Lower serum LH level was related to poor embryo quality and adverse pregnancy outcomes in fixed GnRH antagonist protocol with estradiol pretreatment

OBJECTIVE

To disclose the relationships between serum LH and reproductive outcomes in Gonadotropin-releasing hormone (GnRH) antagonist protocol pretreated with luteal estradiol.

METHODS

371 patients, pretreated with estradiol, followed the GnRH antagonist protocol. They were divided into four groups based on the quartiles of serum LH levels on the day of gonadotropin (Gn) initiation(LHGI) and trigger (LHtrigger). Data on various pregnancy outcomes were collected.

RESULTS

As serum LHGI increased, anti-Müllerian hormone (AMH) level, antral follicle count (AFC), LHtrigger, estradiol (E2) and P on the trigger day, E2/oocytes, and oocyte numbers increased and peaked in Q4, while Gn dose decreased. Good-quality embryo and blast formation rates increased and peaked in Q3. LHGI <3.93 mIU/ml impaired ongoing pregnancy rate and LBR. After adjusting for AMH and AFC, the impacts were not significant. As LHtrigger increased, E2/oocytes and good-quality embryo rate increased and peaked in T4 and implantation rate increased and peaked in T3. LHtrigger <1.49 mIU/ml independently influenced clinical pregnancy rate (CPR) after adjusting for AMH and AFC. LHGI was positively related to AMH, AFC, LHtrigger, blast formation rate and negatively related to BMI, age and Gn dose. LHtrigger was positively related to E2/oocytes and good quality embryo rate.

CONCLUSIONS

Lower serum LH represents as a potential indicator for embryo quality and reproductive outcomes in GnRH antagonist fixed protocol pretreated with estradiol. Early identification of excessive suppression of LH levels will benefit individuals with normal ovarian reserve more.

"Try until the last?"-the relevance of fresh embryo transfer outcomes for subsequent same-cohort vitrified-warmed cycles

PURPOSE

Taking into consideration earlier attempts at assisted reproduction and previous pregnancies allows a more differentiated approach when counseling couples regarding their chances in assisted reproductive treatments. The aim of this study was to investigate whether the outcome of fresh embryo transfers affects subsequent same-cohort vitrified-warmed cycles.

METHODS

This retrospective cohort study analyzes the outcome of all fresh and frozen embryo transfers (n = 8118) between January 1, 2011, and December 31, 2022. All women who received fresh or frozen embryo transfers at Kepler University Hospital Linz were included. The use of donor eggs, previously cryopreserved oocytes, and freeze-all cycles were excluded from the analysis.

RESULTS

Positive serum βhCG after a fresh cycle has a significant impact on the chances of positive βhCG in a subsequent vitrified-warmed cycle (36.3% [33.2%, 39.5%]; P = 0.002). Negative βhCG after a fresh cycle does not predict the outcome of the following same-cohort embryo transfer (33.1% [30.7%, 35.7%], P = 0.726). Pregnancy rates of the first, second, third, and fourth same-cohort vitrified-warmed embryo transfer remain continuously high, with 32.8%, 30.8%, 28.9%, and 27.1%, respectively.

CONCLUSIONS

Positive serum βhCG after a fresh embryo transfer has a positive predictive value for the outcome of a subsequent vitrified-warmed embryo transfer. Couples with a negative fresh cycle should not be discouraged from continuing fertility treatment using same-cohort frozen embryos.

TRIAL REGISTRATION

This study was prospectively registered at the German Clinical Trials Register on September 5, 2023 (DRKS00032552).

GnRH agonist pretreatment for frozen embryo transfer among women with polycystic ovary syndrome: a narrow systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Frozen embryo transfer (FET) is usually recommended for women with polycystic ovary syndrome (PCOS) undergoing In vitro fertilization (IVF). While there is no consensus as to the optimal protocol of endometrial preparation for FET. The effect of gonadotropin-releasing hormone agonist (GnRH-a) pretreatment for FET among women with PCOS remains controversial.

PURPOSE

We intend to explore whether GnRH-a pretreatment could improve clinical outcomes for women with PCOS undergoing FET.

METHODS

PubMed, Embase, ClinicalTrials.gov, Cochrane Library, and Web of Science were searched up to May 16, 2024. Eligible studies involved patients with PCOS undergoing FET and receiving GnRH-a pretreatment for endometrial preparation, with artificial cycle (AC) as the control therapy. Only randomized controlled trials (RCTs) published in Chinese and English were included. Data extraction was performed independently by two authors. Effect was quantified using odd ratios (ORs) with 95% confidence intervals (CIs) using random-effect models with the Mantel-Hansel (M-H) method in Revman software. Quality of outcomes was evaluated using the GRADEpro system. Primary outcomes contained the clinical pregnancy rate, miscarriage rate, and live birth rate. Secondary outcomes included the incidence of preterm labor and gestational diabetes mellitus (GDM).

RESULTS

Ninety-seven records were initially retrieved, with 21 duplicates and 65 articles excluded after title and abstract screening. Seven studies were excluded due to retrospective design, leaving three RCTs with 709 participants. Among them, 353 received GnRH-a pretreatment as the intervention group and 356 received AC as the control group. No significant differences were observed in the clinical pregnancy rate (OR 1.09, 95% CI 0.75 to 1.56, P = 0.66), miscarriage rate (OR 0.73, 95% CI 0.28 to 1.90, P = 0.52), live birth rate (OR 0.87, 95% CI 0.61 to 1.25, P = 0.46), and the risk of preterm labor (OR 1.45, 95% CI 0.79 to 2.65, P = 0.23) and GDM (OR 0.73, 95% CI 0.37 to 1.48, P = 0.39) between the two groups.

CONCLUSIONS

In this meta-analysis, GnRH-a pretreatment does not confer any advantages and appears unnecessary for women with PCOS undergoing FET. Additional RCTs should focus on maternal complications and the health of offspring.

Differences in perinatal complications and serum hormone levels due to uterine endometrial preparation methods in frozen-thawed embryo transfer

AIM

In frozen-thawed embryo transfer (FET), differences in endometrial preparation methods affect the incidence of perinatal complications. However, the underlying causes are unclear. We aimed to investigate whether serum E2, P4 levels are associated with perinatal complications.

METHODS

This is a retrospective cohort study, involving 306 successful FET pregnancies from 2017 to 2022. Participants were divided into Natural Cycle (NC) and Hormone Replacement Cycle (HRC) group. We compared serum hormone levels, maternal backgrounds, and perinatal outcomes and complications. Furthermore, within the HRC group, serum hormone levels were compared for perinatal complications previously reported to show differences in incidence rates depending on the method of endometrial preparation.

RESULTS

HRC exhibited significantly higher serum E2 levels during the implantation period, but lower P4 levels during ovulation, implantation, and pregnancy test period compared with NC. HRC also had significantly higher rates of postpartum hemorrhage (PPH) and placenta accreta spectrum (PAS). There was no association found between perinatal complications more likely to occur in HRC and serum E2, P4 levels.

CONCLUSIONS

In HRC, there were more occurrences of PPH and PAS. Although serum E2, P4 levels during FET did not correlate with perinatal complications.

Effects of the Zishen Yutai Pill on live births compared with placebo among infertile women with frozen-thawed embryo transfer cycle: A multicentre double-blind randomized controlled trial

BACKGROUND

Zishen Yutai Pill exhibited clinical benefit to infertile women undergoing fresh embryo transfer cycles, improving their pregnancy outcomes. However, as the endometrial environment in frozen embryo transfer (FET) is different from fresh cycles, the effects of ZYP on fresh embryo transfer could not be generalized to FET.

OBJECTIVE

We aimed to explore the effects of ZYP on live birth rate in women's FET cycles.

METHODS

This multicentre, double-blind, placebo-controlled, randomized study was conducted at 11 reproductive medical centres in China. Women were recruited and randomly assigned to ZYP or placebo intervention (5 g once, 3 times per day) around the time of FET. The live birth rate was set as the primary outcome. Secondary outcomes included implantation rate, biochemical pregnancy rate, clinical pregnancy rate, pregnancy loss rates. Data was analyzed based on the intention-to-treat principle, with per protocol analysis as sensitivity analysis.

RESULTS

Between December 2017 and April 2019, 934 women were screened, of whom 880 met all eligibility criteria and were allocated to ZYP (n=441) or placebo (n=439). In ITT analysis, the live birth rates were 38.32% (169/441) in ZYP group and 32.57% (143/439) (absolute difference 5.75%, 95%CI [-0.57%, 12.00%], OR 1.29, 95%CI [0.98, 1.70], P=0.08). The intervention of ZYP did not result in significantly differences in all secondary outcomes compared with placebo (all P>0.05). Similar trends were observed in PP analysis. In post hoc analysis, ZYP resulted in higher rates of live birth than placebo among women in specific subgroups, i.e., with miscarriage history (39.23% vs. 26.45%, P=0.01) or advanced maternal age (33.93% vs. 21.85%, P=0.04).

CONCLUSION

In infertile women undergoing FET cycle, intervention with ZYP led to a trend of live birth rate increment compared with placebo, but without statistical significance. However, women with miscarriage history and advanced age could experience possible benefits from ZYP intervention.

REGISTRATION

ChiCTR-INR-17010809 (http://www.chictr.org.cn).

Effect of ART treatments on maternal and neonatal outcomes in singleton live births: A large-scale retrospective cohort study

Background

The increased risk of pregnancy complications in the ART population has been reported, but the source of these risks remains controversial. The study aims to evaluate the association between ART treatments and patient characteristics with maternal and neonatal outcomes.

Methods

This was a retrospective analysis of 45,159 singleton pregnant women at a hospital between 2018 and 2021. The maternal and neonatal outcomes included pregnancy-induced hypertension (PIH), preeclampsia (PE), gestational diabetes mellitus (GDM), placental abruption (PA), placenta accreta spectrum (PAS), postpartum hemorrhage (PPH), cesarean section, iatrogenic and spontaneous preterm birth, small for gestational age (SGA), low birth weight (LBW), macrosomia, and birth defects. We assessed the outcomes among the fresh embryo transfer (ET), frozen embryo transfer (FET), and spontaneous conception (SC) groups. Potential risk factors were further analyzed in the ART population.

Results

FET was associated with higher risks for PIH (SC: AOR, 1.97(1.51-2.57); fresh ET: AOR, 1.68(1.03-2.72)), PE (SC: 2.28(1.86-2.80); fresh ET: AOR, 1.61(1.11-2.33)), PAS (SC: AOR, 3.89(3.39-4.46); fresh ET: AOR, 2.23(1.70-2.92)), PPH (SC: AOR, 3.46(2.76-4.34)); fresh ET: 2.09(1.39-3.14)), and macrosomia (SC: 1.53(1.25-1.86); fresh ET: AOR, 2.87(1.89-4.35). Fresh ET was associated with higher risks for PA (SC: AOR, 2.19(1.51-3.18); FET: AOR, 0.39(0.17-0.90)), SGA (SC: AOR, 1.56(1.06-2.31), FET: AOR, 0.42(0.19-0.91)), and LBW (SC: AOR, 2.24(1.82-2.77), FET: AOR, 0.63 (0.44-0.89)), and fresh ET is an independent risk factor for PA and SGA. Furthermore, the risk of GDM was associated with the biological characteristic of low-fertility patients.

Conclusions

Embryo status (fresh or frozen) is a key factor affecting the maternal and neonatal outcomes in ART treatments, while biological characteristics of infertile patients also play a certain role.

Recryopreservation impairs blastocyst implantation potential via activated endoplasmic reticulum stress pathway and induced apoptosis

Recryopreservation (recryo) is occasionally applied in clinical, while the underlying mechanism of impaired clinical outcomes after recryo remains unclear. In this study, frozen embryo transfer (FET) cycles of single blastocyst transfer in an academic reproductive medicine center were enrolled. According to the number of times blastocysts experienced cryopreservation, they were divided into the cryopreservation (Cryo) group and the Recryo group. Donated human blastocysts were collected and detected for mechanism exploration. It was found that recryo procedure resulted in impaired blastocyst developmental potential, including decreased implantation rate, reduced biochemical pregnancy rate, declined clinical pregnancy rate, higher early miscarriage rate, and lower live birth rate. Moreover, recryo led to impaired trophectoderm (TE) function, exhibiting lower human chorionic gonadotropin levels 12 days after FET. In addition, single-cell RNA sequencing showed that the expression of genes involved in cell adhesion and embryo development were altered. More specifically, activated endoplasmic reticulum (ER) pathway and induced apoptosis were further verified by immunofluorescence and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay involving in the recryo procedure. In conclusion, recryo could interfere with the process of blastocyst implantation by impairing TE function, affecting blastocyst adhesion, activating ER stress pathway and inducing apoptosis. It provides caution to embryologists about the potential risk of recryopreservation.

Fresh versus Frozen Embryo Transfer in In Vitro Fertilization/Intracytoplasmic Sperm Injection Cycles: A Systematic Review and Meta-Analysis of Neonatal Outcomes

Background and Objectives: Although considerable research has been devoted to examining the distinctions between fresh and frozen embryo transfer regarding obstetric outcomes and rates of pregnancy success, there is still a scarcity of thorough analyses that specifically examine neonatal outcomes. The objective of our study was to provide an in-depth analysis of neonatal outcomes that occur after the transfer of fresh and frozen embryos (ET vs. FET) in IVF/ICSI cycles. Materials and Methods: Multiple databases (PubMed/MEDLINE, Cochrane Library, Web of Science, Wiley, Scopus, Ovid and Science Direct) were searched from January 1980 to February 2024. Two reviewers conducted the article identification and data extraction, meeting inclusion and exclusion criteria. The methodological quality was evaluated using the Newcastle-Ottawa Scale (NOS) or the revised Cochrane Risk of Bias Tool. The meta-analysis was performed using RevMan 5.4. Results: Twenty studies, including 171,481 participants in total, were subjected to qualitative and quantitative analyses. A significant increase in preterm birth rates was noted with fresh embryo transfer compared to FET in the overall IVF/ICSI population (OR 1.26, 95% CI 1.18-1.35, p < 0.00001), as well as greater odds of a low birth weight (OR 1.37, 95% CI 1.27-1.48, p < 0.00001) and small-for-gestational-age infants in this group (OR 1.81, 95% CI 1.63-2.00, p < 0.00001). In contrast, frozen embryo transfer can result in macrosomic (OR 0.59, 95% CI 0.54-0.65, p < 0.00001) or large-for-gestational-age infants (OR 0.64, 95% CI 0.60-0.69, p < 0.00001). No significant difference was observed regarding congenital malformations or neonatal death rates. Conclusions: This systematic review confirmed that singleton babies conceived by frozen embryo transfer are at lower risk of preterm delivery, low birthweight and being small for gestational age than their counterparts conceived by fresh embryo transfer. The data support embryo cryopreservation but suggest that elective freezing should be limited to cases with a proven indication or within the framework of a clinical study.

Association between endometrial thickness and birthweight of singletons from vitrified-warmed cycles: a retrospective cohort study

RESEARCH QUESTION

What is the association between endometrial thickness (EMT) and the birthweight of singleton infants born from frozen-thawed embryo transfer cycles?

DESIGN

This retrospective cohort study was conducted from January 2016 to December 2019. Participants were categorized into a natural cycle (NC, n = 8132) group and hormone replacement therapy (HRT, n = 4975) group. Only singleton deliveries were included. The primary outcomes were measures of birthweight and relevant indexes. Multivariable logistic regression and multivariable-adjusted linear regression models that incorporated restricted cubic splines were used.

RESULTS

In the HRT group, the risk of delivering a small for gestational age (SGA) infant was increased in women with an EMT <8.0 mm (adjusted odds ratio [aOR] 1.85, 95% confidence interval [CI] 1.17-2.91) compared with women with an EMT of 8.0 to <12.0 mm, and increased with an EMT ≥12.0 mm (aOR 1.85, 95% CI 1.03-3.33). An inverted U-shaped relationship was found between EMT and birthweight in women with HRT. No significant differences were shown in birthweight z-score, or being SGA or large for gestational age, in singletons among the three EMT groups in the natural cycles.

CONCLUSIONS

A thinner endometrium seen in women undergoing HRT cycles was associated with a lower birthweight z-score, as well as a higher risk of SGA. However, no significant association was observed between EMT and birthweight z-score or SGA in the NC group. It is noteworthy that a thicker endometrium was not associated with a higher birthweight in frozen-thawed embryo transfer (FET) cycles. Women with a thin endometrium who achieve pregnancy require specialized attention, particularly if they are undergoing FET with HRT cycles.

Single day 14 serum hCG values allow prediction of viable pregnancy and are significantly higher in frozen as compared to fresh single blastocyst transfer

PURPOSE

To evaluate if single serum human chorionic gonadotropin (hCG) level measurements are sufficient for pregnancy monitoring after single embryo transfer (sET) and to compare the hCG levels between fresh (FRET) and frozen embryo transfers (FET) in medically assisted reproduction.

METHODS

This was a retrospective exploratory cohort study including all patients who met the inclusion criteria, who received a single FRET (n = 249) or FET (n = 410) of a day five blastocyst at the IVF clinic at the Johannes Kepler University Linz between 2011 and 2020. hCG levels were measured on day 14 after embryo transfer. Threshold values for the viability of pregnancies were determined using receiver operating characteristic (ROC) curves.

RESULTS

Significantly higher hCG levels were found in those who received FET than in those who received FRET (1222.8 ± 946.7 mU/ml vs. 862.7 ± 572.9 mU/ml; p < 0.001). Optimal threshold values predicting a viable pregnancy were 368.5 mU/ml and 523 mU/ml in the FRET and FET groups, respectively.

CONCLUSIONS

After FET, higher hCG values after 14 days of embryo transfer must be considered in pregnancy monitoring. Additionally, a single threshold hCG value seems to be sufficient for determining pregnancy viability. To exclude ectopic pregnancies, subsequent ultrasound examination is a mandatory requirement.

Comparison of clinical outcomes and perinatal outcomes between natural cycle and hormone replacement therapy of frozen-thawed embryo transfer in patients with regular menstruation: a propensity score-matched analysis

Purpose

To investigate potential differences in pregnancy outcomes among patients with regular menstruation who underwent frozen-thawed embryo transfer using natural cycle (NC) or hormone replacement therapy (HRT).

Methods

This study retrospectively analyzed 2672 patients with regular menstruation who underwent FET from November 2015 to June 2021 at the single reproductive medical center. A one-to-one match was performed applying a 0.02 caliper with propensity score matching. Independent factors influencing the live birth and clinical pregnancy rates were screened and developed in the nomogram by logistic regression analysis. The efficacy of live birth rate and clinical pregnancy rate prediction models was assessed with the area under the ROC curve, and the live birth rate prediction model was internally validated within the bootstrap method.

Results

The NC protocol outperformed the HRT protocol in terms of clinical pregnancy and live birth rates. The stratified analysis revealed consistently higher live birth and clinical pregnancy rates with the NC protocol across different variable strata compared to the HRT protocol. However, compared to the HRT treatment, perinatal outcomes indicated that the NC protocol was related to a higher probability of gestational diabetes. Multifactorial logistic regression analysis demonstrated independent risk factors for live birth rate and clinical pregnancy rate. To predict the two rates, nomogram prediction models were constructed based on these influencing factors. The receiver operating characteristic curve demonstrated moderate predictive ability with an area under curve (AUC) of 0.646 and 0.656 respectively. The internal validation of the model for live birth rate yielded an average AUC of 0.646 implying the stability of the nomogram model.

Conclusion

This study highlighted that NC yielded higher live birth and clinical pregnancy rates in comparison to HRT in women with regular menstruation who achieved successful pregnancies through frozen-thawed embryo transfer. However, it might incur a higher risk of developing gestational diabetes.

Safety of embryo cryopreservation: insights from mid-term placental transcriptional changes

BACKGROUND

In recent years, with benefits from the continuous improvement of clinical technology and the advantage of fertility preservation, the application of embryo cryopreservation has been growing rapidly worldwide. However, amidst this growth, concerns about its safety persist. Numerous studies have highlighted the elevated risk of perinatal complications linked to frozen embryo transfer (FET), such as large for gestational age (LGA) and hypertensive disorders during pregnancy. Thus, it is imperative to explore the potential risk of embryo cryopreservation and its related mechanisms.

METHODS

Given the strict ethical constraints on clinical samples, we employed mouse models in this study. Three experimental groups were established: the naturally conceived (NC) group, the fresh embryo transfer (Fresh-ET) group, and the FET group. Blastocyst formation rates and implantation rates were calculated post-embryo cryopreservation. The impact of FET on fetal growth was evaluated upon fetal and placental weight. Placental RNA-seq was conducted, encompassing comprehensive analyses of various comparisons (Fresh-ET vs. NC, FET vs. NC, and FET vs. Fresh-ET).

RESULTS

Reduced rates of blastocyst formation and implantation were observed post-embryo cryopreservation. Fresh-ET resulted in a significant decrease in fetal weight compared to NC group, whereas FET reversed this decline. RNA-seq analysis indicated that the majority of the expression changes in FET were inherited from Fresh-ET, and alterations solely attributed to embryo cryopreservation were moderate. Unexpectedly, certain genes that showed alterations in Fresh-ET tended to be restored in FET. Further analysis suggested that this regression may underlie the improvement of fetal growth restriction in FET. The expression of imprinted genes was disrupted in both FET and Fresh-ET groups.

CONCLUSION

Based on our experimental data on mouse models, the impact of embryo cryopreservation is less pronounced than other in vitro manipulations in Fresh-ET. However, the impairment of the embryonic developmental potential and the gene alterations in placenta still suggested it to be a risky operation.

Mother, father, son and the Italian Law 40/2004. No 'delete' key

Assisted reproductive technology (ART) has emerged in recent years as a point of significant innovation in the medical field but is also controversial from a bioethical and legal standpoint. In the Italian context, this matter is regulated by Law 40/2004, which specifically requires that informed consent should be obtained from both members of a couple before proceeding with any ART procedure. This consent is deemed irrevocable at the moment of egg fertilization. Recently, a ruling by the Italian Constitutional Court on this matter elicited controversy. The decision permitted embryo transfer even in a case of parental separation, notwithstanding the father's explicit opposition. The Court emphasized the priority of the woman's psychophysical health over the man's, highlighting the traumatic consequences of interrupting the undertaken path. As a result, both the man's right to self-determination regarding the decision to become a father and the need for informed consent at every stage of medical procedures have been downplayed. Moreover, the extensive utilization of procedures like embryo cryopreservation, with associated parental implications, particularly concerning the time frame and the actuality of informed consent, is posing challenges to the initial application framework of Law 40/2004. The objective of this Commentary is to scrutinize and discuss the issues mentioned above.

Obstetric Characteristics and Outcomes of Gestational Carrier Pregnancies: A Systematic Review and Meta-Analysis

Importance

Advancements in assisted reproductive technology (ART) have led to an increase in gestational carrier (GC) pregnancies. However, the perinatal outcomes of GC pregnancies remain understudied, necessitating a deeper understanding of their associated risks.

Objective

To assess maternal characteristics and obstetric outcomes associated with GC pregnancies.

Data Sources

A comprehensive systematic search of publications published before October 31, 2023, using PubMed, Web of Science, Scopus, and Cochrane Library databases was conducted.

Study Selection

Two authors selected studies examining obstetric characteristics and outcomes in GC pregnancies with 24 or more weeks' gestation. Studies with insufficient outcome information, unavailable data on gestational surrogacies, and non-English language studies were excluded.

Data Extraction and Synthesis

Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, 2 investigators extracted and synthesized both quantitative and qualitative data. Both fixed-effect and random-effect analysis were used to pool data.

Main Outcomes and Measures

The primary outcomes were obstetric characteristics and outcomes, including hypertensive disorders, preterm birth, and low birth weight. Secondary outcomes included severe maternal morbidity and mortality associated with GC pregnancies.

Results

Six studies from 2011 to 2023 involving 28 300 GC pregnancies and 1 270 662 non-GC pregnancies were included. GCs accounted for 2.5% of in vitro fertilization cycles (59 502 of 2 374 154 cycles) and 3.8% of ART pregnancies (26 759 of 701 047 ART pregnancies). GC pregnancies were more likely to be conceived by frozen embryo transfer compared with non-GC ART pregnancies (odds ratio [OR], 2.84; 95% CI, 1.56-5.15), and rates of single embryo transfer were similar between the 2 groups (OR, 1.18; 95% CI, 0.94-1.48). GCs were rarely nulliparous (6 of 361 patients [1.7%]) and were more likely to have multifetal pregnancies compared with non-GC ART patients (OR, 1.18; 95% CI, 1.02-1.35). Comparator studies revealed lower odds of cesarean delivery (adjusted OR [aOR], 0.42; 95% CI, 0.27-0.65) and comparable rates of hypertensive disorders (aOR, 0.86; 95% CI, 0.45-1.64), preterm birth (aOR, 0.82; 95% CI, 0.68-1.00), and low birth weight (aOR, 0.79; 95% CI, 0.50-1.26) in GC pregnancies vs non-GC ART pregnancies. Comparatively, GC pregnancies had higher odds of hypertensive disorders (aOR, 1.44; 95% CI, 1.13-1.84) vs general (non-GC ART and non-ART) pregnancies with comparable cesarean delivery risk (aOR, 1.06; 95% CI, 0.90-1.25). Preterm birth and low birth weight data lacked a comparative group using multivariate analysis. Severe maternal morbidity and maternal mortality were rare among GCs.

Conclusions and Relevance

In this systematic review and meta-analysis, although GC pregnancies had slightly improved outcomes compared with non-GC ART pregnancies, they posed higher risks than general pregnancies. Contributing factors may include ART procedures and increased rates of multiple gestations which influence adverse perinatal outcomes in GC pregnancies.

Embryo transfer impact: a comprehensive national cohort analysis comparing maternal and neonatal outcomes across varied embryo stages in fresh and frozen transfers

Introduction

The utilization of frozen embryo transfer not only enhances reproductive outcomes by elevating the likelihood of live birth and clinical pregnancy but also improves safety by mitigating the risks associated with ovarian hyperstimulation syndrome (OHSS) and multiple pregnancies. There has been an increasing debate in recent years regarding the advisability of making elective frozen embryo transfer the standard practice. Our study aims to determine the optimal choice between fresh and frozen embryo transfer, as well as whether the transfer should occur at the cleavage or blastocyst stage.

Method

In this retrospective cohort study conducted in Taiwan, data from the national assisted reproductive technology (ART) database spanning from January 1st, 2013, to December 31st, 2017, were analyzed. The study included 51,762 eligible female participants who underwent ART and embryo transfer. Pregnancy outcomes, maternal complications, and singleton neonatal outcomes were evaluated using the National Health Insurance Database from January 1st, 2013, to December 31st, 2018. Cases were categorized into groups based on whether they underwent fresh or frozen embryo transfers, with further subdivision into cleavage stage and blastocyst stage transfers. Exposure variables encompassed clinical pregnancy rate, live birth rate, OHSS, pregnancy-induced hypertension, gestational diabetes mellitus (DM), placenta previa, placental abruption, preterm premature rupture of membranes (PPROM), gestational age, newborn body weight, and route of delivery.

Results

Frozen blastocyst transfers showed higher rates of clinical pregnancy (CPR) and live births (LBR) compared to fresh blastocyst transfers. Conversely, frozen cleavage stage transfers demonstrated lower rates of clinical pregnancy and live birth compared to fresh cleavage stage transfers. Frozen embryo transfers were associated with reduced risks of OHSS but were linked to a higher risk of pregnancy-induced hypertension compared to fresh embryo transfers. Additionally, frozen embryo transfers were associated with a higher incidence of large for gestational age infants and a lower incidence of small for gestational age infants.

Conclusion

The freeze-all strategy may not be suitable for universal application. When embryos can develop to the blastocyst stage, FET is a favorable choice, but embryos can only develop to the cleavage stage, fresh embryo transfer becomes a more reasonable option.

Current research of Assisted Reproductive Technology for women with early endometrial cancer and atypical endometrial hyperplasia after conservative treatment

As the incidence of endometrial cancer (EC) and atypical endometrial hyperplasia (AEH) has been increasing, and has shown young trend. It is crucial to study the fertility-preserving treatment of endometrial lesions and fertility-promoting protocols. Age, obesity, and irregular ovulation are not only high-risk factors for endometrial lesions but also key factors affecting female fertility. Assisted reproductive technology (ART) can significantly improve pregnancy outcomes in patients with AEH and EC after conservative treatment. Based on the existing studies, this article reviews the progress of research on pregnancy outcomes of ART and its influencing factors in such patients. It helps physicians in providing optimal fertility guidance.

Can serum progesterone concentration direct a fresh or freeze-all transfer strategy in the first in vitro fertilisation cycle?

PURPOSE

To examine the interaction between serum progesterone concentration on the trigger day and choice of freeze-all and fresh transfer strategies on live birth in an unselected population as well as in patients over 35 years old.

METHODS

We performed a retrospective cohort study of 26,661 patients commencing their first IVF cycle in a large fertility centre between 2015 and 2019, including 4687 patients over 35 years old. We performed a multivariable fractional polynomial interaction analysis within a logistic regression model to investigate the interaction between serum progesterone concentration and the choice of freeze-all or fresh transfer strategy following the first transfer.

RESULTS

15,539 patients underwent a fresh embryo transfer and 11,122 underwent a freeze-all strategy in their first IVF cycle. The freeze-all group had a higher live birth rate compared to the fresh group (43.9% vs 40.3%). After adjusting for confounding factors, there was a positive interaction between serum progesterone concentrations and the choice of a freeze-all versus fresh embryo transfer on live birth (p for interaction 0.0001), with a larger magnitude of effect when progesterone concentration was higher. Such an interaction was also observed in patients over 35 years old (p for interaction 0.01), but the treatment effect curve over progesterone concentrations was almost flat.

CONCLUSIONS

In an unselected population, frozen transfer is associated with greater chances of live birth, especially in patients with higher serum progesterone concentration. In patients over 35 years old, the benefit of a freeze-all policy appears small across all serum progesterone concentrations.

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.

Clinical outcomes of frozen-thawed embryo transfer in natural cycles with luteinized unruptured follicles

OBJECTIVE

To assess the effect of luteinized unruptured follicles (LUF) on frozen-thawed embryo transfer cycles performed in natural cycles (FET-NC).

METHODS

Retrospective cohort study, held in a university hospital with 3415 cycles for frozen-thawed embryo transfer, performed between June 2019 and September 2022. Using propensity score matching, 242 patients with a diagnosis of LUF (LUF group) were matched with 484 ovulated patients (ovulation group). Stratified by the type of embryo transferred, the LUF group included 168 blastocyst transfer patients (blastocyst group) and 74 cleavage-stage embryo transfer patients (cleavage-embryo group). The ovulation group included 324 patients with blastocyst transfer (blastocyst group) and 160 patients with transferred cleavage-stage embryos. Clinical pregnancy rate was retrospectively analyzed between the LUF and ovulation groups, as well as between each subgroup.

RESULTS

After using propensity score matching, the general characteristics of the LUF and ovulation groups were similar. The implantation and clinical pregnancy rates in the LUF group were not significantly different from those in the ovulation group (44.98 % vs. 45.29 %, p = 0.93; 53.72 % vs. 52.48 %, p = 0.75). The implantation and pregnancy rates of transferred cleavage-stage embryos in the LUF group were also not significantly different from those in the ovulation group (32.39 % vs. 36.40 %, p = 0.42; 47.30 % vs. 47.50 %, p = 0.98). The implantation and pregnancy rates of transferred blastocysts in the LUF group were also not significantly different from those in the ovulation group (53.11 % vs. 52.03 %, p = 0.82; 56.55 % vs. 54.94 %, p = 0.73). There was also no significant difference in the miscarriage rate between the groups.

CONCLUSION

In the natural cycle, LUF does not affect the clinical pregnancy outcomes of FET. If adequate luteal support is given, the clinical pregnancy outcomes were similar between the LUF group and ovulation group.

Association of duration of embryo culture with risk of large for gestational age delivery in cryopreserved embryo transfer cycles

OBJECTIVE

To examine the relationship between the day of embryo cryopreservation and large for gestational age (LGA) infants in women undergoing frozen embryo transfers (FETs) after cryopreservation on days 2-7 after fertilization and to compare the risk of the day of embryo cryopreservation to other possible risk factors of LGA after FET cycles.

DESIGN

Retrospective cohort study.

SETTING

Society of Assisted Reproduction Clinical Outcomes Reporting System.

PATIENTS

Women undergoing FET cycles.

INTERVENTION

Day of cryopreservation.

MAIN OUTCOME MEASURE

Singleton LGA infant.

RESULTS

A total of 33,030 (18.2%) FET cycles in the study group (n = 181,592) resulted in LGA infants during the study period of 2014-2019. There was an increase in LGA risk when cryopreservation was performed from day 2 (13.7%) to days 3-7 (14.4%, 15.0%, 18.2%, 18.5%, and 18.9%). In the log-binomial model, the risk increased compared with days 2-3 combined when cryopreservation was performed on days 5-7 (adjusted relative risk [aRR] 1.32, 95% confidence interval [CI] 1.22-1.44 for day 5, aRR 1.34, 95% CI 1.23-1.46 for day 6, and aRR 1.42, 95% CI 1.25-1.61 for day 7). Other factors most associated with LGA risk in the log-binomial model were preterm parity of >3 compared with 0 (aRR 1.82, 95% CI 1.24-2.69) and body mass index (BMI) of >35 kg/m2 compared with normal weight (aRR 1.94, 95% CI 1.88-2.01). Increasing gravity, parity, BMI, number of oocytes, and embryo grade were also associated with LGA in this model. Asian, Black, Hispanic, and combined Hawaiian and Pacific Islander were protective factors in the model compared with White patients. Low BMI (<18.5 kg/m2) was also considered a protective factor in the model compared with normal BMI.

CONCLUSION

Duration of embryo culture was associated with an increased risk of LGA in this study cohort when controlling for known confounders such as maternal BMI and parity. This study sheds new light on the possible link between FET and LGA infants.

External bending of cryodevice during vitrification leads to cryoprotectant cracks and damage to embryo blastomeres

RESEARCH QUESTION

Embryo blastomeres and the zona pellucida are occasionally damaged during vitrification; is this a result of crack-induced mechanical damage in the glass state, caused by external bending of the device?

DESIGN

A stereomicroscope was used to observe external bending-induced cracks in a cryoprotectant. Thereafter, 309 human cleavage-stage embryos derived from abnormally fertilized eggs were used to assess embryo damage under two external bending conditions: forward bending and backward bending, with three bending degrees applied. Three distinct embryo positions were used to examine the correlation between bending and embryo damage. Damage was assessed by looking at blastomere lysis rates, and overall rates of damaged and surviving embryos.

RESULTS

A series of parallel cracks were identified in the cryoprotectant used for external bending, which led to damage to the embryo blastomeres. Compared with forward bending and control, the embryos were found to be more easily damaged by backward bending, indicated by significantly higher blastomere lysis and embryo damage rates, and lower embryo survival rate of backward bending than forward bending (P < 0.001). The degree of embryo damage also increased as the degree of external forces increased. Embryo position correlated with degree of embryo damage.

CONCLUSIONS

Cryoprotectant crack-induced damage was identified as the cause of embryo damage. Mechanical damage to the glass state occurs because of improper external bending of the cryodevice strip in liquid nitrogen during vitrification. To prevent damage, bending of the strip should be avoided and the embryos should be placed near the tip of the strip.

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

STUDY QUESTION

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

SUMMARY ANSWER

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

WHAT IS KNOWN ALREADY

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

STUDY DESIGN, SIZE, DURATION

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

PARTICIPANTS/MATERIALS, SETTING, METHODS

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

MAIN RESULTS AND THE ROLE OF CHANCE

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

LIMITATIONS, REASONS FOR CAUTION

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

WIDER IMPLICATIONS OF THE FINDINGS

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

STUDY FUNDING/COMPETING INTEREST(S)

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

TRIAL REGISTRATION NUMBER

N/A.

Levels of serum β-human chorionic gonadotropin after embryo transfer and subsequent miscarriage, pre-eclampsia, and intrauterine growth restriction

Background

This study aimed to examine maternal serum concentration of β-human chorionic gonadotropin (β-hCG) on Day 16 after embryo transfer and risk of miscarriage, pre-eclampsia, and intrauterine growth restriction (IUGR).

Methods

In this study, we evaluated 125 pregnancies following in vitro fertilization (IVF). β-hCG concentrations were measured on the morning of Day 16 after embryo transfer. Baseline characteristics of the study participants were also recorded.

Results

Concentrations of β-hCG on Day 16 after embryo transfer were inversely associated with the higher risk of miscarriage (p < 0.001), but did not with pre-eclampsia and IUGR (p > 0.05). Spearman's correlation coefficient showed a reverse and significant association between β-hCG and higher risk of miscarriage (σ = 0.531 and p < 0.001). There was a significant association between frozen embryo transfer and the risk of IUGR and pre-eclampsia (p = 0.005 and p = 0.023, respectively).

Conclusions

Maternal serum concentrations of β-hCG on Day 16 after IVF/embryo transfer were associated with the higher risk of miscarriage, but not pre-eclampsia and IUGR.

Frozen autologous and donor oocytes are associated with differences in clinical and neonatal outcomes compared with fresh oocytes: a Society for Assisted Reproductive Technology Clinic Outcome Reporting System Analysis

Objective

To study the clinical and neonatal outcomes of embryos derived from frozen oocytes relative to fresh oocytes in both autologous and donor oocyte cycles after fresh embryo transfer (ET).

Design

This is a retrospective cohort study using the Society for Assisted Reproductive Technology Clinic Outcome Reporting System database between 2014 and 2015.

Setting

The Society for Assisted Reproductive Technology Clinic Outcome Reporting System database was used to identify autologous and donor oocyte cycles that resulted in a fresh ET during 2014 and 2015.

Patients

There were 154,706 total cycles identified that used embryos derived from fresh or frozen oocytes and resulted in a fresh ET, including 139,734 autologous oocyte cycles and 14,972 donor oocyte cycles.

Interventions

Generalized linear regression models were used to compare the clinical and neonatal outcomes of frozen oocytes relative to fresh oocytes. Models were adjusted for maternal age, body mass index, smoking status, parity, infertility diagnosis, number of embryos transferred, and preimplantation genetic testing. An additional sensitivity analysis was performed to examine singleton pregnancies separately.

Main Outcome Measures

The live birth (LB) rate was the primary outcome. Secondary outcomes include pregnancy and birthweight outcomes.

Results

Differences in clinical and neonatal outcomes between fresh and frozen-thawed oocytes after fresh ET were observed. Specifically, our study found a higher incidence of high-birthweight infants after the use of frozen oocytes relative to fresh oocytes in both autologous oocytes (12.5% [frozen] vs. 4.5% [fresh], adjusted risk ratio [aRR] 2.67, 95% confidence interval [CI] 1.65-4.3) and donor oocyte cycles (6.2% [frozen] vs. 4.6% [fresh], aRR 1.42, 95% CI 1.1-1.83). This finding remained true when the analysis was restricted to singleton gestations only for both groups: autologous (17.3% [frozen] vs. 7.1% [fresh], aRR 2.77, 95% CI 1.74-4.42) and donor oocytes (9.4% [frozen] vs. 7.8% [fresh], aRR 1.38, 95% CI 1.07-1.77). Additionally, we observed a decrease in LB (aRR 0.81, 95% CI 0.77-0.85); clinical pregnancy (aRR 0.83, 95% CI 0.8-0.87); and an increase in biochemical pregnancy loss (aRR 1.22, 95% CI 1.05-1.43) after the use of frozen oocytes in donors, but not autologous cycles.

Conclusions

Our findings of an increased incidence of high-birthweight infants after the transfer of embryos derived from frozen oocytes in both autologous and donor oocyte cycles raise questions about oocyte vitrification and deserve further study. Additionally, the finding of a decreased likelihood of LB with frozen-donor oocytes compared with fresh donor oocytes is an important finding, especially because more patients are seeking to use frozen oocytes in their donor egg cycles. Future research should be directed toward these findings to optimize the use of frozen oocytes in clinical practice.

Similar pregnancy outcomes from fresh and frozen donor oocytes transferred to gestational carriers: a SART database analysis isolating the effects of oocyte vitrification

PURPOSE

This work aimed to study clinical and neonatal outcomes of embryos derived from frozen compared to fresh donor oocytes in gestational carrier cycles.

METHODS

This is a retrospective cohort study using the Society for Assisted Reproductive Technology Clinic Outcome Reporting System database between 2014 and 2015, comprising of 1284 fresh transfer cycles to gestational carrier recipients of embryos resulting from fresh (n = 1119) and vitrified/thawed (n = 165) donor oocytes. Models were adjusted for gestational carrier age, preimplantation genetic testing (PGT-A), number of embryos transferred, multiple gestation, and fetal heart reduction. As our models were part of a larger analysis, intended parent BMI, smoking status, and parity were also adjusted for, but did not influence outcomes in this analysis.

RESULTS

There was no significant difference in probability of live birth rates when comparing embryos derived from fresh and frozen donor oocytes in gestational carrier cycles. There were also no significant differences in biochemical pregnancy losses or clinical miscarriage. There were no significant differences noted in low birthweight or high birthweight infants derived from fresh versus frozen donor oocyte after transfer into a gestational carrier.

CONCLUSIONS

The analysis of fresh and frozen donor oocytes in gestational carrier cycles provides the opportunity to assess for a possible effect of vitrification on the oocyte by controlling for differences in the uterine environment. We observed no significant differences in live birth, pregnancy loss, low birthweight or high birthweight infants when comparing fresh and frozen donor oocytes in gestational carrier cycles.

The impact of fresh versus frozen-thawed embryos on maternal serum analyte levels in IVF singleton and twin pregnancies

PURPOSE

To determine whether embryo cryopreservation is associated with a difference in maternal serum analyte levels in singleton and twin pregnancies conceived via in vitro fertilization (IVF).

METHODS

This was a retrospective cohort study of singleton and twin pregnancies conceived via IVF from a university health system from 01/2014 to 09/2019. Patients with available first and second trimester serum analyte data were included and analyzed separately. Multiple of the median (MoM) values for free β-human chorionic gonadotropin (β-hCG), pregnancy-associated plasma protein A, alpha-fetoprotein (AFP), Inhibin A, and unconjugated estriol (uE3) were compared between two groups: pregnancies conceived after the transfer of fresh embryos versus pregnancies conceived after the transfer of frozen-thawed embryos. Multiple linear regression of log MoM values with F test was performed to adjust for potential confounders.

RESULTS

For singletons, fresh embryos were associated with a lower median first trimester free β-hCG (1.00 MoM vs. 1.14 MoM; parameter estimate [PE] 0.90, 95% CI 0.82-0.99, p = .03) compared to frozen-thawed embryos. Fresh embryos were also associated with a lower median second trimester uE3 (0.93 MoM vs. 1.05 MoM; PE 0.88, CI 0.83-0.95, p = .0004) and AFP (1.02 MoM vs. 1.19 MoM; PE 0.91, CI 0.84-0.99, p = .02) compared to frozen-thawed embryos in singletons. There were no significant differences between median first and second trimester serum analytes in twin pregnancies compared between the two groups.

CONCLUSION

Singleton pregnancies derived from fresh embryos had lower first (free β-hCG) and second (uE3 and AFP) trimester analytes compared to frozen-thawed embryos. Twin pregnancies demonstrated no difference between the groups.

Current and future methods for embryo selection: on a quest for reliable strategies to reduce time to pregnancy

INTRODUCTION

The aim of this study was to analyze the usefulness of the principal embryological strategies to reduce time to pregnancy.

EVIDENCE ACQUISITION

A systematic search of publications in the PubMed/MEDLINE, Embase and Scopus databases from inception to present including "IVF," "blastocyst," "embryo colture," "competent embryo," "time to pregnancy," "aneuploid," "euploid," "vitrification," "preimplantation genetic," "IVF strategies" and "embryo selection" alone or in combinations has been done.

EVIDENCE SYNTHESIS

We have selected 230 articles and 9 of them have been included in this mini-review.

CONCLUSIONS

Several embryological strategies aimed to select the most competent embryo and reduce time to pregnancy have been proposed, even if few publications on this specific topic are available. preimplantation genetic testing (PGT-A) represents the unique method able to assess the embryonic chromosomal status, but this does not mean that PGT-A is a reliable strategy to reduce time to pregnancy. There is no consensus on a specific method to reduce time to pregnancy, nevertheless this final goal could be probably reached through a harmonious combination of procedures. Thus, a reliable strategy to reduce time to pregnancy could be achieved when embryo culture, embryo cryopreservation and PGT-A are perfectly integrated and appropriately offered to selected patients.

Pregnancies through oocyte donation. A mini review of pathways involved in placental dysfunction

Pregnancies resulting from assisted reproductive techniques (ART) are increasingly prevalent worldwide. While most pregnancies conceived through in-vitro fertilization (IVF) progress without complications, mounting evidence suggests that these pregnancies are at a heightened risk of adverse perinatal outcomes. Specifically, IVF pregnancies involving oocyte donation have garnered attention due to numerous reports indicating an elevated risk profile for pregnancy-related complications within this subgroup of patients. The precise mechanisms contributing to this increased risk of complications remain incompletely understood. Nonetheless, it is likely that they are mediated by an abnormal immune response at the fetal-maternal interface. Additionally, these outcomes may be influenced by baseline patient characteristics, such as the etiology of infertility, absence of corpus luteum, and variations in endometrial preparation protocols, among other factors. This review aims to succinctly summarize the most widely accepted mechanisms that potentially contribute to the onset of placental dysfunction in pregnancies conceived through oocyte donation.

Efficacy and safety of follitropin delta versus follitropin alpha/beta in infertility treatment: A systematic review and meta-analysis

Background

Follitropin δ may be an alternative to conventional follitropin α/β for controlled ovarian stimulation (COS) within assisted reproductive treatment (ART), but its efficacy and safety remain unknown. We performed a random-effects meta-analysis to compare the efficacy and safety of follitropin δ and follitropin α/β.

Methods

We searched randomized controlled trials comparing follitropin δ and follitropin α/β using MEDLINE, Embase, CENTRAL, ClinicalTrials.gov, and WHO-ITCRP on December 14, 2022. The primary outcomes were the live birth rate and the incidence of moderate or severe ovarian hyperstimulation syndrome (OHSS). The certainty of the evidence was assessed using the grading of recommendations assessment, development, and evaluation approach. The protocol was registered on the Open Science Framework.

Results

Three studies involving 2682 participants were included in our meta-analysis. The results indicated that follitropin δ may result in little to no difference in live birth rates (risk ratio [RR], 1.12; 95% confidence interval [CI], 0.91-1.38; low certainty) and the incidence of moderate or severe OHSS (RR, 0.78; 95% CI, 0.48-1.26; low certainty) compared with follitropin α/β.

Conclusion

Follitropin δ may result in little to no difference in COS compared with follitropin α/β, especially in terms of live births and safety.

Impact of Caesarean section on pregnancy outcomes in ART after transfer of one or more frozen blastocysts

INTRODUCTION

The prevalence of Caesarean delivery is rising steadily worldwide, and it is important to identify its future impact on fertility. A number of articles have been published on this subject, but the impact of Caesarean section on reproductive outcomes is still under debate, and none of these articles focus exclusively on frozen blastocysts.

OBJECTIVE

The aim of this study was to evaluate the impact of a previous Caesarean delivery compared with a previous vaginal delivery on the chances of a live birth following the transfer of one or more frozen embryos at the blastocyst stage.

METHODS

This was a retrospective, bicentric study at the University Hospitals of Nîmes and Montpellier, conducted between January 1st, 2016 and February 1st, 2021. Three hundred and ninety women with a history of childbirth and a transfer of one or more frozen embryos at blastocyst stage were included in the analysis. The primary outcome was the number of live births. Secondary outcomes were: the rate of positive HCG, miscarriage, ectopic pregnancy and clinical pregnancy, as well as the live birth rate according to the presence or absence of an isthmocele.

RESULTS

Of the 390 patients included, 118 had a previous Caesarean delivery and 272 a vaginal delivery. No statistically significant differences were found for the primary (p = 0.9) or secondary outcomes. A trend towards lower live birth rates was observed in patients with isthmoceles, but this did not reach significance (p>0.9). On the other hand, transfers were more often described as difficult in the Caesarean delivery group (p = 0.011).

CONCLUSION

Our study found no effect of previous Caesarean delivery on the chances of live birth after transferring one or more frozen blastocysts. However, further prospective studies are needed to confirm these results.

Polygenic embryo screening: are there potential maternal and fetal harms?

Polygenic embryo screening (PES) and its derivate the Embryo Health Score (EHS) have generated interest in both infertile and fertile populations due to their potential ability to select embryos with a reduced risk of disease and improved long-term health outcomes. Concerns have been raised regarding the potential harms of IVF itself, including possible epigenetic changes that may affect the health of the offspring in late adulthood, which are not fully captured in the EHS calculation. Knowledge of the potential impacts of the trophectoderm biopsy, which is a key component of the PES procedure, on the offsprings' health is limited by the heterogeneity of the population characteristics used in the published studies. Nonetheless, the literature suggests a possible increased risk of preterm delivery, birth defects and pre-eclampsia after trophectoderm biopsy. Overall, the risks of PES for prenatal and postnatal health remain uncertain, and further research is needed. Counselling patients regarding these risks before considering PES is important, to provide an understanding of the risks and benefits. This review aims to highlight some of these issues, the need for continued investigation in this area, and the importance of informed decision-making in the context of PES.

FSH administration at 12-hour intervals for the first 2 days, combined with mandatory GnRH-agonist trigger and blastocyst vitrification in women (<80Kg) with high AMH levels, results in higher cumulative live birth rates and is safer

We aimed to determine if a programme change to 12 hourly injections of FSH (150 IU per injection) for the first 2 days of stimulation in women with high ovarian reserve (AMH ≥ 30 pmol/L), followed by 24 hourly injections, would elicit increased earlier follicular recruitment, higher egg yields and blastocyst embryos for cryopreservation, leading to potential higher cumulative pregnancy rates, than conventional daily injections throughout. For safety reasons, the approach required mandatory cryopreservation of all blastocysts (mFET group; n = 74), after ovulation trigger with GnRH-agonist, in GnRH-antagonist controlled cycles. The 'Comparator group' (n = 91) comprised women with the same high AMH levels treated with the same base dose of FSH, with the aim of fresh blastocyst transfer and cryopreservation of supernumerary embryos, treated over the preceding 2 years. There was no difference in age, AMH, weight or BMI between the groups. The mFET group achieved higher egg (17.7 versus 11.7; p < 0.001) and embryo (10.9 versus 7.2; p < 0.001) yields and fewer cases with sub-optimal embryo yields (7% versus 22%; p = 0.018). The cumulative live birth rate was superior in the mFET group (73% versus 43%), as was the safety profile, and negligible rate of treatment plan modification.

Clinical outcomes after fresh versus frozen embryo transfer in women with advanced reproductive age undergoing in vitro fertilization: a propensity score-matched cohort study

This retrospective cohort study aimed to compare clinical outcomes following fresh or frozen embryo transfer (FET) in women with advanced reproductive age (ARA). Women aged 35-45 years who underwent their first autologous fresh or frozen cleavage stage embryo transfer cycle in the Centre for Assisted Reproduction of Shanghai First Maternity and Infant Hospital between January 2016 and December 2020 were included. The primary outcome was live birth after the first embryo transfer of the in vitro fertilization (IVF) cycle. Multiple covariates were used for propensity score matching (PSM) and generalized estimating equations were performed to examine the independent association between FET and live birth. Of the total 1453 patients, 327 patients had FET and 1126 patients had fresh ET. After the PSM procedure, 274 patients were included in each group. The live birth rate was 24.8% in the FET group and 25.2% in the fresh ET group (OR 0.98, 95% CI: 0.67-1.44, P = 0.92). Other pregnancy, perinatal and neonatal outcomes were all comparable between the two groups. This study showed that FET did not improve live birth and other clinical outcomes as compared with fresh embryo transfer in women with ARA who underwent their first IVF cycle.

Comparing the occurrence rate of gestational hypertension during pregnancy with frozen embryo transfer and natural pregnancy

Introduction

Recent researches have indicated that pregnancies with frozen embryo transfer are associated with the increment of risk of maternal and neonatal complications, especially hypertension during pregnancy. The present study aimed to compare the occurrence rate of gestational hypertension in pregnancy with frozen embryo transfer and normal pregnancy.

Materials and Methods

This research, as a retrospective cross-sectional study, was performed on pregnant women with frozen embryo transfer (n = 97) and women with normal pregnancies (n = 164) referring to medical centers under the supervision of Ahvaz University of Medical Sciences in 2021. Women aged 18-35 were included in the study after week 20th of pregnancy. Maternal and neonatal outcomes including hypertensive disorders of pregnancy (including gestational hypertension and preeclampsia), preterm birth (before the week 37th), low birth weight (lower than 2500 g), neonatal asphyxia (Apgar score >7 in minute 5th), intrauterine growth restriction (IUGR) and bleeding in the first trimester of pregnancy were evaluated. The association between frozen embryo transfer and pregnancy outcomes was evaluated using multiple logistic regressions.

Results

The findings of this study indicated that pregnancy hypertension was observed in 23 people (23.7%) from the frozen embryo transfer group vs. 18 people (11.0%) from the normal pregnancy group (P = 0.006). Frozen embryo transfer pregnancy has a higher risk of gestational hypertension (OR = 2.521, 95% CI: 1.281-4.962; P = 0.007), preterm birth (OR = 2.264, 95% CI: 1.335-3.840; P = 0.002), and low birth weight (OR = 2.017, 95% CI: 1.178-3.455; P = 0.011). However, the incidence of birth asphyxia (P = 0.850), intrauterine growth restriction (P = 0.068), first-trimester bleeding (P = 0.809), and placenta accreta (P = 0.143) did not show a significant difference between two types of normal pregnancy and frozen embryo transfer pregnancy.

Conclusion

Frozen embryo transfer pregnancy was associated with a higher risk of maternal and neonatal complications, hypertension, preterm birth, and low birth weight compared to natural and spontaneous pregnancies.

Impacts of different culture times on pregnancy outcomes after thawing of cleavage stage embryos

OBJECTIVE

This study assessed the impacts of in vitro culture times of cleavage embryos on clinical pregnancy outcomes.

METHODS

This retrospective cohort study was performed at the Reproductive Medicine Department of Hainan Modern Women and Children's Hospital in China between January 2018 and December 2022. Patients who first underwent frozen embryo transfer with in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles on day 3 were included. According to the time of embryo culture after thawing, the embryos were divided into long-term culture group(18-20 h) and short-term culture group (2-4 h). The clinical pregnancy rate was regarded as he primary outcome. To minimize confounding factors and reduce selection bias, the propensity score matching was used to balance the effects of known confounding factors and to reduce selection bias. Stratified analyses and multiple logistic regression analyses were used to evaluate the risk factors affecting the clinical pregnancy outcomes after matching.

RESULTS

General characteristics between two groups were comparable after matching. In the long-term culture group, 266/381 (69.81%) embryos had more than 10 blastomeres, and 75/381 (19.68%) reached the morula stage. After overnight culture, the implantation rate (27.97% vs. 14.28%, P = 0.018) and clinical pregnancy rate (38.46% vs. 22.5%, P = 0.05) were increased in the group with proliferating blastomeres. The long-term culture group trended to have a higher clinical pregnancy rate compared with the short-term culture group (35.74% vs. 29.79%). No statistical differences in clinical pregnancy outcomes between the two groups were observed after matching, including the rates of implantation (25.46% vs23.98%), miscarriages (25% vs. 22.85%), ongoing pregnancy rate (76.2% vs. 77.15%) and live birth rate (26.8% vs. 22.98%). Stratified analyses were performed according to the age of the patients. After matching, there were no significant differences in the clinical pregnancy, implantation and miscarriage rates between the two groups for patients > 35 or ≤ 35 years of age. Subgroup analyses were performed according to the quality of the transferred embryos. There were no significant differences in the clinical outcomes, between two groups after embryos transferred with the same quality. Multivariate Logistic regression analysis was used to evaluate the influencing factors of clinical pregnancy outcomes after matching. Culture time was not found to be an independent predictor for clinical pregnancy [OR 0.742, 95%CI 0.487 ~ 1.13; P = 0.165]. The age of oocyte retrieval [OR 0.906, 95%CI 0.865 ~ 0.949; P <0.001] and the number of high-quality embryos transferred [OR 1.787, 95%CI 1.256 ~ 2.543; P = 0.001] were independent factors affecting clinical pregnancy outcomes.

CONCLUSIONS

In vitro 18-20 h culture of embryos with either good-or non-good-quality will not adversely affect the clinical pregnancy.

Psychosocial wellbeing shortly after allocation to a freeze-all strategy compared with a fresh transfer strategy in women and men: a sub-study of a randomized controlled trial

STUDY QUESTION

Is the psychosocial wellbeing affected in women and men shortly after allocation to a freeze-all strategy with postponement of embryo transfer compared to a fresh transfer strategy?

SUMMARY ANSWER

In general, psychosocial wellbeing (i.e. emotional reactions to the treatment, quality-of-life, infertility-related stress, and marital benefit) was similar in women and men allocated to a freeze-all versus those allocated to a fresh-transfer strategy 6 days after disclosure of treatment strategy (i.e. 4 days after oocyte retrieval), although women in the freeze-all group reported a slightly higher degree of depressive symptoms and mood swings compared to women in the fresh transfer group.

WHAT IS KNOWN ALREADY

The use of a freeze-all strategy, i.e. freezing of the entire embryo cohort followed by elective frozen embryo transfer in subsequent cycles has increased steadily over the past decade in assisted reproductive technology (ART). This strategy essentially eliminates the risk of ovarian hyperstimulation syndrome and has proven beneficial regarding some reproductive outcomes in subgroups of women. However, patients experience a longer time interval between oocyte retrieval and embryo transfer, hence a longer time to pregnancy, possibly adding additional stress to the ART treatment. So far, little focus has been on the possible psychosocial strains caused by postponement of embryo transfer.

STUDY DESIGN, SIZE, DURATION

This is a self-reported questionnaire based sub-study of a multicentre randomized controlled trial (RCT) including 460 women and 396 male partners initiating their first, second, or third treatment cycle of invitro fertilisation or intracytoplasmic sperm injection (ICSI) from May 2016 to September 2018. This sub-study was included in the primary project protocol and project plan for the RCT, as psychosocial wellbeing was considered a secondary outcome.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women from eight public fertility clinics in Denmark and Sweden and one private clinic in Spain were randomized in a 1:1 ratio on the day of inclusion (menstrual cycle day 2 or 3) to either a freeze-all strategy with postponement of embryo transfer to a subsequent modified natural menstrual cycle or a fresh transfer strategy with embryo transfer in the hormone stimulated cycle. Treatment allocation was blinded until the day of the ovulation trigger. Women and their male partners were asked to complete a validated self-reported questionnaire 6 days after unblinding of treatment group allocation, corresponding to 4 days after oocyte retrieval, investigating their psychosocial wellbeing related to the treatment defined as emotional reactions to the treatment, quality-of-life, infertility-related stress, and marital benefit. The questionnaire included items from the Copenhagen Multi-Centre Psychosocial Infertility (COMPI) Fertility Problem Stress Scales and the COMPI Marital Benefit Measure.

MAIN RESULTS AND THE ROLE OF CHANCE

Baseline characteristics were comparable between the two groups for both women and men. In total, response rates were 90.7% for women and 90.2% for men. In the freeze-all group, 207 women and 179 men completed the questionnaire compared with 204 women and 178 men in the fresh transfer group. Men in the two treatment groups did not differ in any of the explored aspects of psychosocial wellbeing (i.e. emotional reactions to the treatment, quality-of-life, infertility-related stress, and marital benefit) 6 days after disclosure of treatment strategy. Women in the freeze-all group reported a slightly higher degree of depressive symptoms (P = 0.045) and mood swings (P = 0.001) (i.e. variables included in 'emotional reactions to treatment') compared to women in the fresh transfer group. When adjusted for multiple testing, depressive symptoms were no longer significantly different between the two groups. No additional differences in psychosocial wellbeing were found. Self-reported quality-of-life during treatment was also rated as similar between the two groups in both women and men, but was slightly lower than they would rate their quality-of-life when not in fertility treatment.

LIMITATIONS, REASONS FOR CAUTION

Although response rates were high, selection bias cannot be excluded. As this study was an RCT, we assume that psychosocial characteristics of the participants were equally distributed in the two groups, thus it is unlikely that the identified psychosocial differences between the freeze-all and fresh transfer group were present already at baseline. Furthermore, the questionnaire was completed as a one-time assessment 4 days after oocyte retrieval, thus not reflecting the whole treatment process, whereas an assessment after the full completed treatment cycle is needed to draw firm conclusions about the psychosocial consequences of the whole waiting period. However, a question posted that late would be highly biased on whether or not a pregnancy had been achieved.

WIDER IMPLICATIONS OF THE FINDINGS

The results indicate that individuals in the freeze-all group exhibited slightly higher levels of depressive symptoms and mood swings compared to those in the fresh transfer group. Nevertheless, it is important to note that any worries related to potential emotional strains stemming from delaying embryo transfer should not overshadow the adoption of a freeze-all approach in cases where it is clinically recommended. As long as patients are provided with comprehensive information about the treatment strategy before initiating the process, it is worth emphasising that other aspects of psychosocial wellbeing were comparable between the two groups.

STUDY FUNDING/COMPETING INTEREST(S)

The study is part of the Reprounion collaborative study, co-financed by the European Union, Interreg V Öresund-Kattegat-Skagerrak. L.P. reports financial support from Merck A/S. H.S.N. reports grants from Freya Biosciences ApS, Ferring Pharmaceuticals, BioInnovation Institute, Ministry of Education, Novo Nordic Foundation, Augustinus Fonden, Oda og Hans Svenningsens Fond, Demant Fonden, Ole Kirks Fond and Independent Research Fund Denmark and personal fees from Ferring Pharmaceuticals, Merck A/S, Astra Zeneca, Cook Medical, IBSA Nordic and Gedeon Richter. H.S.N is founder and chairman of the Maternity Foundation and co-developed the Safe Delivery App (non-profit). N.C.F. reports grants from Gedeon Richter, Merck A/S, Cryos International and financial support from Ferring Pharmaceuticals, Merck A/S and Gedeon Richter. N.C.F. is chairman in the steering committee for the guideline groups for The Danish Fertility Society (non-profit). P.H. reports honoraria from Merch A/S, IBSA Nordic and Gedeon Richter. A.L.M.E. reports grants and financial support from Merck A/S and Gedeon Richter. A.P. reports grants from Gedeon Richter, Ferring Pharmaceuticals, Merck A/S and personal fees from Preglem S.A., Novo Nordic Foundation, Ferring Pharmaceuticals, Gedeon Richter, Cryos International, Merch A/S, Theramex and Organon and the lend of embryoscope to the institution from Gedeon Richter. All other authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov NCT02746562.

The HERA (Hyper-response Risk Assessment) Delphi consensus for the management of hyper-responders in in vitro fertilization

PURPOSE

To provide agreed-upon guidelines on the management of a hyper-responsive patient undergoing ovarian stimulation (OS) METHODS: A literature search was performed regarding the management of hyper-response to OS for assisted reproductive technology. A scientific committee consisting of 4 experts discussed, amended, and selected the final statements. A priori, it was decided that consensus would be reached when ≥66% of the participants agreed, and ≤3 rounds would be used to obtain this consensus. A total of 28/31 experts responded (selected for global coverage), anonymous to each other.

RESULTS

A total of 26/28 statements reached consensus. The most relevant are summarized here. The target number of oocytes to be collected in a stimulation cycle for IVF in an anticipated hyper-responder is 15-19 (89.3% consensus). For a potential hyper-responder, it is preferable to achieve a hyper-response and freeze all than aim for a fresh transfer (71.4% consensus). GnRH agonists should be avoided for pituitary suppression in anticipated hyper-responders performing IVF (96.4% consensus). The preferred starting dose in the first IVF stimulation cycle of an anticipated hyper-responder of average weight is 150 IU/day (82.1% consensus). ICoasting in order to decrease the risk of OHSS should not be used (89.7% consensus). Metformin should be added before/during ovarian stimulation to anticipated hyper-responders only if the patient has PCOS and is insulin resistant (82.1% consensus). In the case of a hyper-response, a dopaminergic agent should be used only if hCG will be used as a trigger (including dual/double trigger) with or without a fresh transfer (67.9% consensus). After using a GnRH agonist trigger due to a perceived risk of OHSS, luteal phase rescue with hCG and an attempt of a fresh transfer is discouraged regardless of the number of oocytes collected (72.4% consensus). The choice of the FET protocol is not influenced by the fact that the patient is a hyper-responder (82.8% consensus). In the cases of freeze all due to OHSS risk, a FET cycle can be performed in the immediate first menstrual cycle (92.9% consensus).

CONCLUSION

These guidelines for the management of hyper-response can be useful for tailoring patient care and for harmonizing future research.

Initiating luteal phase support with sc progesterone based on low serum progesterone on the transfer day in true natural cycle frozen embryo transfers

Introduction

Concerning contemporary in-vitro fertilisation (IVF) practice, the use of frozen embryo transfer (FET) cycles has become more common than fresh transfers. Natural cycle (NC), programmed artificial cycle and mild stimulation cycle are primary endometrium preparation cycles. Monitoring serum progesterone levels in FET cycles are in the scope of current research focus. Low progesterone levels on the day of embryo transfer is presumed to negatively affect pregnancy outcomes, while progesterone supplementation may improve pregnancy rates. The purpose of our trial is to evaluate whether initiating subcutaneous (SC) progesterone supplementation on the day of embryo transfer when serum progesterone levels are below 10 ng/mL in tNC-FET will result in pregnancy rates comparable to those of patients with sufficient serum progesterone.

Methods

Retrospective single centre study was conducted between August 2022 and April 2023 with 181 tNC-FETs. Patients were separated into groups according to serum progesterone concentrations (≥10 ng/mL and <10 ng/mL) on embryo transfer (ET) day. S.c progesterone (25 mg) was given on the day of ET when serum progesterone was <10 ng/mL, continuing until the 10th gestational week. Blood samples for pregnancy tests were collected 12 days after ET. Outcome parameters were pregnancy rate, clinical pregnancy rate (CPR), miscarriage rate, multiple pregnancy rate, biochemical pregnancy, and ongoing pregnancy rate (OPR).

Results

About half (49.7%) had adequate progesterone concentrations (≥10ng/mL) on ET day. There was no significant difference between the groups regarding positive pregnancy test, OPR, multiple pregnancies, and miscarriage rates (57.8% versus 52.7%; 34.4% versus 29.7%, 1.1% versus 2.2%; 7.8% versus 5.5%; respectively, for progesterone concentrations on ET day ≥10 ng/mL and <10 ng/mL). With 55.2% of transfers leading to clinical pregnancy, significant differences emerged in biochemical pregnancy and CPR (3.3% vs 12.1%, P=0.02; 54.4% vs 40.7%, P=0.03, for ≥10 ng/mL and <10 ng/mL progesterone concentrations on ET day).

Discussion

This study indicates that nearly half of the tNC-FETs may need luteal phase support due to low progesterone. However, 25 mc sc progesterone rescued the luteal support and yielded similar OPR as compared to normal progesterone group. Further studies are needed for understanding optimal progesterone levels, supplementation effectiveness, and potential benefits of earlier supplementation in FETs.

Effect of comprehensive nursing intervention on the outcomes of in vitro fertilization in patients with polycystic ovary syndrome: A randomized controlled study

OBJECTIVE

To explore the effects of comprehensive nursing intervention on in vitro fertilization (IVF) and pregnancy outcomes in patients with polycystic ovary syndrome (PCOS).

METHOD

A total of 130 patients with PCOS admitted to our hospital from April 2021 to March 2023 were selected as the research subjects. They were evenly divided according to a random number table method. The control group received routine care for the patients, while the study group received comprehensive care for the patients. The IVF, pregnancy outcomes, negative emotional changes, serum and follicular fluid (FF) amyloid-related protein and C-reactive protein (CRP) levels of the 2 groups of patients were compared.

RESULT

The data on IVF rate and pregnancy rate in the study group were significantly better than those in the control group (P < .05). The SAS and SDS scores of the study group patients after intervention were significantly lower than those of the control group (P < .05). After intervention, the levels of serum and FF amyloid associated protein and CRP in the study group were significantly lower than those in the control group (P < .05).

CONCLUSION

Patients with PCOS who receive comprehensive care can increase their probability of IVF, improve their pregnancy outcomes, and have a positive significance in reducing negative emotions.

An appraisal of current embryo transfer strategies

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

Limited Effects of Ultra-low Oxygen Concentration during Extended Embryo Culture on In vitro Fertilisation Outcomes in Indian Women: A Retrospective Cross-sectional Study

Background

Amongst various other factors, oxygen (O2) concentration in embryo culture plays an important role in determining pregnancy outcomes in women undergoing in vitro fertilisation. Some studies have reported that lowering O2 levels in embryo culture provides better results.

Aims

To explore the effects of low- and ultra-low- O2 concentrations (5% and 2%, respectively) in extended embryo culture on various outcome parameters of pregnancy.

Settings and Design

This was a retrospective cross-sectional study.

Materials and Methods

In this study 382 participants had their embryos cultured in varying O2 concentrations (5% or 2%), followed by either a fresh embryo transfer (ET) or frozen embryo transfer (FET). Outcomes such as pregnancy rate, implantation rate, abortion rate, twinning rate, and live birth rate were compared between the groups.

Statistical Analysis Used

Chi square test was applied to compare the primary and secondary outcomes between different groups.

Results

No significant differences were observed in pregnancy rate and implantation rate between 5% and 2% O2 groups, irrespective of their mode of ET. The abortion rate was significantly higher in 5% O2 group than in 2% group during FET (24.71% vs. 11.49%, P = 0.02). While the proportion of good-quality embryos was higher in 5% O2 group, these did not translate to better pregnancy outcomes. Additionally, embryos cultured in 2% O2 concentration had a significantly better implantation rate when they were transferred fresh rather than frozen (71.34% vs. 61.46%, P = 0.04). There were no other differences observed.

Conclusion

Only marginal benefits were observed in switching human embryos to ultra-low O2 concentration after the initial days of culture.

Association between ambient air pollutants and birthweight of singletons following assisted reproductive technologies

OBJECTIVE

To investigate the associations between exposure to ambient air pollutants and birthweight following ART treatment.

DESIGN

Retrospective cohort study.

METHODS

We included 11,599 singletons derived from fresh cycles or frozen-thawed embryo transfer (FET) cycles between Jan 2013 and Dec 2019. Exposure to six air pollutants (SO2, NO2, CO, O3, PM2.5, and PM10) at patients` residences and the clinic site were estimated using the inverse distance weighting interpolation method based on data obtained from monitor sites. The daily mean levels of pollutants were estimated in potential exposure windows (the period from three months before treatment to oocyte retrieval, the period of ovarian stimulation, the period of in vitro culture, the period from embryo transfer to hCG test, the period of entire pregnancy, the 1st, 2nd, and 3rd trimester) were calculated. Generalized additive models adjusted for confounders including maternal age, BMI, and parity were used to evaluate the association between exposures and birthweight. Interaction of exposures and ART-associated factors, such as supraphysiologic estradiol and frozen-thawed, were explored in an XGboost model.

MAIN OUTCOME MEASURES

Birthweight and z-score of singletons.

RESULTS

In fresh cycles, O3 exposure during the period from three months before treatment to oocyte retrieval and SO2 exposure during in vitro culture at the ART clinic showed a linear association with birthweight (7.24, 95% CI: 1.18-13.31 g per 10 μg/m3 increase in O3; 25.92, 95% CI: 8.26-43.58 g per 10 μg/m3 increase in SO2, respectively). For patients receiving single blastocyst transfer with exposures below the China standard of 20 μg/m3, an increase of 10 μg/m3 in SO2 was associated with a 61.52 (95% CI: 1.13-121.91) g increase in birthweight. In FET cycles, no significant association was found between air pollution and birthweight. XGboost model did not reveal a strong interaction between the exposures and ART-related factors, except for the interactions between O3 exposure and BMI. However, none of the interactions reached a higher rank of importance.

CONCLUSIONS

Air pollution exposure during ART treatment may affect the birthweight of the offspring.

Exploring the Impact of Controlled Ovarian Stimulation and Non-Invasive Oocyte Assessment in ART Treatments

Invasive and noninvasive features are normally applied to select developmentally competent oocytes and embryos that can increase the take-home baby rates in assisted reproductive technology. The noninvasive approach mainly applied to determine oocyte and embryo competence has been, since the early days of IVF, the morphological evaluation of the mature cumulus-oocyte complex at the time of pickup, first polar body, zona pellucida thickness, perivitelline space and cytoplasm appearance. Morphological evaluation of oocyte quality is one of the options used to predict successful fertilization, early embryo development, uterine implantation and the capacity of an embryo to generate a healthy pregnancy to term. Thus, this paper aims to provide an analytical revision of the current literature relating to the correlation between ovarian stimulation procedures and oocyte/embryo quality. In detail, several aspects of oocyte quality such as morphological features, oocyte competence and its surrounding environment will be discussed. In addition, the main noninvasive features as well as novel approaches to biomechanical parameters of oocytes that might be correlated with the competence of embryos to produce a healthy pregnancy and live birth will be illustrated.

Killer Cell Immunoglobulin-like Receptor Genotypes and Reproductive Outcomes in a Group of Infertile Women: A Romanian Study

A growing body of evidence suggests that endometrial immune disorders may be responsible for endometrial dysfunctions that can lead to gynecological and obstetrical pathology. The aim of this study was to explore the potential relationship between different killer cell immunoglobulin-like receptor (KIR) genotypes and reproductive outcomes. We conducted a prospective cohort study that included 104 infertile patients undergoing an in vitro fertilization procedure. All participants underwent clinical and ultrasound examination, genetic evaluation (KIR genotyping), endometrial washing fluid sampling for cytokine determination, endometrial tissue sampling for histologic assessment and hysteroscopic evaluation. Our analysis showed statistically significant lower levels of uterine cytokines TNF-α (p = 0.001) and IL-1beta (p = 0.000) in the KIR AA genotype group as compared to KIR AB and BB among study participants with chronic endometritis. The study results suggest that the KIR AA genotype population subgroups may be more susceptible to developing endometrial disorders such as chronic endometritis. The changes in the behavior of NK cells seem to be subtle and expressed as an altered regulatory pattern.

Double vitrification and warming does not compromise the chance of live birth after single unbiopsied blastocyst transfer

STUDY QUESTION

Does double vitrification and thawing of an embryo compromise the chance of live birth after a single blastocyst transfer?

SUMMARY ANSWER

The live birth rate (LBR) obtained after double vitrification was comparable to that obtained after single vitrification.

WHAT IS KNOWN ALREADY

Double vitrification-warming (DVW) is commonly practiced to accommodate surplus viable embryos suitable for transfer, to allow retesting of inconclusively diagnosed blastocysts in preimplantation genetic testing (PGT), and to circumvent limitations associated with national policies on embryo culture in certain countries. Despite its popularity, the evidence concerning the impact of DVW practice on ART outcomes is limited and lacking credibility. This is the first thorough investigation of clinical pregnancy and LBR following DVW in the case where the first round of vitrification occurred at the zygote stage and the second round occurred at the blastocyst stage in the absence of biopsy.

STUDY DESIGN SIZE DURATION

This is a retrospective observational analysis of n = 407 single blastocyst transfers whereby embryos created by IVF/ICSI were vitrified-warmed once (single vitrification-warming (SVW) n = 310) or twice (DVW, n = 97) between January 2017 and December 2021.

PARTICIPANTS/MATERIALS SETTING METHODS

In the SVW group, blastocysts were vitrified on Day 5/6 and warmed on the day of embryo transfer (ET). In the DVW group, two pronuclear (2PN) zygotes were first vitrified-warmed and then re-vitrified on Day 5/6 and warmed on the day of ET. Exclusion criteria were ETs from PGT and vitrified-warmed oocyte cycles. All of the ETs were single blastocyst transfers performed at the University Hospital Zurich in Switzerland following natural or artificial endometrial preparation.

MAIN RESULTS AND THE ROLE OF CHANCE

The biochemical pregnancy rate, clinical pregnancy rate (CPR), and LBR were all comparable between the DVW and SVW groups. The CPR for DVW was 44.3% and for SVW it was 42.3% (P = 0.719). The LBR for DVW was 30.9% and for SVW it was 28.7% (P = 0.675). The miscarriage rate was additionally similar between the groups: 27.9% for DVW and 32.1% for SVW groups (P = 0.765).

LIMITATIONS REASONS FOR CAUTION

The study is limited by its retrospective nature. Caution should be taken concerning interpretation of these findings in cases where DVW occurs at different stages of embryo development.

WIDER IMPLICATIONS OF THE FINDINGS

The result of the present study on DVW procedure provides a framework for counselling couples on their chance of clinical pregnancy per warming cycle. It additionally provides confidence and reassurance to laboratory professionals in certain countries where national policies limit embryo culture strategies making DVW inevitable.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the University Research Priority Program 'Human Reproduction Reloaded' of the University of Zurich. The authors have no conflict of interest related to this study to declare.

TRIAL REGISTRATION NUMBER

N/A.

The true natural cycle frozen embryo transfer - impact of patient and follicular phase characteristics on serum progesterone levels one day prior to warmed blastocyst transfer

BACKGROUND

In a true-natural cycle (t-NC), optimal progesterone (P4) output from the corpus luteum is crucial for establishing and maintaining an intrauterine pregnancy. In a previous retrospective study, low P4 levels (< 10 ng/mL) measured one day before warmed blastocyst transfer in t-NC were associated with significantly lower live-birth rates. In the current study, we aim to examine the relationship between patient, follicular-phase endocrine and ultrasonographic characteristics, and serum P4 levels one day prior to warmed blastocyst transfer in t-NC.

METHOD

178 consecutive women undergoing their first t-NC frozen embryo transfer (FET) between July 2017-August 2022 were included. Following serial ultrasonographic and endocrine monitoring, ovulation was documented by follicular collapse. Luteinized unruptured follicle (LUF) was diagnosed when there was no follicular collapse despite luteinizing-hormone surge (> 17 IU/L) and increased serum P4 (> 1.5 ng/mL). FET was scheduled on follicular collapse + 5 or LH surge + 6 in LUF cycles. Primary outcome was serum P4 on FET - 1.

RESULTS

Among the 178 patients, 86% (n = 153) experienced follicular collapse, while 14% (n = 25) had LUF. On FET-1, the median serum luteal P4 level was 12.9 ng/mL (IQR: 9.3-17.2), ranging from 1.8 to 34.4 ng/mL. Linear stepwise regression revealed a negative correlation between body mass index (BMI) and LUF, and a positive correlation between follicular phase peak-E2 and peak-P4 levels with P4 levels on FET-1. The ROC curve analyses to predict < 9.3 ng/mL (< 25th percentile) P4 levels on FET-1 day showed AUC of 0.70 (95%CI 0.61-0.79) for BMI (cut-off: 23.85 kg/m2), 0.71 (95%CI 0.61-0.80) for follicular phase peak-P4 levels (cut-off: 0.87 ng/mL), and 0.68 (95%CI 0.59-0.77) for follicular phase peak-E2 levels (cut-off: 290.5 pg/mL). Combining all four independent parameters yielded an AUC of 0.80 (95%CI 0.72-0.88). The adjusted-odds ratio for having < 9.3 ng/mL P4 levels on FET-1 day for patients with LUF compared to those with follicle collapse was 4.97 (95%CI 1.66-14.94).

CONCLUSION

The BMI, LUF, peak-E2, and peak-P4 levels are independent predictors of low serum P4 levels on FET-1 (< 25th percentile; <9.3 ng/ml) in t-NC FET cycles. Recognition of risk factors for low serum P4 on FET-1 may permit a personalized approach for LPS in t-NC FET to maximize reproductive outcomes.

Young women were associated with higher risk of hypertensive disorders of pregnancy and cesarean section from hormone replaced cycles in frozen-thawed embryo transfer: a retrospective study of 5316 singleton deliveries

Background

The utilization of frozen-thawed embryo transfer (FET) cycles has been linked to heightened risks of adverse perinatal outcomes. However, the potential association between adverse perinatal outcomes and distinct endometrial preparation regimens remains unclear. Therefore, we aim to investigate the maternal and neonatal outcomes after hormone replacement treatment (HRT) cycles, natural cycles (NC) and HRT cycles with pretreatment using GnRHa (HRT + GnRHa) for ovulatory women undergoing FET cycles.

Methods

A large sample retrospective cohort study was carried out from 2016 to 2020. The data included a total of 5316 women who had singleton deliveries undergoing FET cycles and which were divided into three groups based on different endometrial preparation protocols: 4399 patients in HRT groups, 621 in GnRHa+HRT groups, 296 in NC groups. The outcomes consisted of maternal outcomes (cesarean section, hypertensive disorders of pregnancy (HDP), placenta previa, gestational diabetes mellitus (GDM));and neonatal outcomes (preterm birth, newborn birthweight, low birthweight, small for gestational age (SGA), macrosomia, large for gestational age (LGA), fetal malformation).

Results

After adjusting for a series of confounding variables, we found an increased risk of HDP (aOR=3.362; 95%CI, 1.059-10.675) and cesarean section (aOR=1.838; 95%CI, 1.333-2.535) in HRT cycles compared with NC, especially for ovulatory women under 35 years old. However, in all three groups, newborn birth weight was not significantly different. Meanwhile, perinatal outcomes did not differ significantly in terms of perinatal outcomes in HRT +GnRHa cycles compared with HRT cycles solely.

Conclusion

During FET cycles, singletons from HRT were related to higher risks of HDP and cesarean section, particularly for young women. GnRHa pretreatment didn't bring any benefit to perinatal outcomes compared with HRT cycles alone. Therefore, the natural cycle may be a more appropriate and safer option for young ovulatory women.

Oocyte and embryo cryopreservation in assisted reproductive technology: past achievements and current challenges

Cryopreservation has revolutionized the treatment of infertility and fertility preservation. This review summarizes the milestones that paved the way to the current routinary clinical implementation of this game-changing practice in assisted reproductive technology. Still, evidence to support "the best practice" in cryopreservation is controversial and several protocol adaptations exist that were described and compared here, such as cumulus-intact vs. cumulus-free oocyte cryopreservation, artificial collapse, assisted hatching, closed vs. open carriers, and others. A last matter of concern is whether cryostorage duration may impact oocyte/embryo competence, but the current body of evidence in this regard is reassuring. From social and clinical perspectives, oocyte and embryo cryopreservation has evolved from an afterthought when assisted reproduction was intended for immediate pregnancy with supernumerary embryos of secondary interest to its current purpose, which primarily is to preserve fertility long-term and more comprehensively allow for family planning. However, the initial consenting process, which still is geared to short-term fertility care, may no longer be relevant when the individuals that initially preserved the tissues have completed their reproductive journey. A more encompassing counseling model is required to address changing patient values over time.

Comparison of the efficacy of subcutaneous versus vaginal progesterone using a rescue protocol in vitrified blastocyst transfer cycles

RESEARCH QUESTION

Does administration of subcutaneous (s.c.) progesterone support ongoing pregnancy rates (OPR) similar to vaginal progesterone using a rescue protocol in hormone replacement therapy frozen embryo transfer cycles?

DESIGN

Retrospective cohort study. Two sequential cohorts - vaginal progesterone gel (December 2019-October 2021; n=474) and s.c. progesterone (November 2021-November 2022; n=249) -were compared. Following oestrogen priming, s.c. progesterone 25 mg twice daily (b.d.) or vaginal progesterone gel 90 mg b.d. was administered. Serum progesterone was measured 1 day prior to warmed blastocyst transfer (i.e. day 5 of progesterone administration). In patients with serum progesterone concentrations <8.75 ng/ml, additional s.c. progesterone (rescue protocol; 25 mg) was provided.

RESULTS

In the vaginal progesterone gel group, 15.8% of patients had serum progesterone <8.75 ng/ml and received the rescue protocol, whereas no patients in the s.c. progesterone group received the rescue protocol. OPR, along with positive pregnancy and clinical pregnancy rates, were comparable between the s.c. progesterone group without the rescue protocol and the vaginal progesterone gel group with the rescue protocol. After the rescue protocol, the route of progesterone administration was not a significant predictor of ongoing pregnancy. The impact of different serum progesterone concentrations on reproductive outcomes was evaluated by percentile (<10th, 10-49th, 50-90th and >90th percentiles), taking the >90th percentile as the reference subgroup. In both the vaginal progesterone gel group and the s.c. progesterone group, all serum progesterone percentile subgroups had similar OPR.

CONCLUSIONS

Subcutaneous progesterone 25 mg b.d. secures serum progesterone >8.75 ng/ml, whereas additional exogenous progesterone (rescue protocol) was needed in 15.8% of patients who received vaginal progesterone. The s.c. and vaginal progesterone routes, with the rescue protocol if needed, yield comparable OPR.

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.