incubator improved clinical outcomes compared with routine methods. Widespread application of time-lapse monitoring for fertility treatments with the promise of improved results should be questioned.

FUNDING

Health Care Efficiency Research programme from Netherlands Organisation for Health Research and Development and Merck.

Assisted Reproductive Techniques in Multiple Sclerosis: Recommendations from an Expert Panel

INTRODUCTION

Multiple sclerosis (MS) is mainly diagnosed in women of reproductive age. However, there is a paucity of guidelines jointly prepared by neurologists and gynaecologists on managing women with MS and the desire for motherhood. Therefore, in this review we propose recommendations for such cases, with an particular focus on those requiring assisted reproductive techniques (ART).

METHODS

A group of seven MS experts (4 neurologists and 3 gynaecologists) came together for three discussion sessions to achieve consensus.

RESULTS

The recommendations reported here focus on the importance of early preconception counselling, the management of disease-modifying therapies before and during ART procedures, important considerations for women with MS regarding ART (intrauterine insemination, in vitro fertilisation and oocyte cryopreservation) and the paramount relevance of multidisciplinary units to manage these patients.

CONCLUSIONS

Early preconception consultations are essential to individualising pregnancy management in women with MS, and an early, well-planned, spontaneous pregnancy should be the aim whenever possible. The management of women with MS and the desire for motherhood by multidisciplinary units is warranted to ensure appropriate guidance through the entire pregnancy.

Perinatal outcomes of singletons following double vitrification-warming procedures: a retrospective study using propensity score analysis

BACKGROUND

Although repeated cryopreservation is an occasional occurrence, the effect on perinatal outcomes is unclear. Therefore, the aim of this study was to evaluate the perinatal outcomes of singletons after embryo re-cryopreservation.

METHODS

In this retrospective study, a total of 647 singleton live births after blastocyst freeze-thaw embryo transfer cycles were investigated. They were divided into two groups: vitrified-warmed blastocysts (once-vitrified group) and vitrified-warmed blastocysts derived from thawed cleaved embryos (re-vitrified group). Propensity score matching (PSM) was used to control for potential confounding factors.

RESULTS

A total of 592 infants were included in the once-vitrified group, and 55 infants were included in the re-vitrified group. After PSM, 108 cases were generated for comparison. The median gestational age was 38 weeks for both groups, and the birthweights were comparable (3390.6 ± 601.5 g vs. 3412.8 ± 672.6 g, P > 0.05). The incidence of preterm birth (PTB) (20.4% vs. 16.7%), low birthweight (LBW) (3.7% vs. 7.4%), macrosomia (11.1% vs. 16.7%) and large for gestational age (LGA) (29.6% vs. 22.2%) were not significantly different between the two groups. Logistic regression analysis indicated that double vitrification-warming procedures did not affect the occurrence of PTB (OR, 2.58 [95% CI, 0.77, 8.63]), LBW (OR, 0.83 [95% CI, 0.08, 8.29]), macrosomia (OR, 0.60 [95% CI, 0.13, 2.69]), or LGA (OR, 1.51 [95% CI, 0.53, 4.27]) (P > 0.05, for all).

CONCLUSION

Our findings demonstrate that double vitrification-warming procedures do not increase the risk of adverse neonatal outcomes compared with those of once-vitrified embryos.

Effect of interval between oocyte retrieval and resuscitation embryo transfer on pregnancy outcomes

Objectives

Resuscitation transfer of embryos after elective cryopreservation has been widely applied in in vitro fertilization-embryo transfer (IVF-ET) therapy for human infertility or sterility owing to higher embryo implantation rates. This method separates oocyte retrieval from embryo transfer. The optimal time for frozen embryo transfer (FET) remains unknown. Therefore, this study mainly compares the advantages and disadvantages of delayed FET and immediate FET through retrospective analysis.

Methods

We analyzed real world data of patients who underwent resuscitation transplantation between October 2019 and July 2021 at the Reproductive Center of Chengdu Jinjiang Hospital for Women's and Children's Health. Propensity score matching was applied to control potential confounding factors. A total of 5,549 patients who received at least one FET were analyzed. Patients undergoing transplantation within 60 days of oocyte retrieval were included in the immediate FET group (n = 1,265) and those undergoing transplantation > 60 days after retrieval were included in the delayed FET group (n = 4,284).

Results

Live birth rates between the two groups were comparable (45.25% vs. 45.76%, p = 0.757). Moreover, no difference was observed in the rates of biochemical pregnancy (64.50% vs. 66.80%), clinical pregnancy (55.24% vs. 56.83%), ectopic pregnancy (1.47% vs. 1.39%), early miscarriage (14.41% vs. 16.20%), late miscarriage (2.21% vs. 2.09%), singleton premature delivery (16.67% vs. 18.29%), and neonatal deformity (1.97% vs. 1.80%). After stratifying the patients based on the type of embryo transferred, number of embryos transferred, FET protocol, and good prognosis criteria, live birth rates remained comparable between the two groups (p > 0.05).

Conclusion

Pregnancy outcomes were comparable between the immediate and delayed FET groups.

Impact of Post-Thaw Incubation Time of Frozen Embryos on Clinical Pregnancy Rate

Background

Vitrification of embryos following a single-controlled ovarian stimulation has been the strategy practised now in many in vitro fertilisation clinics to minimise the risk of early ovarian hyper stimulation syndrome, to reduce multiple pregnancy rates and to improve cumulative pregnancy rates. In recent years, advances in vitrification techniques and improved culture conditions have led to good post-thaw embryo survival rates, thereby increasing pregnancy rates of frozen embryo transfer (FET) cycles.

Aim

The aim of this study was to analyse the effect of post-thaw incubation time of frozen embryos on the clinical pregnancy rates (CPRs) of frozen embryo transfer (FET) cycles.

Settings and Design

This was a retrospective, comparative study done at a teaching hospital in assisted reproductive treatment.

Materials and Methods

Three hundred and ten FET cycles were analysed, of which 125 had day 2 freezing and 185 had day 3 freezing. Depending upon the day of thawing and day of transfer, FET cycles were divided into six groups: Group 1 (day 2 thawing and day 3 transfer), Group 2 (day 2 thawing and day 4 transfer), Group 3 (day 2 thawing and day 5 transfer), Group 4 (day 3 thawing and day 3 transfer), Group 5 (day 3 thawing and day 4 transfer) and Group 6 (day 3 thawing and day 5 transfer).

Statistical Analysis Used

Statistical analysis was performed using version 14 R software version 4.0.1 (2020-06-06) (R foundation for Statistical Computing, Vienna, Austria). A P < 0.05 is taken as significant.

Results

The CPR of Group 4 was 42.4% which was more than that of the other groups but it did not reach statistical significance.

Conclusions

Short incubation time of 2-4 h is as effective as an extended incubation time in terms of CPRs of FET cycles.

Evaluation Of The Clinical Results Of Using Microfluidic Channel System For Sperm Selection In IVF Cycles In Patients With Low Sperm Concentration

Objective: Microfluidic channel system (MAC), a new generation method, gives the chance to select better quality spermatozoa with lower DNA fragmentation indices. This study evaluated the treatment results in patients who underwent ICSI-ET due to the MAC technique's male factors. Methods: Sakarya University ART Center carried out this retrospective study. Patients with 35 male factor indications were included in our study. In these patients, swim-up (SU) was used in the first of two consecutive IVF cycles, and the MAC sperm preparation technique was used in the second. Our study compared fertilization, quality embryo counts, implantation after fresh embryo transfer, pregnancy rates, fifth-day embryo, and frozen embryo numbers. Results: Fertilization rate was higher in the MAC group than in the SU group (P=0.009). The number of 3rd and 5th Day Grade 1 embryo in the MAC group was statistically higher than in the SU group (p=0.000 for both parameters). The number of quality embryos frozen on day 5 was higher in the MAC group than in the SU group (P=0.000). Conclusions: It is thought that MAC application does not make a statistically significant contribution on implantation and pregnancy in IVF cycles performed due to the malefactor. However, it may positively affect fertilization rate and embryo quality. In addition, we think that it increases the number of embryos frozen at the end of the cycle, and for this reason, the MAC technique may provide positive benefits to IVF treatments.

Associations of maternal obesity, frozen embryos, and offspring adverse cardiometabolic alterations

OBJECTIVE

To evaluate the long-term cardiometabolic health of offspring conceived by frozen embryo transfer and born to mothers with overweight/obesity.

DESIGN

Retrospective cohort study.

SETTING

Center for Reproductive Medicine.

PATIENT(S)

A total of 2,741 offspring born to mothers who underwent in vitro fertilization/intracytoplasmic sperm injection treatment were followed between June 2014 and August 2021. The offspring were singletons aged 4-11 years at follow-up.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Age-specific z-scores of cardiometabolic parameters were examined, including adiposity, systolic/diastolic blood pressure, glucose, and lipid profiles, and the metabolic sum score of different cardiometabolic characteristics.

RESULTS

Of 2,741 offsprings, 965 (35.21%) were born to mothers with overweight/obesity, including 396 (41.04%) offspring who were conceived by frozen embryo transfer. After adjusting for paternal and maternal age, paternal body mass index (BMI), offspring age, offspring sex, and offspring postnatal energy intake, offspring born to mothers with overweight/obesity and conceived by frozen embryo transfer showed a significantly higher BMI z-score, systolic blood pressure z-score, metabolic sum score-1, and metabolic sum score-2 compared with those conceived by fresh embryo transfer (BMI z-score: adjusted mean difference, 0.17; 95% confidence interval [CI], 0.04-0.30; systolic blood pressure z-score: adjusted mean difference, 0.16; 95% CI, 0.02-0.29; metabolic sum score-1: adjusted mean difference, 0.54; 95% CI, 0.15-0.94; metabolic sum score-2: adjusted mean difference, 0.45; 95% CI, 0.07-0.83). However, in offspring of mothers with normal weight, offspring conceived by frozen embryo transfer showed a significantly lower low-density lipoprotein-cholesterol z-score compared with those conceived by fresh embryo transfer (adjusted mean difference, -0.12; 95% CI, -0.22 to -0.02). Other cardiometabolic parameters were comparable between offspring with frozen and fresh embryo transfers after adjusting for multivariate confounder variables.

CONCLUSIONS

This study found that among offspring from mothers who were overweight/obese, those offspring conceived by frozen embryo transfer were associated with higher systolic blood pressure z-scores and adverse metabolic changes compared with those conceived by fresh embryo transfer. The changes show that the association between frozen embryo transfer and offspring adverse cardiometabolic changes is apparent only among those born to mothers who are overweight/obese.

The impact of embryo vitrification on placental histopathology features and perinatal outcome in singleton live births

STUDY QUESTION

Does embryo vitrification affect placental histopathology pattern and perinatal outcome in singleton live births?

SUMMARY ANSWER

Embryo vitrification has a significant effect on the placental histopathology pattern and is associated with a higher prevalence of dysfunctional labor.

WHAT IS KNOWN ALREADY

Obstetrical and perinatal outcomes differ between live births resulting from fresh and frozen embryo transfers. The effect of embryo vitrification on the placental histopathology features associated with the development of perinatal complications remains unclear.

STUDY DESIGN, SIZE, DURATION

Retrospective cohort study evaluating data of all live births from one academic tertiary hospital resulting from IVF treatment with autologous oocytes during the period from 2009 to 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All patients had placentas sent for pathological evaluation irrelevant of maternal or fetal complications status. Placental, obstetric and perinatal outcomes of pregnancies resulting from hormone replacement vitrified embryo transfers were compared with those after fresh embryo transfers. A multivariate analysis was conducted to adjust the results for determinants potentially associated with the development of placental histopathology abnormalities.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 1014 singleton live births were included in the final analysis and were allocated to the group of pregnancies resulting from fresh (n = 660) and hormone replacement frozen (n = 354) embryo transfers. After the adjustment for confounding factors the frozen embryo transfers were found to be significantly associated with chorioamnionitis with maternal (odds ratio (OR) 2.0; 95% CI 1.2-3.3) and fetal response (OR 2.6; 95% CI 1.2-5.7), fetal vascular malperfusion (OR 3.9; 95% CI 1.4-9.2), furcate cord insertion (OR 2.3 95% CI 1.2-5.3), villitis of unknown etiology (OR 2.1; 95% CI 1.1-4.2), intervillous thrombi (OR 2.1; 95% CI 1.3-3.7), subchorionic thrombi (OR 3.4; 95% CI 1.6-7.0), as well as with failure of labor progress (OR 2.5; 95% CI 1.5-4.2).

LIMITATIONS, REASONS FOR CAUTION

Since the live births resulted from frozen-thawed embryos included treatment cycles with previously failed embryo transfers, the factors over embryo vitrification may affect implantation and placental histopathology.

WIDER IMPLICATIONS OF THE FINDINGS

The study results contribute to the understanding of the perinatal future of fresh and vitrified embryos. Our findings may have an implication for the clinical decision to perform fresh or frozen-thawed embryo transfer.

STUDY FUNDING/COMPETING INTEREST(S)

Authors have not received any funding to support this study. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Strategy for embryo transfer to improve pregnancy outcomes in advanced maternal age

The purpose of this retrospective study was to optimize the transplantation strategy for women of advanced maternal age to achieve live births within the shortest time. Data were collected from patients older than 40 years who underwent assisted reproductive therapy at our centre from 1 January 2009 to 31 December 2019. In total, 1023 cases of fresh cleavage embryo transfer (CET) cycles, 280 cases of frozen-thawed blastocyst transfer (FBT) cycles, and 26 cases of frozen-thawed CET (FCET) cycles were included. The main outcome was the live birth rate (LBR). The secondary outcomes were the clinical pregnancy rate (CPR) and neonatal outcomes. Multivariable logistic regression was performed to adjust for confounding factors. The blastocyst formation rate of patients older than 40 years was 23.5%, the freezing cycle rate was 19.8%, and the fresh-embryo transfer rate was 83.0%. The implantation rate, CPR, and LBR were significantly different among the CET, FCET, and FBT groups. There were no significant differences in multiple pregnancies and abortion rates among the groups, and neonatal outcomes were similar. Multivariate logistic regression analysis showed that, compared with the CET group, LBR did not increase in the FCET group, whereas LBR increased in the FBT group. For patients older than 40 years when having approximately eight embryos after fertilization, blastocyst transfer can be considered after fully discussing the advantages and disadvantages of blastocyst culture. Alternatively, CET can be performed first, followed by FBT if the cleavage embryo transfer is unsuccessful.

Womens’ preferences concerning IVF treatment: a discrete choice experiment with particular focus on embryo transfer policy

STUDY QUESTION

What outcomes are important for women to decide on the day of embryo transfer (ET) in IVF?

SUMMARY ANSWER

The highest cumulative live birth rate (cLBR) per treatment was the most important treatment outcome for women undergoing an IVF treatment, regardless of the number of transfers needed until pregnancy and impact on quality of life.

WHAT IS KNOWN ALREADY

Cleavage stage (Day 3) and blastocyst stage (Day 5) ETs are common transfer policies in IVF. The choice for one or the other day of ET differs between clinics. From the literature, it remains unclear whether the day of transfer impacts the cLBR. Patient preferences for the day of ET have not been examined yet.

STUDY DESIGN, SIZE, AND DURATION

A discrete choice experiment (DCE) was performed to investigate female patients’ preferences and their values concerning various aspects of an IVF treatment, with a particular focus on ET policy. A multicenter DCE was conducted between May 2020 and June 2020 in which participants were asked to choose between different treatments. Each treatment was presented using hypothetical scenarios containing the following attributes: the probability of a healthy live birth per IVF treatment cycle, the number of embryos available for transfer (for fresh and frozen-thawed ET), the number of ETs until pregnancy and the impact of the treatment on the quality of life.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women (n = 445) were asked to participate in the DCE at the start of an IVF treatment cycle in 10 Dutch fertility clinics. Participating women received an online questionnaire. The attributes’ relative importance was analyzed using logistic regression analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 164 women participated. The most important attribute chosen was the cLBR. The total number of embryos suitable for transfer also influenced women’s treatment preferences. Neither the number of transfers needed until pregnancy, nor the impact on quality of life influenced the treatment preferences in the aggregated data. For women in the older age group (age ≥36 years) and the multipara subgroup, the impact on quality of life was more relevant. Naive patients (patients with no prior experience with IVF treatment) assigned less value to the number of ETs needed until pregnancy and assigned more value to the cLBR than the patients who had experienced IVF.

LIMITATIONS REASONS FOR CAUTION

An important limitation of a DCE study is that not all attributes can be included, which might be relevant for making choices. Patients might make other choices in real life as the DCE scenarios presented here are hypothetical and might not exactly represent their personal situation. We tried to avoid potential bias by selecting the attributes that mattered most to the patients obtained through patient focus groups. The final selection of attributes and the assigned levels were established using the input of an expert panel of professionals and by performing a pilot study to test the validity of our questionnaire. Furthermore, because we only included women in our study, we cannot draw any conclusions on preferences for partners.

WIDER IMPLICATIONS OF THE FINDINGS

The results of this study may help fertility patients, clinicians, researchers and policymakers to prioritize the most important attributes in the choice for the day of ET. The present study shows that cLBR per IVF treatment is the most important outcome for women. However, currently, there is insufficient information in the literature to conclude which day of transfer is more effective regarding the cLBR. Randomized controlled trials on the subject of Day 3 versus Day 5 ETs and cLBR are needed to allow evidence-based counseling.

STUDY FUNDING/COMPETING INTEREST(S)

This work received no specific funding and there are no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Predicting clinical pregnancy using clinical features and machine learning algorithms in in vitro fertilization

INTRODUCTION

Assisted reproductive technology has been proposed for women with infertility. Moreover, in vitro fertilization (IVF) cycles are increasing. Factors contributing to successful pregnancy have been widely explored. In this study, we used machine learning algorithms to construct prediction models for clinical pregnancies in IVF.

MATERIALS AND METHODS

A total of 24,730 patients entered IVF and intracytoplasmic sperm injection cycles with clinical pregnancy outcomes at Taipei Medical University Hospital. Data used included patient characteristics and treatment. We used machine learning methods to develop prediction models for clinical pregnancy and explored how each variable affects the outcome of interest using partial dependence plots.

RESULTS

Experimental results showed that the random forest algorithm outperforms logistic regression in terms of areas under the receiver operating characteristics curve. The ovarian stimulation protocol is the most important factor affecting pregnancy outcomes. Long and ultra-long protocols have shown positive effects on clinical pregnancy among all protocols. Furthermore, total frozen and transferred embryos are positive for a clinical pregnancy, but female age and duration of infertility have negative effects on clinical pregnancy.

CONCLUSION

Our findings show the importance of variables and propensity of each variable by random forest algorithm for clinical pregnancy in the assisted reproductive technology cycle. This study provides a ranking of variables affecting clinical pregnancy and explores the effects of each treatment on successful pregnancy. Our study has the potential to help clinicians evaluate the success of IVF in patients.

Predicting the probability of a live birth after a freeze-all based in vitro fertilization-embryo transfer (IVF-ET) treatment strategy

BACKGROUND

The predictors for live birth rate (LBR) following one episode of in vitro fertilization (IVF) cycle for patients using a "freeze-all" strategy are not entirely clear.

METHODS

A retrospective cohort study utilizing a prediction model was developed to assess the relationship to the LBR. Women undergoing IVF with a freeze-all strategy were screened. Univariate models were first fitted for female age at oocytes retrieval/frozen-thawed embryo transfer (FET), body mass index (BMI), duration and etiology of infertility, previous IVF failures, total dose and duration of gonadotrophin, ovarian sensitivity index (OSI), number of oocytes collected, method of fertilization, number of embryos created, number and stage of embryos frozen, type and number of FET cycles, endometrial thickness (EMT)/pattern, hormone level on transplantation day, storage duration, number of embryos thawed and damaged thawed embryos, number and stage of embryos transferred and number of different quality embryos transferred. Variables with P<0.05 in the univariate model were selected for further analysis of the final multivariate discrete-time logistic regression model.

RESULTS

A total of 7,602 women undergoing one ovarian stimulation resulted in 9,964 FETs, of whom 3,066 (40.33%) had a live-birth after their first FET and 3,929 (51.68%) after total FETs. The EMT and woman's age at oocyte retrieval were the most important predictors. In the first FET, the LBR of women with an EMT ≤8 mm [27.40%; 95% confidence interval (CI): (21.60-33.81%)] was significantly lower than that of women with EMT between 9 and 11 mm [36.51%; 95% CI: (34.25-38.81%)] and thicker than 12 mm [44.23%; 95% CI: (42.22-46.25%)] (P<0.05). The optimistic and conservative cumulative LBRs of women younger than 31 years [87.5%; 95% CI: (86.32-88.61%) and 63.04%; 95% CI: (61.36-64.69%)] were significantly decreased in women aged 31-35, 36-40 and >40 (P<0.001).

CONCLUSIONS

Our study provides an effective prediction model for a woman's chance of having a baby after a "freeze-all" policy. The use of EMT and female age as tools to identify LBR are shown to be justified, and repeated FETs cannot reverse the age-dependent decline in fertility.

Effect of post‐warming culture time on the live birth rate after frozen embryo transfer

Purpose

Methods

Results

Conclusions

Facilitators and barriers for home-based monitoring to time frozen embryo transfers in IVF among women and healthcare providers

STUDY QUESTION

What are the facilitators and barriers concerning the implementation of home-based monitoring for natural cycle frozen embryo transfer (NC-FET) from the perspectives of patients and healthcare providers in the Netherlands?

SUMMARY ANSWER

The most important facilitator was optimal pregnancy chance for both the patients and healthcare providers, and the most important barriers were the risk of missing an ovulation for the patients and laboratory capacity for the healthcare providers.

WHAT IS KNOWN ALREADY

The share of FET cycles in IVF treatments is increasing and, therefore, it is important to optimize protocols for FET. Monitoring of ovulation, which is used in NC-FET, can be hospital-based (ultrasounds and ovulation triggering) or home-based (LH urine tests). Home-based monitoring has the advantage of being the most natural protocol for FET and provides the feeling of empowerment and discretion for patients. A systematic approach for the implementation of home-based monitoring has to start with an exploration of the perspectives of all stakeholders.

STUDY DESIGN SIZE DURATION

Stakeholders (patients and healthcare providers) involved in the implementation process in the Netherlands participated in the present study. Patients were represented by the Dutch Patient Organisation for Couples with Fertility Problems (FREYA) and healthcare providers were represented by gynaecologists and their society (The Netherlands Society of Obstetrics and Gynaecology), embryologists and their society (The Dutch Federation of Clinical Embryology) as well as fertility doctors. A panel of experts hypothesized on barriers and facilitators for the implementation of home-based monitoring during the proposal phase of the Antarctica-2 randomized controlled trial (RCT).

PARTICIPANTS/MATERIALS SETTING METHODS

All stakeholders were represented during the study. Two different questionnaires were developed in order to investigate facilitators and barriers for the patients and for healthcare providers. The facilitators and barriers were ranked on a scale of 1-10 with 10 being the most important. Based on our power analysis, we aimed for a minimum of 300 completed questionnaires for the patients and a minimum of 90 completed questionnaires for the healthcare providers. Facilitators and barriers were analysed using frequencies, mean (SD) and ranking.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 311 patients filled out the questionnaire of whom 86.8% underwent FET previously. The most important facilitator for the patients was to implement the strategy with the highest chance of pregnancy (mean 9.7; 95% CI 9.6-9.7) and the most important barrier was risk of missing ovulation (mean 8.4; 95% CI 8.2-8.6). A total of 96 healthcare providers filled out the questionnaire. According to healthcare providers, patients would accept the strategy when it causes less interference with their work and private life (mean 7.5; 95% CI 7.1-8.0) and has a low risk of missing the ovulation (mean 7.6; 95% CI 7.1-8.0). The most important facilitator for the implementation of home-based monitoring for healthcare providers was optimizing cumulative pregnancy rates (mean 8.1; 95% CI 7.7-8.4) and the most important barrier was the lack of laboratory capacity and flexibility (mean 6.4; 95% CI 5.8-7.0).

LIMITATIONS REASONS FOR CAUTION

Facilitators and barriers were selected based on expert opinion. Currently, there are no validated questionnaires that aim to assess facilitators and barriers for the implementation of treatments in fertility care.

WIDER IMPLICATIONS OF THE FINDINGS

During our study, we gained insight into barriers and facilitators for the implementation of home-based monitoring of NC-FET at an early phase. Early sharing and discussion of the results of this study with all stakeholders involved should stimulate a fast incorporation in guidelines, especially as key professionals in guideline development took part in this study. Also, based on our results, we can advise guideline developers to add tools to the guideline that may help overcome the implementation barriers.

STUDY FUNDING/COMPETING INTERESTS

The Antarctica-2 RCT is supported by a grant from the Netherlands Organisation for Health Research and Development (ZonMw 843002807). No authors have any competing interests to declare.

TRIAL REGISTRATION NUMBER

Trial NL6414 (NTR6590).

The impact of blastomere loss on pregnancy and neonatal outcomes of vitrified-warmed Day3 embryos in single embryo transfer cycles

BACKGROUND

Blastomere loss is a common phenomenon that occurs following cryopreservation. To date, studies have drawn conflicting conclusions regarding the impact of blastomere loss on pregnancy outcomes. Besides, limited information is available concerning the neonatal safety of embryos with blastomere loss. In the present study, we aimed to investigate the impact of blastomere loss on pregnancy and neonatal outcomes of vitrified/warmed Day3 cleavage-stage embryos in single embryo transfer cycles.

METHODS

This retrospective cohort study included all vitrified/warmed D3 cleavage-stage single frozen-thawed embryo transfer (FET) cycles between April 2015 and February 2021. We compared pregnancy and subsequent neonatal outcomes between the intact embryos group and the blastomere loss group in single FET cycles.

RESULTS

A total of 6287 single FET cycles were included in the study, in which 5873 cycles were classified into the intact embryo group and 414 cycles were classified into the blastomere loss group. The outcomes of the blastomere loss group were significantly inferior to those of the intact embryo group, in terms of implantation/biochemical pregnancy/clinical pregnancy/ongoing pregnancy rate and live birth rate per embryo transfer cycle/per clinical pregnancy. Further binary logistic regression confirmed that blastomere loss was negatively associated with live birth. Moreover, the blastomere loss group presented with an elevated early miscarriage rate. The neonatal conditions were broadly similar between the two groups. Additionally, multiple binary logistic regression analysis demonstrated that primary infertility and intracytoplasmic sperm injection (ICSI) were common influencing factors of blastomere loss (aOR 1.447, 95% CI 1.038-2.019, P = 0.029; aOR: 1.388, 95% CI: 1.044-51.846, P = 0.024).

CONCLUSIONS

The transfer of vitrified/warmed D3 embryos with blastomere loss is related to impaired embryo developmental potentials and reduced probabilities of conception. Moreover, even if the embryos with blastomere loss have implanted and reached clinical pregnancies, they present with a lower possibility of developing to live birth owing to a higher early miscarriage rate. However, once the embryos with blastomere loss result in a live birth, no adverse neonatal outcomes are observed. Primary infertility and ICSI were found to be risk factors for blastomere loss.

Treatment outcomes of blastocysts thaw cycles, comparing the presence and absence of a corpus luteum: a systematic review and meta-analysis

PURPOSE

This study aims to review the literature and perform a meta-analysis to determine if the presence of a corpus luteum has an impact on treatment outcomes in thaw cycles, where blastocyst embryos are transferred.

METHOD

PUBMED, EMBASE, CENTRAL and CINAHL were searched for papers published between January 2017 and 27 July 2020. Additional articles were selected from the reference list of the results and previous reviews. Three reviewers independently reviewed and extracted data. The meta-analysis was conducted though RevMan V.5.4.1. Studies were quality assessed with the Cochrane risk of bias tool and the Newcastle-Ottawa Scale.

RESULTS

Nine publications were included for data extraction and subsequent meta-analysis. Two studies were randomised controlled trials, and seven were cohort studies. Subgroup analysis of the different study designs was performed. While the rates of positive human chorionic gonadotropin results (relative risk, RR 1.0, 95% CI 0.95 to 1.05) and clinical pregnancies (RR 1.06, 95% CI 0.96 to 1.18) were comparable between the two groups, the rates of live births were higher in thaw cycles with a corpus luteum (RR 1.14, 95% CI 1.06 to 1.22). Analysis of pregnancy losses demonstrated that both biochemical pregnancy (early miscarriage) (RR 0.71, 95% CI 0.62 to 0.82) and miscarriages (RR 0.72, 95% CI 0.62 to 0.83) were increased in cycles without a corpus luteum.

CONCLUSION

Where clinically appropriate, the use of cycle types that have a functional corpus luteum should be favoured. There were several limitations to this study, including the quality of studies and the inherent bias of retrospective cohort studies. Further, high-quality research, particularly randomised controlled trials with blastocysts embryos, is required to further explore these findings.

PROSPERO REGISTRATION NUMBER

CRD42020209583.

Clinical outcomes after elective double-embryo transfer in frozen cycles for women of advanced maternal age: A retrospective cohort study

We aimed to determine the clinical outcome of double cleavage-stage embryo transfers in frozen-thawed embryo transfer cycles for older women.This study analyzed a total of 8189 cleavage-stage frozen-thawed embryo transfer cycles between January 2013 and December 2017 at Sir Run Run Shaw Hospital. All cycles were sorted into 3 groups based on patient age: ≤35 years (Group A), 36 to 37 years (Group B), and ≥38 years (Group C). The clinical pregnancy rate (CPR), implantation rate (IR), live birth rate (LBR), miscarriage rate, multiple pregnancy rate (MPR), preterm birth rate, and low-birth-weight rate were compared between the 3 groups.Significant differences in CPR, IR, LBR, MPR, and premature birth rate were found among the 3 groups. The CPR, IR, LBR, and MPR in Group A were higher than those in Group C. Transfers of 2 high-quality embryos resulted in significant differences in CPR, IR, LBR, MPR, and neonatal weight among the 3 groups, but no differences in premature birth and abortion rates were observed. Transfers with 1 high-quality and 1 fair-quality embryo resulted in significant differences in CPR, IR, and LBR among the 3 groups. Comparison of transfers of 2 high-quality embryos with 1 high-quality and 1 fair-quality embryo showed that the CPR and LBR were significantly lower for the latter in Groups A and C, but Group B had no salient changes.Higher IR and LBR and lower MPR may be achieved by selection of optimal embryo types for patients of different ages. Two high-quality embryos need to be transferred in women older than 38 years. For women aged 36 to 37 years, 1 high-quality embryo or 1 high-quality plus 1 fair-quality embryo should be singled out for transfer. For women younger than 35 years, a single high-quality embryo should be selected for transfer.

The impact of endometrial preparation for frozen embryo transfer on maternal and neonatal outcomes: a review

The use of frozen embryo transfer in assisted reproductive technology (ART) has steadily increased since development in the early 1980's. While there are many benefits to delayed frozen embryo transfer, certain adverse perinatal outcomes are noted to be more common in these transfers when compared to fresh transfers, specifically hypertensive disorders of pregnancy. Frozen embryo transfers require coordination between the embryo's developmental stage and the endometrial environment and can occur in either ovulatory or programmed cycles. Though there is no consensus on the ideal method of endometrial preparation prior to frozen embryo transfer, emerging data suggests differences in maternal and neonatal outcomes, specifically increased rates of hypertensive disorders of pregnancy in programmed cycles. Other reported differences include an increased risk of cesarean delivery, placenta accreta, postpartum hemorrhage, low birthweight, preterm birth, post term delivery, macrosomia, large for gestational age, and premature rupture of membranes in programmed cycles. The mechanism by which these differences exist could reflect inherent differences in groups selected for each type of endometrial preparation, the role of super physiologic hormone environments in programmed cycles, or the unique contributions of the corpus luteum in ovulatory cycles that are not present in programmed cycles. Given that existing studies are largely retrospective and have several key limitations, further investigation is needed. Confirmation of these findings has implications for current practice patterns and could enhance understanding of the mechanisms behind important adverse perinatal outcomes in those pursuing assisted reproduction.

Frozen Blastocyst Embryo Transfer: Comparison of Protocols and Factors Influencing Outcome

Background: Various factors, including treatment protocols, can influence the outcomes of frozen embryo transfers (FETs). The study objectives were to compare different endometrial preparation protocols of FET cycles and to evaluate the factors, including the endometrial thickness (ET), that affect outcomes. Methods: This observational cohort study involved 5037 women undergoing FETs at eight tertiary clinics in the UK between January 2016 and March 2019. The endometrial preparation protocols used were natural cycle (NC-FETs), artificial hormone support cycle with oestradiol valerate but without pituitary downregulation (AC-FETs) and artificial hormone support cycle with agonist downregulation (ACDR-FETs). Results: The mean (±SD) ages across NC-FET, AC-FET and ACDR-FET groups were 36.5 (±4.2), 35.9 (±5.0) and 36.4(±4.9) years, respectively. LBRs were comparable (40.7%, 175/430; 36.8%, 986/2658; and 36.7%, 716/1949, respectively) across the three groups. Clinical pregnancy, implantation, multiple pregnancies, miscarriage and ectopic pregnancy rates were also similar. In the regression analysis of variables including age, duration of infertility, number of embryos transferred, protocol type and endometrial thickness, age was the only significant predictor of LBRs, although its predictive ability was poor (AUC: 0.55). With the overall LBR of the study population being 37.1%, the post-test probability of a live birth at an ET of <5 mm was 0%, and at 5–5.9, 6–6.9, 7–7.9 and 8–8.9 mm, the probabilities were 16.7%, 33.8%, 36.7% and 37.7%, respectively. The LBR remained above 35% up to the 14–14.9 mm range and then declined gradually to 23% for the 17–25 mm range. Conclusions: The FET outcomes were similar for the three protocols used for endometrial preparation. The protocol type and endometrial thickness were not predictive of FET outcomes; age was the only predictive variable, despite its low predictive ability.

Melatonin Improves Quality of Repeated-Poor and Frozen-Thawed Embryos in Human, a Prospective Clinical Trial

OBJECTIVE

In this study, two experiments were performed to assess the effect and the role of melatonin on human in vitro embryo quality.

METHODS

Experiment I: A total of 42 repeated-poor-quality-embryo patients were enrolled, with a total of 181 oocytes retrieval cycles. After IVF, for the same patient, the MT cycles group (10^-7 M melatonin added to the culture medium; n=48) were compared with the previous non-MT cycles group (n=133), following by in vitro culture to blastocyst stage and embryo transfer. 31 patients were transplanted with 65 embryo transfer, including 24 MT embryo transfer, 41 non-MT embryo transfer. Cycle outcomes were compared between the two groups. Experiment II:A total of 143 supernumerary human cleavage-stage embryos (from non-repeated-poor-quality-embryo patients) vitrified on Day 3 after IVF were warmed and randomized into two groups: melatonin group (10^-7 M melatonin added to the culture medium; n=71) and control group (n=72), and then cultured for 72 h. Rate of blastocyst and high-quality blastocyst, reactive oxygen species (ROS) levels of culture media as well as embryonic GPX1, CAT, Mn-SOD, Cu/Zn-SOD, BCL-2, BAX gene expression levels were analyzed.

RESULTS

Experiment I: Results showed that the rate of Day 3 high-quality embryos (29.6% vs.19.5%) in the MT cycles group was significantly higher than that in the non-MT cycles group (P<0.05). The rate of available blastocysts (17.1% vs.12.7%) and clinical pregnancy rate (25.0% vs.17.1%) were in tendency higher in the group treated with melatonin (P>0.05). Experiment II:Results showed that the blastocyst rates in the melatonin administered group were significantly higher than in control group (42.25% vs.26.38%, P<0.05). There were no significant differences in high-quality blastocyst rates. In addition, quantitative PCR showed that the expression of CAT was significantly upregulated by melatonin treatment (P<0.05), while there were no significant differences in the expression of GPX1, Mn-SOD, Cu/Zn-SOD, BAX and BCL-2 gene as well as the levels of ROS.

CONCLUSION

These data showed that melatonin supplement in the culture medium will improve Day 3 high-quality embryos rate of repeated-poor-quality-embryo patients and improve blastocyst rate of vitrified-warmed cleavage-stage embryos, suggesting that melatonin intervention may provide a potential rescue strategy for IVF failures.

CLINICAL TRIAL REGISTRATION

identifier [ChiCTR2200059773].

Adolescent Fertility Preservation: Where Do We Stand Now

Adolescence is a period of flux for many body systems. While fertility potential typically increases after menarche, there are diseases where the opposite occurs and fertility preservation options need to be considered early. In cases of cancer, options vary by pubertal status and can include ovarian tissue cryopreservation, oocyte cryopreservation, sperm cryopreservation, and testicular tissue cryopreservation. Much remains to be learned about fertility and preservation options in those with differences in sexual development (DSDs); however, depending on the form of DSD, fertility preservation may not be necessary. Similarly, traditional fertility counseling in children with galactosemia may need to be changed, as data suggest that fertility rates attributed to other causes of premature ovarian insufficiency may not be as applicable to this disease. Adolescents with Turner's syndrome are at high risk for premature ovarian failure; therefore, it is important to consider options as early as possible since ovarian reserves are depleted quickly. On the other hand, transgender and gender diverse adolescents may even be able to undergo fertility preservation after starting hormone therapy. In all cases, there are additional ethical components including technical/surgical risks in childhood, offering experimental therapies without creating false hope and evaluating children's consent and assent capabilities that must be considered.

Cryopreservation of Gametes and Embryos and Their Molecular Changes

The process of freezing cells or tissues and depositing them in liquid nitrogen at -196 °C is called cryopreservation. Sub-zero temperature is not a physiological condition for cells and water ice crystals represent the main problem since they induce cell death, principally in large cells like oocytes, which have a meiotic spindle that degenerates during this process. Significantly, cryopreservation represents an option for fertility preservation in patients who develop gonadal failure for any condition and those who want to freeze their germ cells for later use. The possibility of freezing sperm, oocytes, and embryos has been available for a long time, and in 1983 the first birth with thawed oocytes was achieved. From the mid-2000s forward, the use of egg vitrification through intracytoplasmic sperm injection has improved pregnancy rates. Births using assisted reproductive technologies (ART) have some adverse conditions and events. These risks could be associated with ART procedures or related to infertility. Cryopreservation generates changes in the epigenome of gametes and embryos, given that ART occurs when the epigenome is most vulnerable. Furthermore, cryoprotective agents induce alterations in the integrity of germ cells and embryos. Notably, cryopreservation extensively affects cell viability, generates proteomic profile changes, compromises crucial cellular functions, and alters sperm motility. This technique has been widely employed since the 1980s and there is a lack of knowledge about molecular changes. The emerging view is that molecular changes are associated with cryopreservation, affecting metabolism, cytoarchitecture, calcium homeostasis, epigenetic state, and cell survival, which compromise the fertilization in ART.

Single blastocyst stage versus single cleavage stage embryo transfer following fresh transfer: A systematic review and meta-analysis

OBJECTIVES

To compare the available evidence of the effectiveness of single blastocyst stage transfer against the effectiveness of single cleavage stage embryo transfer.

STUDY DESIGN

A systematic research based on Pubmed, Embase and the Cochrane Library was performed until May 2, 2020 to identify all relevant studies. The Cochrane Collaboration's Review Manager (RevMan) 5.0.2 software was used for statistical analysis.

RESULTS

Five randomized controlled trials (RCTs) were included in analysis, involving 1784 patients in total, who were divided into 2 groups, which were the single blastocyst stage transfer (SBT) group of 932, and the single cleavage stage transfer (SCT) group of 852. Our meta-analysis concluded that SBT group had a significantly higher clinical pregnancy rate (RR 1.26; 95%CI: 1.14-1.39), ongoing pregnancy rate (RR 1.19; 95%CI: 1.05-1.35) and delivery rate (RR 1.4; 95%CI: 1.13-1.75) than SCT group during the fresh transfer. While miscarriage rate (RR 0.93; 95% CI: 0.66-1.33), multiple pregnancy rate (RR, 1.12; 95% CI, 0.51-2.45) and ectopic pregnancy rate (RR, 0.5; 95% CI: 0.13-1.90) between two groups showed no significant difference. However, the SCT group contained notably more cryopreserved embryos than the SBT group. (RR -0.68, 95% CI: -0.95 to -0.41).

CONCLUSIONS

Our results indicate that single blastocyst stage transfer is associated with higher ongoing pregnancy rate and delivery rate comparing to single cleavage stage transfer in the clinical practice. Due to the low quality of the evidence of the primary outcomes, other higher-quality lager RCTs are necessary before a fully informed decision is made.

Is home-based monitoring of ovulation to time frozen embryo transfer a cost-effective alternative for hospital-based monitoring of ovulation? Study protocol of the multicentre, non-inferiority Antarctica-2 randomised controlled trial

STUDY QUESTION

The objective of this trial is to compare the effectiveness and costs of true natural cycle (true NC-) frozen embryo transfer (FET) using urinary LH tests to modified NC-FET using repeated ultrasound monitoring and ovulation trigger to time FET in the NC. Secondary outcomes are the cancellation rates of FET (ovulation before hCG or no dominant follicle, no ovulation by LH urine test, poor embryo survival), pregnancy outcomes (miscarriage rate, clinical pregnancy rates, multiple ongoing pregnancy rates, live birth rates, costs) and neonatal outcomes (including gestational age, birthweight and sex, congenital abnormalities or diseases of babies born).

WHAT IS KNOWN ALREADY

FET is at the heart of modern IVF. To allow implantation of the thawed embryo, the endometrium must be prepared either by exogenous oestrogen and progesterone supplementation (artificial cycle (AC)-FET) or by using the NC to produce endogenous oestradiol before and progesterone after ovulation to time the transfer of the thawed embryo (NC-FET). During an NC-FET, women visit the hospital repeatedly and receive an ovulation trigger to time FET (i.e. modified (m)NC-FET or hospital-based monitoring). From the woman's point of view, a more natural approach using home-based monitoring of the ovulation with LH urine tests to allow a natural ovulation to time FET may be desired (true NC-FET or home-based monitoring).

STUDY DESIGN SIZE DURATION

This is a multicentre, non-inferiority prospective randomised controlled trial design. Consenting women will undergo one FET cycle using either true NC-FET or mNC-FET based on randomisation.

PARTICIPANTS/MATERIALS SETTING METHODS

Based on our sample size calculation, the study group will consist of 1464 women between 18 and 45 years old who are scheduled for FET. Women with anovulatory cycles, women who need ovulation induction and women with a contra indication for pregnancy will be excluded. The primary outcome is ongoing pregnancy. Secondary outcomes are cancellation rates of FET, pregnancy outcomes (including miscarriage rate, clinical pregnancy, multiple pregnancy rate and live birth rate). Costs will be estimated by counting resource use and calculating unit prices.

STUDY FUNDING/COMPETING INTERESTS

The study received a grant from the Dutch Organisation for Health Research and Development (ZonMw 843002807; www.zonmw.nl). ZonMw has no role in the design of the study, collection, analysis, and interpretation of data or writing of the manuscript. F.B. reports personal fees from member of the external advisory board for Merck Serono, grants from Research support grant Merck Serono, outside the submitted work. A.E.P.C. reports and Unrestricted grant of Ferring B.V. to the Center for Reproductive medicine, no personal fee. Author up-to-date on Hyperthecosis. Congress meetings 2019 with Ferring B.V. and Theramex B.V. M.G. reports Department research and educational grants from Guerbet, Merck and Ferring (location VUMC) outside the submitted work. E.R.G. reports personal fees from Titus Health Care, outside the submitted work. C.B.L. reports grants from Ferring, grants from Merck, from Guerbet, outside the submitted work. The other authors have none to declare.

TRIAL REGISTRATION NUMBER

Dutch Trial Register (Trial NL6414 (NTR6590), https://www.trialregister.nl/).

TRIAL REGISTRATION DATE

23 July 2017.

DATE OF FIRST PATIENT’S ENROLMENT

10 April 2018.

Immediate versus delayed frozen embryo transfer in women following a failed IVF-ET attempt: a multicenter randomized controlled trial

BACKGROUND

The optimal time at which to perform a frozen-thawed embryo transfer (FET) following a failed in-vitro fertilization-embryo transfer (IVF-ET) attempt remains elusive to most reproductive experts. Physicians often delay the introduction of FET due to concerns related to potential residual effects of ovarian hyperstimulation which may interfere with the regular menstrual cycle. Moreover, given that most of the published studies on the topic are retrospective and have inconsistent findings, it is crucial to develop evidence-based randomized control guides for clinical practice. Therefore, this well-designed randomized controlled trial (RCT) was conducted to determine whether it is necessary to delay FET for at least one menstrual cycle after the failure of fresh embryo transfer.

METHODS

Infertile women eligible for IVF-ET were invited to participate in this multicenter, randomized, non-inferiority, parallel-group, unblinded, controlled trial at the academic fertility centers of four public hospitals in Chinese Mainland. Infertile women scheduled to receive their first FET cycle after a failed IVF-ET attempt were randomly assigned to either (a) the immediate FET group in which FET was performed in the first menstrual cycle following the failed IVF-ET cycle (n = 366) or (b) the delayed FET group in which FET was performed in the second or subsequent menstrual cycle following the failed IVF-ET cycle (n = 366). All FET cycles were performed during hormone replacement cycles for endometrial preparation. The primary outcome was the ongoing pregnancy, defined as a detectable fetal heart beat beyond twelve weeks of gestation. Secondary outcomes were other pregnancy-related outcomes, maternal and neonatal complications. Analysis was performed by both intention-to-treat and per-protocol principles.

RESULTS

A total of 646 FETs were completed. The frequency of moderate to severe depression and high stress level prior to FET in delayed FET group were significantly higher than that in immediate FET group (10.6% vs 6.1%, p = 0.039; 30.3% vs 22.4%, p = 0.022, respectively). Immediate FET resulted in a higher frequency of clinical pregnancy than did delayed FET (41.7% vs 34.1%), for a relative risk (RR) of 1.23 (95% confidence interval [CI], 1.00-1.50; p = 0.045). Women who underwent immediate FET also had a lower frequency of biochemical pregnancy loss (11.7% vs. 30.6%), with a RR of 0.28 (95% CI 0.23-0.63, p < 0.001), and a higher frequency of embryo implantation (25.2% vs. 20.2%), with a RR of 1.25 (95% CI 1.01-1.53; p = 0.038). Although the ongoing pregnancy and live birth rates did not differ significantly between the immediate FET and delayed FET groups (37.1% vs 30.3%, RR 1.22, 95% CI 0.99-1.52, p = 0.067; 36.5% vs 30.0%, RR 1.22, 95% CI 0.98-1.52, p = 0.079, respectively), a multivariate logistic regression analysis adjusted for potential confounders such as depression and stress levels revealed that the immediate FET group had a significantly higher ongoing pregnancy and live birth rates than the delayed FET group (odds ratio 0.68, 95% CI 0.47-0.99, p = 0.041; odds ratio 0.67, 95% CI 0.46-0.96, p = 0.031). The risks of maternal and neonatal complications were comparable between the two groups.

CONCLUSIONS

In women with a previous failed IVF-ET attempt, immediate FET resulted in higher ongoing pregnancy and live birth rates than delayed FET. These findings warrant caution in the indiscriminate application of a delayed FET strategy when apparent risk of high stress level is perceived.

TRIAL REGISTRATION

ChiCTR2000033313 .

High serum anti-Müllerian hormone concentrations have a negative impact on fertilization and embryo development rates

RESEARCH QUESTION

What is the impact of high serum anti-Müllerian hormone (AMH) concentrations on fertilization and embryo development among infertile women undergoing treatment with assisted reproductive technology (ART)?

DESIGN

Retrospective study of 1036 infertile women undergoing ART; women were divided into three groups according to serum AMH concentrations: AMH <1.1 ng/ml, 1.1-5.0 ng/ml and >5.0 ng/ml. The fertilization and embryo development rates of patients with different AMH concentrations and after stratification according to age were compared.

RESULTS

Women with high AMH concentrations were younger and had higher testosterone concentrations (0.4 ± 0.13 versus 0.3 ± 0.12 versus 0.3 ± 0.08 µg/dl, P < 0.001) than women with low AMH concentrations. However, analysis of the embryo development rate showed negative outcomes for women with high AMH concentrations, including a poor fertilization rate (76.3 ± 17.36 versus 82.1 ± 19.15 versus 82.4 ± 25.38, P = 0.003), and poor day 3 embryo development rate (55.6 ± 23.88 versus 62.6 ± 26.52 versus 62.8 ± 32.65, P = 0.014). Multivariate linear regression analysis showed significantly negative correlations of the AMH concentrations with the fertilization rate (P < 0.001) and day 3 embryo development rate (P = 0.006). Subgroup analysis showed that age 30 years or younger had a significant negative correlation with AMH and the embryo development rate, including the fertilization rate (P < 0.001) and day 3 embryo development rate (P = 0.037).

CONCLUSION

These results suggest that high serum AMH concentrations, contributing to a hyperandrogenic environment and leading to decreased oocyte developmental competence, may have a negative impact on fertilization and the early stage of embryo development in women undergoing treatment with ART.

Post-warming survival rates and clinical outcomes of human cleavage stage embryos vitrified/warmed using CryoTouch and Cryotop methods

Background

Vitrification has become the method of choice for cryopreservation of human embryos and gametes. There are multiple commercial media, containing different combinations and concentrations of cryoprotectants, available for vitrification and warming procedures. The aim of this retrospective study was to compare post-warming survival rate and clinical outcomes of cleavage stage embryos vitrified/warmed using two different commercial methods (CryoTouch and Cryotop) during intracytoplasmic sperm injection/frozen embryo transfer (ICSI/FET) cycles. This retrospective study evaluated a total of 173 FET cycles performed on 446 warmed cleavage stage embryos between January 2018 and December 2020. Post-warming embryo survival rate and clinical outcomes including clinical pregnancy, implantation, and live birth rates were calculated.

Results

The results showed no significant differences between two groups in terms of post-warming survival rate (p value = 0.5020), clinical pregnancy rate (p value = 0.7411), implantation rate (p value = 0.4694), and live birth rate (p value = 0.5737).

Conclusions

Collectively, high successful rates were observed in outcomes of vitrified/warmed cleavage stage embryos using both CryoTouch and Cryotop commercial methods.

Immediate versus delayed frozen embryo transfer in patients following a stimulated IVF cycle: a randomised controlled trial

STUDY QUESTION

Is there any difference in the ongoing pregnancy rate after immediate versus delayed frozen embryo transfer (FET) following a stimulated IVF cycle?

SUMMARY ANSWER

Immediate FET following a stimulated IVF cycle produced significantly higher ongoing pregnancy and live birth rate than did delayed FET.

WHAT IS KNOWN ALREADY

Embryo cryopreservation is an increasingly important part of IVF, but there is still no good evidence to advise when to perform FET following a stimulated IVF cycle. All published studies are retrospective, and the findings are contradictory.

STUDY DESIGN, SIZE, DURATION

This was a randomised controlled non-inferiority trial of 724 infertile women carried out in two fertility centres in China between 9 August 2017 and 5 December 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Infertile women having their first FET cycle after a stimulated IVF cycle were randomly assigned to either (1) the immediate group in which FET was performed in the first menstrual cycle following the stimulated IVF cycle (n = 362) or (2) the delayed group in which FET was performed in the second or later menstrual cycle following the stimulated IVF cycle (n = 362). All FET cycles were performed in hormone replacement cycles. The randomisation sequence was generated using an online randomisation program with block sizes of four. The primary outcome was the ongoing pregnancy rate, defined as a viable pregnancy beyond 12 weeks of gestation. The non-inferiority margin was -10%. Analysis was performed by both per-protocol and intention-to-treat approaches.

MAIN RESULTS AND THE ROLE OF CHANCE

Women in the immediate group were slightly younger than those in the delayed group (30.0 (27.7-33.5) versus 31.0 (28.5-34.2), respectively, P = 0.006), but the proportion of women ≤35 years was comparable between the two groups (308/362, 85.1% in the immediate group versus 303/362, 83.7% in the delayed group). The ongoing pregnancy rate was 49.6% (171/345) in the immediate group and 41.5% (142/342) in the delayed group (odds ratios 0.72, 95% CI 0.53-0.98, P = 0.034). The live birth rate was 47.2% (163/345) in the immediate group and 37.7% (129/342) in the delayed group (odds ratios 0.68, 95% CI 0.50-0.92, P = 0.012). The miscarriage rate was 13.2% (26 of 197 women) in the immediate group and 24.2% (43 of 178 women) in the delayed group (odds ratios 2.10; 95% CI 1.23-3.58, P = 0.006). The multivariable logistic regression, which adjusted for potential confounding factors including maternal age, number of oocytes retrieved, embryo stage at transfer, number of transferred embryos/blastocysts, reasons for FET, ovarian stimulation protocol and trigger type, demonstrated that the ongoing pregnancy rate was still higher in the immediate group.

LIMITATIONS, REASON FOR CAUTION

Despite randomisation, the two groups still differed slightly in the age of the women at IVF. The study was powered to consider the ongoing pregnancy rate, but the live birth rate may be of greater clinical interest. Conclusions relating to the observed differences between the treatment groups in terms of live birth rate should, therefore, be made with caution.

WIDER IMPLICATIONS OF THE FINDINGS

Immediate FET following a stimulated IVF cycle had a significantly higher ongoing pregnancy and live birth rate than delayed FET. The findings of this study support immediate FET after a stimulated IVF cycle.

STUDY FUNDING/COMPETING INTEREST(S)

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

TRIAL REGISTRATION NUMBER

ClinicalTials.gov identifier: NCT03201783.

TRIAL REGISTRATION DATE

28 June 2017.

DATE OF FIRST PATIENT’S ENROLMENT

9 August 2017.

Transfer of fresh or frozen embryos: a randomised controlled trial

STUDY QUESTION

Is IVF with frozen-thawed blastocyst transfer (freeze-all strategy) more effective than IVF with fresh and frozen-thawed blastocyst transfer (conventional strategy)?

SUMMARY ANSWER

The freeze-all strategy was inferior to the conventional strategy in terms of cumulative ongoing pregnancy rate per woman.

WHAT IS KNOWN ALREADY

IVF without transfer of fresh embryos, thus with frozen-thawed embryo transfer only (freeze-all strategy), is increasingly being used in clinical practice because of a presumed benefit. It is still unknown whether this new IVF strategy increases IVF efficacy.

STUDY DESIGN, SIZE, DURATION

A single-centre, open label, two arm, parallel group, randomised controlled superiority trial was conducted. The trial was conducted between January 2013 and July 2015 in the Netherlands. The intervention was one IVF cycle with frozen-thawed blastocyst transfer(s) versus one IVF cycle with fresh and frozen-thawed blastocyst transfer(s). The primary outcome was cumulative ongoing pregnancy resulting from one IVF cycle within 12 months after randomisation. Couples were allocated in a 1:1 ratio to the freeze-all strategy or the conventional strategy with an online randomisation programme just before the start of down-regulation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were subfertile couples with any indication for IVF undergoing their first IVF cycle, with a female age between 18 and 43 years. Differences in cumulative ongoing pregnancy rates were expressed as relative risks (RR) with 95% CI. All outcomes were analysed following the intention-to-treat principle.

MAIN RESULTS AND THE ROLE OF CHANCE

Two-hundred-and-five couples were randomly assigned to the freeze-all strategy (n = 102) or to the conventional strategy (n = 102). The cumulative ongoing pregnancy rate per woman was significantly lower in women allocated to the freeze-all strategy (19/102 (19%)) compared to women allocated to the conventional strategy (32/102 (31%); RR 0.59; 95% CI 0.36-0.98).

LIMITATIONS, REASONS FOR CAUTION

As this was a single-centre study, we were unable to study differences in study protocols and clinic performance. This, and the limited sample size, should make one cautious in using the results as the basis for definitive policy. All patients undergoing IVF, including those with a poor prognosis, were included; therefore, the outcome could differ in women with a good prognosis of IVF treatment success.

WIDER IMPLICATIONS OF THE FINDINGS

Our results indicate that there might be no benefit of a freeze-all strategy in terms of cumulative ongoing pregnancy rates. The efficacy of the freeze-all strategy in subgroups of patients, different stages of embryo development, and different freezing protocols needs to be further established and balanced against potential benefits and harms for mothers and children.

STUDY FUNDING/COMPETING INTEREST(S)

The Netherlands Organisation for Health Research and Development (ZonMW grant 171101007). S.M., F.M. and M.v.W. stated they are authors of the Cochrane review 'Fresh versus frozen embryo transfers in assisted reproduction'.

TRIAL REGISTRATION NUMBER

Dutch Trial Register, NTR3187.

TRIAL REGISTRATION DATE

9 December 2011.

DATE OF FIRST PATIENT’S ENROLMENT

8 January 2013.

Funding and public reporting strategies for reducing multiple pregnancy from fertility treatments

The health of children born through assisted reproductive technologies (ART) is particularly vulnerable to policy decisions and market forces that play out before they are even conceived. ART treatment is costly, and public and third-party funding varies significantly between and within countries, leading to considerable variation in consumer affordability globally. These relative cost differences affect not only who can afford to access ART treatment, but also how ART is practiced in terms of embryo transfer practices, with less affordable treatment creating a financial incentive to transfer more than one embryo to maximize the pregnancy rates in fewer cycles. One mechanism for reducing the burden of excessive multiple pregnancies is to link insurance coverage to the number of embryos that can be transferred; another is to combine supportive funding with patient and clinician education and public reporting that emphasizes a "complete" ART cycle (all embryo transfers associated with an egg retrieval) and penalizes multiple embryo transfers. Improving funding for fertility services in a way that respects clinician and patient autonomy and allows patients to undertake a sufficient number of cycles to minimize moral hazard improves outcomes for mothers and babies while reducing the long-term economic burden associated with fertility treatments.

Changes in thyroid function during controlled ovarian hyperstimulation (COH) and its impact on assisted reproduction technology (ART) outcomes: a systematic review and meta-analysis

BACKGROUND

To investigate the thyroid function changes during controlled ovarian hyperstimulation (COH) and ascertain its impact on reproductive outcomes.

METHODS

We conducted meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive literature search was performed to identify studies reported changes in thyroid parameters during COH. We analyzed thyroid-stimulating hormone (TSH) levels, free thyroxin (fT4) levels, changes in estrogens (E2), thyroxine-binding globulin (TBG), relative risks (RRs) of clinical pregnancy rate (CPR), live birth rate (LBR), and mean difference (MD) of TSH increment between the miscarriage group and ongoing pregnancy group.

RESULTS

This meta-analysis included fifteen individual studies (n = 1665 subjects). At the end of COH, the mean TSH (2.53 mIU/L; 95% CI, 2.19 to 2.88; I² = 92.9%) exceeded the upper limit (2.5 mIU/L) and remained above the threshold until one month following embryo transfer (ET). Thyroxin decreased from baseline to the end of COH (-0.18 ng/l; 95% CI, -0.35 to 0.00; I² = 92.2%). The CPR and LBR of patients with TSH exceeding the cutoff after COH were significantly lower than those of patients with TSH below the threshold (CPR: RR, 0.62; 95% CI, 0.47 to 0.82; I² = 0.0% and LBR: RR, 0.64; 95% CI, 0.44 to 0.92; I² = 0.0%). The MD of the increment in TSH levels between the miscarriage and ongoing pregnancy groups was 0.40 mIU/L (95% CI, 0.15 to 0.65; I² = 0.0%).

CONCLUSIONS

This meta-analysis shows that TSH increases and fT4 decreases during COH. COH-induced thyroid disorder impairs reproductive outcomes.

The depot GnRH agonist protocol improves the live birth rate per fresh embryo transfer cycle, but not the cumulative live birth rate in normal responders: a randomized controlled trial and molecular mechanism study

STUDY QUESTION

Do cumulative live birth rates (CLBRs) after one complete ART cycle differ between the three commonly used controlled ovarian stimulation (COS) protocols (GnRH antagonist, depot GnRHa (GnRH agonist) and long GnRHa) in normal responders undergoing IVF/ICSI?

SUMMARY ANSWER

There were similar CLBRs between the GnRH antagonist, depot GnRHa and long GnRHa protocols.

WHAT IS KNOWN ALREADY

There is no consensus on which COS protocol is the most optimal in women with normal ovarian response. The CLBR provides the final success rate after one complete ART cycle, including the fresh and all subsequent frozen-thawed embryo transfer (ET) cycles. We suggest that the CLBR measure would allow for better comparisons between the different treatment protocols.

STUDY DESIGN, SIZE, DURATION

A prospective controlled, randomized, open label trial was performed between May 2016 and May 2017. A total of 819 patients were allocated to the GnRH antagonist, depot GnRHa or long GnRHa protocol in a 1:1:1 ratio. The minimum follow-up time from the first IVF cycle was 2 years. To further investigate the potential effect of COS with the GnRH antagonist, depot GnRHa or long GnRHa protocol on endometrial receptivity, the expression of homeobox A10 (HOXA10), myeloid ecotropic viral integration site 1 (MEIS1) and leukemia inhibitory factor (LIF) endometrial receptivity markers was evaluated in endometrial tissue from patients treated with the different COS protocols.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Infertile women with normal ovarian response (n = 819) undergoing IVF/ICSI treatment were randomized to the GnRH antagonist, depot GnRHa or long GnRHa protocol. Both IVF and ICSI cycles were included, and the sperm samples used were either fresh or frozen partner ejaculates or frozen donor ejaculates. The primary outcome was the live birth rate (LBR) per fresh ET cycle, and the CLBR after one complete ART cycle, until the birth of a first child (after 28 weeks) or until all frozen embryos were used, whichever occurred first. Pipelle endometrial biopsies from 34 female patients were obtained on Days 7-8 after oocyte retrieval or spontaneous ovulation in natural cycles, respectively, and HOXA10, MEIS1 and LIF mRNA and protein expression levels in the human endometrium was determined by quantitative real-time PCR and western blot, respectively.

MAIN RESULTS AND THE ROLE OF CHANCE

There were no significant differences in CLBRs between the GnRH antagonist, depot GnRHa or long GnRHa protocol (71.4 versus 75.5 versus 72.2%, respectively). However, there was a significantly higher LBR per fresh ET cycle in the depot GnRHa protocol than in the long GnRHa and GnRH antagonist protocols (62.6 versus 52.1% versus 45.6%, P < 0.05). Furthermore, HOXA10, MEIS1 and LIF mRNA and protein expression in endometrium all showed significantly higher in the depot GnRHa protocol than in the long GnRHa and GnRH antagonist protocols (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

A limitation of our study was that both our clinicians and patients were not blinded to the randomization for the randomized controlled trial (RCT). An inclusion criterion for the current retrospective cohort study was based on the 'actual ovarian response' during COS treatment, while the included population for the RCT was 'expected normal responders' based on maternal age and ovarian reserve test. In addition, the analysis was restricted to patients under 40 years of age undergoing their first IVF cycle. Furthermore, the endometrial tissue was collected from patients who cancelled the fresh ET, which may include some patients at risk for ovarian hyperstimulation syndrome, however only patients with 4-19 oocytes retrieved were included in the molecular study.

WIDER IMPLICATIONS OF THE FINDINGS

The depot GnRH agonist protocol improves the live birth rate per fresh ET cycle, but not the cumulative live birth rate in normal responders. A possible explanation for the improved LBR after fresh ET in the depot GnRHa protocol could be molecular signalling at the level of endometrial receptivity.

STUDY FUNDING/COMPETING INTEREST(S)

This project was funded by Grant 81571439 from the National Natural Sciences Foundation of China and Grant 2016YFC1000206-5 from the National Key Research & Development Program of China. The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

The RCT trial was registered at the Chinese Clinical Trial Registry, Study Number: ChiCTR-INR-16008220.

TRIAL REGISTRATION DATE

5 April 2016.

DATE OF FIRST PATIENT’S ENROLLMENT

12 May 2016.

Prenatal growth trajectories and birth outcomes after frozen-thawed extended culture embryo transfer and fresh embryo transfer: the Rotterdam Periconception Cohort

RESEARCH QUESTION

Are there differences in prenatal growth trajectories and birth outcomes between singleton pregnancies conceived after IVF treatment with frozen-thawed extended culture embryo transfer at day 5, fresh embryo transfer at day 3 or naturally conceived pregnancies?

DESIGN

From a prospective hospital-based cohort, 859 singleton pregnancies were selected, including 133 conceived after IVF with frozen-thawed embryo transfer, 276 after fresh embryo transfer, and 450 naturally conceived pregnancies. Longitudinal 3D ultrasound scans were performed at 7, 9 and 11 weeks of gestation for offline crown-rump length (CRL) and embryonic volume measurements. Second trimester estimated fetal weight was based on growth parameters obtained during the routine fetal anomaly scan at 20 weeks of gestation. Birth outcome data were collected from medical records.

RESULTS

No differences regarding embryonic growth trajectories were observed between frozen-thawed and fresh embryo transfer. Birthweight percentiles after fresh embryo transfer were lower than after frozen-thawed embryo transfer (38.0 versus 48.0; P = 0.046, respectively). The prevalence of non-iatrogenic preterm birth (PTB) was significantly lower in pregnancies resulting from fresh embryo transfer compared with frozen-thawed embryo transfer (4.7% versus 10.9%; P = 0.026, respectively). Compared with naturally conceived pregnancies, birthweight percentiles and percentage of non-iatrogenic PTB were significantly lower in pregnancies after fresh embryo transfer and gestational age at birth was significantly higher.

CONCLUSIONS

This study shows that embryonic growth is comparable between singleton pregnancies conceived after fresh and frozen-thawed embryo transfer. The lower relative birthweight and PTB rate in pregnancies after fresh embryo transfer than after frozen-thawed embryo transfer and naturally conceived pregnancies warrants further investigation.

A systematic review of clinical efficacy of frozen-thawed embryos and fresh embryos in in-vitro fertilization cycles

BACKGROUND

Frozen-thawed embryo (FTE) and fresh embryo (FE) transfer are two common strategies in vitro fertilization (IVF), while the results and findings still vary among studies.

METHODS

We searched multiple databases for relevant studies comparing the clinical effects of FTE and FE. Meta-analyses were conducted with Review Manager 5.0 to assess the efficacy among included articles. We also analyzed the risk of bias for the reports.

RESULTS

Nine studies eventually met the inclusion criteria from 2010 to 2018, and 11396 patients were included. The meta-analyses indicated no significant difference in biochemical pregnancy, clinical pregnancy and ongoing pregnancy rates. Meanwhile, the implantation rate and live birth rate in frozen-thawed embryos were much higher than those of fresh embryo. The birth weight in the frozen-thawed ET group was greater than that of the FE group, and the low birth weight rate in FTE was lower than FE group.

CONCLUSION

Our findings suggested a trend toward favouring frozen-thawed FTE might be a preferred transfer strategy for patients with IVF.