High-quality Blastocysts Research Articles

CHK1 controls zygote pronuclear envelope breakdown by regulating F-actin through interacting with MICAL3

CHK1 mutations could cause human zygote arrest at the pronuclei stage, a phenomenon that is not well understood at the molecular level. In this study, we conducted experiments where pre-pronuclei from zygotes with CHK1 mutation were transferred into the cytoplasm of normal enucleated fertilized eggs. This approach rescued the zygote arrest caused by the mutation, resulting in the production of a high-quality blastocyst. This suggests that CHK1 dysfunction primarily disrupts crucial biological processes occurring in the cytoplasm. Further investigation reveals that CHK1 mutants have an impact on the F-actin meshwork, leading to disturbances in pronuclear envelope breakdown. Through co-immunoprecipitation and mass spectrometry analysis of around 6000 mouse zygotes, we identified an interaction between CHK1 and MICAL3, a key regulator of F-actin disassembly. The gain-of-function mutants of CHK1 enhance their interaction with MICAL3 and increase MICAL3 enzymatic activity, resulting in excessive depolymerization of F-actin. These findings shed light on the regulatory mechanism behind pronuclear envelope breakdown during the transition from meiosis to the first mitosis in mammals.

Luteinizing hormone supplementation with human menopausal gonadotropin versus low dose human chorionic gonadotropin during ovarian stimulation does not affect live birth rates after fresh and frozen embryo transfer.

Luteinizing hormone (LH) plays an important role in ovarian follicle maturation. Human menopausal gonadotropin (hMG) or low dose human chorionic gonadotropin (hCG) can provide LH supplementation during in vitro fertilization (IVF) ovarian stimulation, though studies directly comparing their impact on IVF outcomes are limited. The aim of the study was to determine whether LH supplementation with hMG versus low dose hCG during IVF stimulation affects live birth rate. Fresh and frozen embryo transfers (ET) from 2017 to 2021 after standard long or antagonist protocols supplemented with hMG (75-250 IU) or low dose hCG (50-100 IU) during stimulation cycles in our academic center were included. Statistical analysis was performed with T-tests, Mann-Whitney U tests, Chi-square, and multiple linear and logistic regression. Four hundred and sixty eight unique stimulation cycles resulting in 213 fresh and 412 frozen embryo transfers were analyzed. There was a lower mature oocyte yield (10.9 vs. 11.8, p = 0.044) but similar high-quality blastocyst yield (3.6 vs. 3.9, p = 0.11) for hMG vs low dose hCG. Live birth rates per transfer were comparable for fresh (42% vs. 49%, p = 0.24) and frozen (46% vs. 53%, p = 0.45) embryo transfers. Multiple logistic regressions showed no association between supplemental gonadotropin and live birth for both fresh and frozen embryo transfers. Fresh and frozen IVF-ET pregnancy outcomes were comparable after hMG versus low dose hCG supplementation, suggesting flexibility in supplemental LH dosing regimens that may address patient or physician preference or cost concerns.

A new decision-support tool in a multi-center randomized trial for personalized, optimized, and simplified fertility treatment in non-PCOS patients.

This study aimed to evaluate the effectiveness of a clinical decision support tool, Opt-IVF, in achieving the following outcomes: reducing the total cumulative dosage of Gonadotropins (Gns) used during controlled ovarian stimulation cycles and reducing the repeated ultrasonograms (USG) for monitoring follicular growth without compromising the number of good quality blastocysts obtained. The study design employed a multi-center randomized trial. The study enrolled 115 women aged 25-45 years undergoing IVF. Among the participants, 55 were randomly assigned to the intervention group (Opt-IVF), and 60 were randomly assigned to the control group. The intervention involved using a clinical decision support tool, Opt-IVF, to guide Gn dosing and trigger dates. The participants in the intervention group required significantly lower cumulative Gn dosage. The intervention group had higher numbers of oocytes retrieved and M2 retrieved than the control group. The number of good-quality blastocysts, the good-quality blastocyst rate, the ovarian sensitivity index (OSI), and the pregnancy rate in the intervention group were significantly higher than in the control group. The utilization of the clinical decision support tool led to several positive outcomes, including eliminating the need for ultrasound exams after day 5, reducing the dosage of Gn required, and yielding significantly higher numbers of high-quality blastocysts and higher pregnancy rates. Thus, Opt-IVF can successfully provide a personalized, optimized, and simplified approach to superovulation. Opt-IVF consistently outperformed the clinical teams in most of the outcomes. Clinical trials registration: ClinicalTrials.gov (ID - NCT05811065). Date of Registration: 15 March 2023. Date of enrollment of the first subject: 20 March 2023. The high cost of IVF is a result of costly drugs, fixed prices for infrastructure, extensive testing required, and labor costs for physicians and other healthcare personnel. Superovulation, which involves the drug-induced release of multiple eggs needed for IVF, accounts for a significant share of these costs. Current approaches to superovulation involve almost daily monitoring of follicle development using ultrasound and/or blood tests. The daily dosage of stimulatory hormones is then prescribed by physicians based on empirical data and clinical experience. However, the dose is not optimized for each patient, and overstimulation complications can occur. The cost of testing and drugs makes this stage very expensive. To overcome the shortcomings of this system, we have developed a decision support tool (Opt-IVF) that can provide a personalized model-optimized dosage profile for each patient. The clinical results show that Opt-IVF optimizes and personalizes dosage, reduces testing, and provides better outcomes for patients.

Analysis of factors influencing pregnancy and its outcomes in women undergoing in vitro fertilization-embryo transfer/frozen embryo transfer cycles: A retrospective study.

The relationship between clinical outcomes and various factors influencing pregnancy was analyzed to provide reference data for patients and clinicians when selecting embryo transfer protocols. This was a retrospective study of 1309 transfer cycles between June 1, 2018, and May 1, 2023, in the Reproductive Medicine Center. Univariate analysis was performed on various factors that may have affected pregnancy outcomes, and further regression analysis was performed on those factors found by univariate analysis to correlate positively with clinical pregnancy outcomes. Finally, the embryo transfer schemes were compared based on the analysis results. The results showed that the stage of embryonic development significantly affected pregnancy outcomes after transplantation (P < .01, 95% confidence interval: 2.554 [1.958-3.332]). There was no significant difference in the pregnancy rate between 1 high-quality blastocyst transfer and 2 cleavage-stage embryos or blastocyst transfer (64.22% vs 70.11%, P = .439); however, the rate of multiple pregnancies after 1 high-quality blastocyst transfer was close to the rate of natural conception. These data show that the transfer of single high-quality blastocysts can significantly reduce the multiple pregnancy rate while ensuring an ideal pregnancy rate, which can be used as a reference for planning the first transplantation in patients with good prognoses.

What sperm parameters effect blastocyst formation and quality during ICSI with severe male infertility

Sperm-derived genetic material contributes half of the genome to the embryo, hence it’s crucial to investigate which sperm parameter influences blastocyst formation in the intracytoplasmic sperm injection (ICSI) cycles with severe male infertility. The retrospective study analyzed 296 ICSI cycles with severe oligoasthenoteratozoospermia (OAT) and 99 ICSI cycles with preimplantation genetic testing for aneuploidy (PGT-A). Following the correlation analysis, data stratifications were performed in the OAT ICSI subgroup. The results showed that the matching blastocyst in the OAT ICSI cycles had inferior sperm parameters. DFI and sperm morphology had an influence on the blastocyst formation rate and the high-quality blastocysts formation rate on Day6, but no significant effect on the blastocyst development on Day 5. The high-quality blastocysts formation rate and ratio of high-quality blastocyst on Day 6 were demonstrably better in the subgroup of the teratozoospermic morphology when DFI was within the normal range. In the case of the normal sperm morphology, no statistically significant difference was found in blastocyst development, although there were numerical differences within different DFI subgroups. It was concluded that the blastocyst quality and development declined with the decreased sperm qualities.

Precise hourly personalized embryo transfer significantly improves clinical outcomes in patients with repeated implantation failure.

This study investigated whether RNA-Seq-based endometrial receptivity test (rsERT)-which provides precision for the optimal hour of the window of implantation (WOI)-can improve clinical outcomes of frozen embryo transfer (FET) cycles in patients with a history of repeated implantation failure (RIF). Patients with a history of RIF who received at least one autologous high-quality blastocyst during the subsequent FET cycle were retrospectively enrolled and divided into two groups: rsERT and FET, comprising patients who underwent rsERT-guided pET (n=115) and standard FET without rsERT (n=272), respectively. In the rsERT group, 39.1% (45/115) of patients were receptive. rsERT patients showed a higher probability of achieving both positive human chorionic gonadotropin (63.5% vs. 51.5%, P=0.03) and clinical pregnancy (54.8% vs. 38.6%, P=0.003) rates. In subgroup analysis, rsERT patients with non-receptive results had higher clinical pregnancy rates than patients undergoing FET (58.6% vs. 38.6%, P=0.003). rsERT patients with receptive results guided by rsERT with a precise WOI time had higher, although non-significant, clinical pregnancy rates (48.9% vs. 38.6%, P=0.192) than patients who underwent standard-time FET. Hourly precise rsERT can significantly improve the probability of achieving clinical pregnancy in patients with RIF, especially in those with non-receptive rsERT results.

The construction of machine learning-based predictive models for high-quality embryo formation in poor ovarian response patients with progestin-primed ovarian stimulation

ObjectiveTo explore the optimal models for predicting the formation of high-quality embryos in Poor Ovarian Response (POR) Patients with Progestin-Primed Ovarian Stimulation (PPOS) using machine learning algorithms.MethodsA retrospective analysis was conducted on the clinical data of 4,216 POR cycles who underwent in vitro fertilization (IVF) / intracytoplasmic sperm injection (ICSI) at Sichuan Jinxin Xinan Women and Children’s Hospital from January 2015 to December 2021. Based on the presence of high-quality cleavage embryos 72 h post-fertilization, the samples were divided into the high-quality cleavage embryo group (N = 1950) and the non-high-quality cleavage embryo group (N = 2266). Additionally, based on whether high-quality blastocysts were observed following full blastocyst culture, the samples were categorized into the high-quality blastocyst group (N = 124) and the non-high-quality blastocyst group (N = 1800). The factors influencing the formation of high-quality embryos were analyzed using logistic regression. The predictive models based on machine learning methods were constructed and evaluated accordingly.ResultsDifferential analysis revealed that there are statistically significant differences in 14 factors between high-quality and non-high-quality cleavage embryos. Logistic regression analysis identified 14 factors as influential in forming high-quality cleavage embryos. In models excluding three variables (retrieved oocytes, MII oocytes, and 2PN fertilized oocytes), the XGBoost model performed slightly better (AUC = 0.672, 95% CI = 0.636–0.708). Conversely, in models including these three variables, the Random Forest model exhibited the best performance (AUC = 0.788, 95% CI = 0.759–0.818). In the analysis of high-quality blastocysts, significant differences were found in 17 factors. Logistic regression analysis indicated that 13 factors influence the formation of high-quality blastocysts. Including these variables in the predictive model, the XGBoost model showed the highest performance (AUC = 0.813, 95% CI = 0.741–0.884).ConclusionWe developed a predictive model for the formation of high-quality embryos using machine learning methods for patients with POR undergoing treatment with the PPOS protocol. This model can help infertility patients better understand the likelihood of forming high-quality embryos following treatment and help clinicians better understand and predict treatment outcomes, thus facilitating more targeted and effective interventions.

P-252 Non-invasive artificial intelligence (AI) prediction of blastocyst development from mature oocytes unveils correlation with blastocyst ploidy for enhanced reproductive insight at earliest stage of development

Abstract Study question Can MAGENTA identify mature oocytes more likely to develop into a blastocyst of euploid status? Summary answer Although built to predict blastocyst development, MAGENTA analysis of mature oocytes additionally displays the ability to highlight those with higher potential to become euploid embryos. What is known already MAGENTA (AI image-analysis tool) has been trained to assess and predict blastocyst stage embryo development from mature, denuded oocytes. MAGENTA scores consistently identify oocytes of better quality – more likely to develop into a blastocyst, including blastocysts of higher morphological quality. However, in addition to achieving a blastocyst, the ploidy status of that embryo is crucial in dictating overall chances of implantation and cycle success. Although MAGENTA was not trained to predict blastocyst ploidy from oocytes, most chromosomal errors are of maternal meiotic origin. A correlation between MAGENTA and ploidy status would ignite research possibilities and provide valuable insights. Study design, size, duration A retrospective dataset of 1,324 blastocyst embryos that underwent PGT-A via NGS sequencing, between the years 2021-2023, was assessed. All embryos that were tested for ploidy from a patient cohort were included. Embryos reported as mosaic or ‘no diagnosis’ were excluded from analysis (N = 169). All embryos were cultured in a time-lapse incubator immediately post-ICSI. Of the biopsied blastocysts, 81% were of good morphological quality (expansion grade 1-6, ICM and TE grade A/B). Participants/materials, setting, methods The data includes 292 patients with a mean age of 38.5 (range 19-46) and an average number of tested blastocysts of 4 (range 1-14). Of the 1173 blastocysts, 847 were aneuploid (72.2%) and 326 were euploid (27.8%). 83% of the blastocysts were from patients of advanced maternal age (AMA, ≥38years old). The first time-lapse image, capturing the mature oocyte stage, was extracted, and scored by MAGENTA (scale 0-10). MAGENTA scores were compared by Welch’s t-tests. Main results and the role of chance Impressively, oocytes that developed into euploid blastocysts (n = 326) were identified by MAGENTA with a higher average score of 6.8 compared to those that developed into aneuploid blastocysts (n = 847) with a score of 6.4; a statistically significant differentiation (p &amp;lt; 0.05). 80% of the dataset were high quality blastocysts (expansion 4-6, ICM and TE grade A/B) with an imbalance of euploid (n = 295; mean score 6.8) and aneuploid (n = 643; mean score 6.6) blastocysts—likely a result of AMA. Therefore, subgroup analysis was focused on assessing the ploidy status relationships amongst several patient age groups within these AMA cases. Due to our clinic’s indication for PGT-A, the smallest subset of oocytes was from patients &amp;lt;38 years of age (N = 373, 48% euploid). In this age group there was no significant difference in MAGENTA scores between the oocytes of euploid and aneuploid embryo status (6.9 vs 6.7; p = 0.522). However, in oocytes from patients aged ≥38 (N = 800, 19% euploid), the distinction between those that became euploid and aneuploid blastocysts is evident with a statistically significant difference in MAGENTA scores (6.8 vs 6.3; p &amp;lt; 0.05). This relationship with ploidy status additionally remains with further stratification into the ≥41 age group (N = 467 oocytes, 13% euploid; 6.7 vs 5.9; p &amp;lt; 0.01). Limitations, reasons for caution Majority of the patients in this dataset underwent PGT-A due to AMA, further research is required to include a wider age demographic, particularly in patients &amp;lt;35 years old. Greater representation of varying blastocyst qualities is required to further assess MAGENTA correlation to ploidy outcomes amongst quality groups. Wider implications of the findings This study presents the first non-invasive assessment of mature oocyte quality that indicates oocytes with greater potential for euploid blastocyst development. This application of MAGENTA provides a novel method of gaining ploidy status potential at the mature oocyte stage, which is invaluable to both IVF and cryopreservation cycles. Trial registration number NOT APPLICABLE

O-045 Does PGT improve outcomes in poor responders?

Abstract All studies randomizing women to undergo PGT-A or transfer of untested embryos are in patients with excellent blastocyst quality. No studies show that PGT-A improves live birth rate per stimulated cycle, only per embryo transfer in patients fortunate to have high quality blastocysts. There are also no randomized trials of cleavage stage vs blastocyst transfer in patients with fewer than 4 embryos. Normal babies have been reported after transfer of aneuploid (not only mosaic) embryos. Patients with decreased ovarian reserve have high chances of no embryo transfer and therefore no chance of pregnancy if they chose to undergo IVF with PGT-A.

P-065 HyperSperm, a new sperm preparation method for IVF/ICSI improves sperm capacitation while maintaining a high safety profile

Abstract Study question Does HyperSperm improve sperm capacitation without affecting sperm quality? Summary answer HyperSperm enhances sperm hyperactivated motility, a hallmark of capacitation, without compromising sperm viability, acrosome integrity, or DNA fragmentation. What is known already HyperSperm is a novel semen preparation method for IVF/ICSI based on mimicking effective capacitation that occurs in the female tract. HyperSperm, which consists of 3 media used sequentially to treat sperm before insemination, gave rise to more high-quality blastocysts compared to current standard of care in a pilot split oocyte study in 10 couples. Study design, size, duration This prospective in vitro study was conducted between July 2023 and January 2024 in an academic department. A consecutive cohort of 15 normozoospermic individuals were recruited and included. Each participant provided a semen sample by masturbation after written informed consent was obtained on the day of the collection. Participants/materials, setting, methods Semen samples from normozoospermic individuals (n = 15) were divided into two halves. After density gradient centrifugation, Control half was incubated in modified HTF (Human Tubal Fluid) for 2-4 hours, while the other half underwent HyperSperm treatment. The following parameters were assessed: sperm viability (eosin exclusion); motility and kinematic parameters (CASA); acrosome integrity (fluorescein-labeled Pisum sativum lectin staining); and DNA fragmentation by TUNEL. Differences between groups were evaluated by paired T-test. Significant differences were considered when p &amp;lt; 0.05. Main results and the role of chance Following treatments, sperm viability (90±3% Control vs. 91±3% HyperSperm) and motility (87±2% Control vs. 89±3% HyperSperm) were similar between groups (p &amp;gt; 0.05). Notably, HyperSperm induced a significant hyperactivation increase (9±2% Control vs. 22±3% HyperSperm), along with associated kinematic parameters (i.e., curvilinear velocity and lateral head displacement) (p &amp;lt; 0.05). Furthermore, HyperSperm treatment did not promote motility decrease over time. Finally, there were no differences in the percentage of sperm with intact acrosome (91±2% Control vs. 90±2% HyperSperm) and DNA fragmentation (3±1% Control vs. 3±1% HyperSperm) between groups (p &amp;gt; 0.05). Altogether, HyperSperm has shown to significantly improve sperm capacitation parameters while maintaining a high safety profile in the treated sample. Limitations, reasons for caution The study is limited to normozoospermic samples, and further research should validate these findings across broader male populations undergoing IVF/ICSI. Wider implications of the findings HyperSperm has demonstrated an increase in the production of high-quality blastocysts via IVF, that would reduce barriers to treatment access through higher cumulative success rates and lower treatment repetitions. The observed increase in hyperactivation combined with the safety profile of HyperSperm supports its potential for future adoption in reproductive clinics. Trial registration number not applicable

O-219 Explainable artificial intelligence (XAI) to determine the follicle sizes on trigger day that maximize mature oocyte yield

Abstract Study question Which follicle sizes on trigger day (TD) are key to obtaining mature oocytes, embryos, and blastocysts, thereby enhancing live birth rates? Summary answer Follicles sized 13-18mm are most likely to yield mature oocytes. Live birth rate (LBR) was increased with a greater proportion of follicles in this range. What is known already At the time of oocyte retrieval, follicles that are either too small or too large are less likely to yield mature oocytes. However, there is only limited data examining which follicle sizes on TD administration are optimally sized to yield mature oocytes, nor any data examining whether live birth rates are impacted. Explainable artificial intelligence (XAI) offers a valuable opportunity to leverage clinical data to determine the range of follicle sizes that are most likely to yield mature oocytes and lead to improved downstream outcomes. Study design, size, duration A retrospective study incorporating 19,082 patients undergoing their first IVF/ICSI cycle (2005-2023) across 11 European clinics. Follicle sizes on TD were related to oocyte maturity (14,140 patients), fertilization (17,822 patients), high-quality blastocyst development (17,488 patients), and pregnancy outcomes (12,672 patients). Secondary analyses included stratification by age (&amp;gt;35 years: 4,717 patients; ≤35 years: 5,707), and suppressant protocol (GnRH agonist: n = 5,420 patients; GnRH antagonist: n = 3,982). Participants/materials, setting, methods An ensemble-based XAI model, developed through ‘internal-external validation’, was trained, Bayesian optimized, and independently iteratively tested on hold-out clinic datasets. The model determined follicle sizes contributing most to successful laboratory outcomes by harnessing permutation importance and ‘SHAP’ values. Model performance was evaluated and optimized for mean absolute error (MAE). The top 50% contiguous cohort of influential follicle sizes on TD were identified, and further validated through analysis of follicle sizes on preceding days. Main results and the role of chance XAI analysis revealed that follicles sized 13-18mm on TD were most influential in yielding mature oocytes, especially those sized 15-18mm (MAE: 3.60 ±0.35). Predictive follicle sizes from scans 1-2 days preceding TD administration were consistent with expected mean follicle growth rates. For high-quality blastocysts, follicles sized 14-20mm were contributory, narrowing to 15-18mm in the subset of patients where oocytes had been confirmed to be mature. In hCG-triggered cycles, follicles sized 12-19mm were most likely to yield mature oocytes in GnRH antagonist cycles, whereas follicles sized 14-20mm were most contributory in GnRH agonist cycles. In patients ≤35 years, follicles 13-18mm were most contributory, whereas a wider range of follicles (11-20mm) were contributory in patients &amp;gt;35 years. In line with current practice, having three lead follicles ≥17mm on TD was associated with a median improvement in mature oocyte yield of 10% versus those that did not (p &amp;lt; 0.0001). By comparison, maximizing the proportion of follicles on TD within the optimal size range could better improve mature oocyte yield, for example, by 42% when at least 70% of follicles were sized 15-18mm (p &amp;lt; 0.0001). Likewise, LBR improved as the proportion of follicles sized 13-18mm was increased (&amp;lt;10%: 23.3%; 10-20%: 25.7%; 20-30%: 28.8%; 30-40%: 31.6%). Limitations, reasons for caution These data could help guide when to administer the trigger to optimize clinical outcomes, however prospective assessment of different TD strategies based on the proportion of follicles within the optimal follicle size ranges identified in comparison to current practice based on lead follicle size is required prior to clinical adoption. Wider implications of the findings These findings provide a data-driven approach to personalizing ovarian stimulation in IVF. The findings generated by applying an XAI model could assist clinicians in optimizing TD timing, potentially enhancing clinical outcomes by moving beyond the conventional focus on lead follicle size. Trial registration number not appicable

P-541 First live birth report of identical twins from a single low-grade mosaic blastocyst (46,XY/45,XY,-19) transfer: when a small chance becomes a double miracle

Abstract Study question N/A Summary answer First live birth report of identical twins from the transfer of a single low-grade mosaic blastocyst for monosomy on chromosome 19. What is known already The clinical decision-making in cases involving the transfer of low-grade mosaic embryos remains controversial. Recent studies have indicated that low-grade mosaic embryos exhibit pregnancy rates similar to euploid embryos, encouraging their transfer. However, the judgment to proceed in most cases is still challenging. The transfer of a low-grade mosaic embryo for monosomy on chromosome 19 is considered relative safe. The occurrence of human twins resulting from embryo splitting in ART (Assisted Reproductive Technology) cycles is a rare phenomenon. To date, there are no reports of the birth of identical twins from a single low-grade mosaic embryo transfer. Study design, size, duration This is a single-case report detailing an assisted reproduction cycle conducted by a couple. Participants/materials, setting, methods A couple with a nine-year history of infertility, characterized by low ovarian reserve and azoospermia, underwent an ICSI (Intracytoplasmic Sperm Injection) cycle in October 2022. Due to azoospermia, microsurgical epididymal sperm aspiration and subsequent freezing of the retrieved sperm were performed prior to ovum pick-up. PGT-A (Preimplantation Genetic Testing for Aneuploidy) of the resultant blastocysts was conducted, followed by the transfer of a single low-grade mosaic after a modified natural endometrial preparation cycle. Main results and the role of chance Seven mature oocytes were retrieved, and following ICSI with the thawed seminal sample, four blastocysts were developed and biopsied for PGT-A analysis. Out of these four high-quality blastocysts, three were aneuploid, and the remaining one was a low-grade (50%) mosaic for monosomy on chromosome 19. After genetic counselling, the patients decided to proceed with the transfer of a day 5 3AA low-grade mosaic embryo, which led to a successful pregnancy. The transferred embryo split, generating a pregnancy of identical twins. The twins were delivered via cesarean section at 30 weeks and 5 days of gestational age. The premature delivery was necessitated due to the mother developing cardiac insufficiency related to pre-existing valvulopathy and a superimposed venous thromboembolism. Peripheral blood samples from the twins have been collected for a 100-cell karyotype analysis (results will be available by February 9th). This case marks the first reported instance of twins born from the transfer of a single low-grade mosaic blastocyst (46,XY/45,XY,-19). Limitations, reasons for caution This is a retrospective case-report from one couple, describing a rare event. Wider implications of the findings This case-report could elucidate the physician’s decision and slightly encourage the transfer of low-grade mosaic embryos when there are no full euploids available. Trial registration number Not pllicable

O-028 DNA methylation testing with cervical secretion can serve as a non-invasive biomarker for predicting successful implantation in frozen-thawed embryo transfer

Abstract Study question Is cervical secretion gene methylation profile associated with embryo implantation outcome, and can be used as a non-invasive biomarker for pregnancy prediction in FET cycles? Summary answer Cervical secretion gene methylation profiles show significant associations with implantation outcomes, and can serve as a non-invasive predictor of successful pregnancy in FET cycles. What is known already Cause of implantation failure remains a black box in reproductive medicine, and the exact mechanism of how endometrial receptivity is still behind the curtain. Epigenetic modifications including DNA methylation regulate gene expression and may alter endometrium receptivity. Endometrial DNA methylation changes vigorously only during the reconstruction of a new endometrium throughout each menstrual cycle, suggesting a unique methylation landscape in each regenerated endometrium. Cervical secretions contain implantation-related cytokines and genetic material from endometrium, and the DNA methylation profiles of cervical secretions is highly correlated with endometrium. Therefore, cervical secretions can be used as non-invasive surrogates for investigating endometrial condition. Study design, size, duration This multi-centered, case-control study enrolled 72 infertile females who entered the FET cycle with at least one high-quality blastocyst available between Aug 2017 and Dec 2022. Embryos assessed by Gardner scoring system with grade 3BB or above were defined as high-quality. Cervical secretions were collected on the day right before embryo transfer, and then DNA methylation profile were assessed. Participants/materials, setting, methods These females aged between 20-45 years-old with regular menstruation cycle (24-35 days) and normal BMI (17.5–32.0 kg/m2). Uterine cavity lesions and hydrosalpinx without treatment, adenomyosis, large uterine myoma that distorted endometrium, and thin endometrium (&amp;lt;7mm) were excluded. The association between the cervical secretion gene methylation profile and pregnancy outcome was evaluated via quantitative methylation-specific PCR (qMSP), methylation array, and genome-wide analysis. Different machine learning algorithms were utilized for differential methylation analysis and implantation prediction. Main results and the role of chance Cervical secretion DNA methylome differed between receptive (pregnant) and non-receptive (non-pregnant) FET cycle with genome-wide methylation array. The accuracy of pregnancy outcome prediction using top 2000 differential methylation probes (DMPs) in promoter region can be as high as 86% in all tested sample and 96.4% in pregnant samples. Bioinformatic analysis of six selected candidate genes related to implantation from literature review showed significant differences in DNA methylation between receptive and non-receptive endometrium. The methylation level of the six candidate genes with eight regions were measured by the qMSP platform and showed varying degrees of differential methylation status between the pregnancy and non-pregnancy groups. The AUCs for a single gene/region ranged from 0.53–0.67 for implantation prediction. Ten different machine learning models were applied and the results showed that the combination of candidate genes’ DNA methylation profiles could differentiate pregnant from non-pregnant samples with an accuracy as high as 86.67% and an AUC of 0.81 by logistic regression model. The best model from different machine learning algorithms using selected DMPs of genes related to window of implantation (WOI) can predict ongoing pregnancy with accuracy rates as high as 86.78% and AUC values up to 0.91. Limitations, reasons for caution The results obtained from a relatively small cohort size, and the timing of sample collection is on the day right before embryo transfer. Further investigation of methylation profiles in late follicular phase along with large sample size with euploid embryo transfer are mandatory for validation and clinical applications. Wider implications of the findings We firstly demonstrated the feasibility of cervical secretion methylation profile as a non-invasive testing for pregnancy prediction. The promising result may contribute to predicting endometrial receptivity for cycles with a favorable endometrium and maximize the successful pregnancy rate of embryo transfer. Trial registration number not applicable

P-525 Is there an impact of chromosomal structural rearrangements on IVF laboratory outcomes in PGT-SR cycles? a propensity score matching-based study

Abstract Study question Are IVF laboratory outcomes altered in PGT-SR cycles, and how are these outcomes affected by the type of rearrangement and the carrier’s gender? Summary answer PGT-SR cycles showed a decrease in overall blastulation and top-quality blastocyst rates compared to PGT-A cycles. Transferable blastocyst rate correlates with chromosomal structural rearrangement type. What is known already Chromosomal structural rearrangements (SR) are associated with altered gametogenesis, resulting in the formation of gametes with chromosomal imbalances. For affected couples, undergoing IVF cycles with PGT-SR is recommended to select embryos with a normal or balanced karyotype. Scarce data exist on IVF laboratory outcomes in couples undergoing PGT-SR cycles. Findings regarding blastocyst rate, mainly focused on high-quality blastocysts, remain unclear. In addition, structural rearrangement carriers yield fewer transferable blastocysts than patients undergoing PGT-A. Conclusive evidence regarding the influence of carrier gender and type of chromosomal SR on the development of transferable blastocysts is lacking, with existing studies yielding contradictory results. Study design, size, duration This retrospective cohort study was conducted at a single university-affiliated obstetrics and fertility center between January 2019 and November 2023. The analysis involved 558 patients undergoing IVF cycles, including 136 in PGT-SR and 422 in PGT-A cycles. Participants/materials, setting, methods Trophectoderm biopsies from day 5/6/7 blastocysts underwent comprehensive chromosome screening utilizing validated NGS. Propensity Score Matching with a 1:1 match ratio was performed to balance baseline characteristics between the PGT-SR and PGT-A groups. The impact of chromosomal structural rearrangements on laboratory outcomes was assessed using a logistic regression model. Subsequently, within the PGT-SR population, the association between the carrier’s gender and the transferable blastocyst rate was evaluated through logistic regression, adjusting for potential confounders. Main results and the role of chance There was no significant difference in the fertilization rate between the PGT-A and PGT-SR groups (OR = 1.26, 95% CI 1.01-1.60, p-value=0.14). However, the PGT-SR group exhibited a significantly lower overall blastulation rate (36.7%) compared to the PGT-A group (42.8%) (OR = 0.76, 95% CI 0.63-0.93, p-value=0.03). Notably, a significant difference was observed in the top-quality blastocyst rate, with PGT-A patients showing a rate of 21.7% versus 9.57% in PGT-SR patients (OR = 0.45, 95% CI 0.29-0.69, p-value&amp;lt;0.01). In the PGT-SR cohort, female carriers constituted 44.1%, while male carriers were 56.6%. Reciprocal translocations represented 56.5% of the structural rearrangements, with the remaining 43.5% being other types. When comparing female to male carriers, no significant association was observed between the transferable blastocyst rate and the carrier’s gender (OR = 0.90, 95% CI = 0.35-2.31, p-value=0.83). However, a notable association was identified between the transferable blastocyst rate and the type of structural chromosomal rearrangements (OR = 0.16, 95% CI = 0.09-0.29, p-value&amp;lt;0.01). Specifically, in cases where the patient carried a chromosomal SR other than reciprocal translocation, the transferable blastocyst rate was 83.2%, in contrast to 44.9% in patients with reciprocal translocations. Limitations, reasons for caution The retrospective design of this study represents a limitation, and the limited sample size of patients with structural chromosomal rearrangements restricts the statistical power. Wider implications of the findings These findings reveal that patients with SR yield fewer embryos for biopsy than those undergoing PGT-A, showing a reduced rate of transferable blastocysts in cases of reciprocal translocations. Consequently, providing comprehensive counseling and managing expectations for couples undergoing PGT-SR is essential. Trial registration number not applicable

O-025 An artificial intelligence (AI) model non-invasively evaluates endometrial receptivity from ultrasound images, surpassing endometrial thickness (EMT) in predicting implantation

Abstract Study question Can an AI image-based model be trained to predict whether an endometrium, prior to progesterone, is receptive for successful embryo implantation from ultrasound images? Summary answer An endometrial receptivity AI model, utilizing ultrasound images and clinical features, is predictive of successful implantation and outperforms endometrial thickness as a predictor of implantation. What is known already Despite its importance in successful embryo implantation and subsequent live birth, endometrial receptivity is difficult to measure. The standard of care at some clinics is to cancel an embryo transfer if EMT is measuring less than 7 mm on ultrasound assessment – however, achieving an EMT threshold does not guarantee success, even with euploid blastocysts. Currently available receptivity tests (e.g. endometrial receptivity assays) are unreliable and have not shown significant improvements in reproductive outcomes, necessitating the development of new evaluation methods for endometrial receptivity. AI can potentially address this gap in clinical care and understanding, aiming to increase patient success. Study design, size, duration 79,602 ultrasound images (40,910 patients) of the endometrium, on the day of progesterone start according to patient’s frozen embryo transfer cycle, were retrospectively collected from 4 clinic networks including 70 clinic locations. PGT-A outcomes and blastocyst quality were available for 15,466 and 36,070 blastocysts respectively, with 14,538 having labels for both. Different image samples (based on embryo quality) were selected to train and test several AI models, with implantation (positive beta-hCG) as a binary outcome. Participants/materials, setting, methods Three criteria for negative (implantation) class sample selection were tested for receptivity model development: 1) high- or medium-quality and/or euploid blastocysts; 2) high-quality blastocysts; 3) all blastocysts. Models were ensembles consisting of an image-based deep learning (DL)-model and a feature-based machine learning (ML)-model. Model performance was measured by Area-under-the-curve (AUC), sensitivity, and specificity. Feature importance from the ML model was assessed, while receptivity model performance was compared to the power of EMT to predict implantation. Main results and the role of chance A receptivity model trained on scenario 1) (n = 27,424) achieved AUC 0.613, sensitivity 0.716, and specificity 0.439 on a test set of 9197 samples, in predicting implantation. Another receptivity model trained on scenario 2) (n = 25,625) achieved AUC 0.627, sensitivity 0.637, and specificity 0.543 on a test set of 8642. Whereas a third receptivity model trained on scenario 3) (n = 31,238) was selected for further analysis as it attained the best performance with AUC 0.631, sensitivity 0.628, and specificity 0.556 on a test set of 10,422. The ensemble model also utilizes relevant clinical features, which were ranked by importance to model predictions: EMT; progesterone blood test value; age at transfer; previous total embryo transfers; days between ultrasound date and transfer date; age at retrieval; and oocyte origin. EMT was assessed for its ability to predict implantation at thresholds between 5–20 mm. The threshold that best separates positive and negative implantation was determined by evaluating AUC on a validation set of 5682. A threshold of 8.8 mm achieved an AUC 0.576, sensitivity 0.694, and specificity 0.455 in predicting implantation on a test set of 5686. However, the receptivity model AUC (0.631) was significantly higher (p &amp;lt; 0.001; DeLong test for differences in AUC), outperforming EMT predictability. Limitations, reasons for caution The endometrial receptivity model was built and tested on retrospective frozen embryo transfer data. Results should be corroborated in prospective and non-selection studies, as well as in multiple geographical locations (all clinics included reside in the United States). The dataset requires greater diversification, with a greater representation of EMT (&amp;lt;7mm). Wider implications of the findings This study indicates that an AI model can be built to predict implantation from ultrasound images and clinical features, surpassing current standards - EMT alone. Further experimentation, with additional clinical features, may improve performance to facilitate development of a model that can accurately predict the gold-standard of live birth. Trial registration number Not applicable

P-132 Outcomes of blastocyst transfer derived from oocytes with smooth endoplasmic reticulum clusters (sERC)

Abstract Study question Are blastocysts derived from oocytes with smooth endoplasmic reticulum clusters (sERC+) as suitable for transfer as those from oocytes without such clusters (sERC-)? Summary answer Blastocysts from sERC+ oocytes are considered for embryo transfer; however, it is recommended to prioritize them lower than those from sERC- oocytes. What is known already One of the cytoplasmic abnormalities in human oocytes, sERC, typically manifests during the MII stage oocytes and disappears after fertilization when the female and male pronuclei emerge. Despite this, the mechanism behind sERC development remains unclear. While it is suggested that sERC in oocytes may adversely impact embryo development and implantation, a definitive conclusion on its safety or use has not been reached. Although the 2011 Istanbul consensus discouraged injecting or inseminating sERC+ oocytes, a 2017 expert panel reconsidered this recommendation, advocating for a case-by-case approach. Therefore, there are widespread variations in responses to sERC in clinical practices. Study design, size, duration A retrospective review of intracytoplasmic sperm injection (ICSI) cycles between April 2014 and April 2023 was conducted, exclusively on single frozen blastocyst transfers of two pronuclei (2PN)-derived embryos performed before June 2023. A dataset comprising 95 blastocysts from sERC+ oocytes and 8,698 blastocysts from sERC- oocytes was assembled. To reduce bias between groups, maternal age at retrieval and transfer counts were matched in a 1:1 ratio using propensity score matching, yielding 95 comparable cycle pairs. Participants/materials, setting, methods Among all ICSI cycles, 78 exclusively involved embryos from sERC+ oocytes, 847 included embryos from both sERC+ and sERC- oocytes, and 6,599 had no embryos derived from sERC+ oocytes. Among the 8,698 sERC- blastocysts transferred, 1,083 and 7,615 originated from cycles with and without sERC+ oocytes, respectively. Implantation, miscarriage, and live birth rates were then compared in 95 matched pairs of blastocysts derived from sERC+ and sERC- oocytes. Main results and the role of chance Following propensity score matching adjustments, the mean patient age at retrieval (mean ± SD) for blastocyst transfers derived from sERC+ and sERC- oocytes were 38.6 ± 4.7 years and 38.7 ± 4.8 years, respectively (p = 0.927). The transfer counts were 4.2 ± 3.4 times for sERC+ and 4.1 ± 3.1 times for sERC- blastocyst transfers (p = 0.840). The proportion of high-quality blastocysts was 48.4% for sERC+ transfers and 54.7% in sERC- transfers (p = 0.384). The implantation rates were 24.2% for sERC+ and 32.6% for sERC- transfers (p = 0.198), miscarriage rates were 43.5% vs. 35.5% (p = 0.552), and live birth rates were 13.7% vs. 21.1% (p = 0.172), respectively, with no statistically significant differences. Thirteen live births from sERC+ blastocyst transfers were recorded, and no congenital abnormalities were observed. Limitations, reasons for caution This study exclusively centered on oocytes subjected to ICSI, and the inclusion criteria were restricted to embryos derived from sERC+ oocytes in accordance with clinic policy limitations. Preimplantation genetic testing was not performed on the majority of the transferred embryos. Wider implications of the findings No congenital abnormalities were observed in live births resulting from sERC+ derived blastocyst transfers. However, the limited number of embryo transfers involving sERC+ oocytes poses a constraint in drawing a definitive conclusion regarding the safety of embryos from sERC+ oocytes, and further data is required. Trial registration number non-clinical trials

P-128 Non-invasive morphometric assessment of embryo quality: Effectiveness of the number of trophectoderm cells at the equatorial region of expanded blastocysts

Abstract Study question Does the number of trophectoderm cells at the equatorial region of expanded blastocysts (eTEs) affects pregnancy rate in single vitrified blastocyst transfer (SVBT)? Summary answer The number of eTEs highly correlated with the total number of TEs. The greater number of eTEs was higher pregnancy rate became. What is known already The increased use of blastocyst transfer has emphasized the importance of selecting high-quality embryos. Morphological grading: Gardner’s criteria, or time-lapse imaging of embryo morpho kinetics is established a tool for selection of high-quality blastocysts. The Gardner’s criteria is one of the most used evaluation according to grading scores of developmental stage, trophectoderm (TE) and inner cell mass (ICM). Although, it cannot completely exclude subjectivity, and it varies from observer to observer. A quantitative evaluation method for blastocyst selection is necessary to solve these problems and to improve the pregnancy rate of SVBT. Study design, size, duration First, we checked the correlation between the number of eTEs and the total number of TEs using 23 discarded blastocysts by immunostaining of CDX2. Then, we analyzed 1103 vitrified-warmed blastocysts from July 2017 to June 2021 for pregnancy rates. Expanded blastocysts which reached the blastocoel cavity of 160 µm or more with obvious ICM were vitrified and cryopreserved. Relationship between the number of eTEs and pregnancy rate after SVBT was analyzed by logistic regression. Participants/materials, setting, methods CDX2-positive cells were defined as TE, and the difference between total cells by Hoechst staining and CDX2-positive cells as ICM. The correlation between the number of eTEs and the total number of TEs was examined. In SVBT, all embryos were monitored by a time-lapse system. eTEs were counted in the time-lapse image just before cryopreservation. Pregnancy and abortion rates were examined for each eTEs. Also, logistic regression analysis was performed on eTEs and pregnancy. Main results and the role of chance There was a strong positive correlation between the number of eTEs and the total number of TEs (CDX2-positive cells) in the whole blastocysts (r = 0.945). In addition, there was a significant correlation between the number of eTEs and the total cell number of blastocysts (r = 0.73). On the other hand, there was no correlation between the number of eTEs and the cell number of ICM (r = 0.008). The number of eTEs was presented as quartiles: Pregnancy rates for &amp;lt;5, 5-6, 6-7 and ≥7 eTEs were 25.9, 29.4, 38.4, and 64.2% (P &amp;lt; 0.05), respectively, and the miscarriage rates were 50.0, 28.3, 14.1 and 19.2% (P &amp;lt; 0.05), respectively. Pregnancy rate for ≥7 eTEs was significantly higher than that for the other groups (P &amp;lt; 0.05), and miscarriage rate was lower than that for &amp;lt;6 eTEs. That is, increased eTEs significantly increased the pregnancy rate and decreased the miscarriage rate. Significant relationship between the number of eTEs and pregnancy was shown by logistic regression analysis (P &amp;lt; 0.0001), with an AUC of 0.68 and a cutoff value of 6.5. Limitations, reasons for caution In this study, expanded blastocysts at 160 µm or more in diameter were analyzed and cryopreserved. The different size of blastocysts may be different number of eTEs, and the relationship between the number of eTEs and pregnancy rate will be needed to confirm in individual clinic. Wider implications of the findings Quantitative analysis of eTEs makes it possible to select highly fertile blastocysts. This assessment is simply and easy. It can be the additional possible evaluation before cryopreservation to allows for quantitative treatment of continuous variables by classifying them in more detail than Gardner’s criteria. Trial registration number N/A

P-167 The sperm parameters in doubling oocytes by the 1st polar body transfer technique: does it matter?

Abstract Study question Does sperm parameters affect the effectiveness of the 1st polar body (PB) transfer in oocytes and embryo doubling? Summary answer Certain sperm conditions affect the transfer technique efficiency. What is known already Previous studies have shown the effectiveness of the 1st polar body (PB) transfer. The technique allows for the modification of donor oocytes to increase the number of cells suitable for fertilization and at the same time preserve the genetic relatedness to the patient. We established that the effectiveness depends on the morphology of the 1stPB. We also showed that the yield of high-quality blastocysts does not depend on whether fresh or thawed donor oocytes are used. But it is also important to understand whether sperm parameters have a significant effect on the performance of the technique. Study design, size, duration The study was performed in the Medical Center IGR from December 2017 to December 2023 and involved 93 patients (mean age 39.7±5.4 years) who underwent the 1st PB transfer and had indicated sperm parameters used for fertilization, including: normozoospermia (NS, n = 43), asthenozoospermia (AS, n = 24), asthenoteratozoospermia (ATS, n = 20), oligozoospermia (OS, n = 5), cryptozoospermia (CS, n = 1). We evaluated the pronuclear scoring, number of embryos on the 3rd and the 5th post-fertilization day, euploidy according to sperm conditions. Participants/materials, setting, methods We used donor oocytes, patients’ oocytes and their 1stPBs obtained from 93 women and their partners sperm with defined parameters in accordance with WHO norms for 2021. The procedure of donor oocyte enucleation and the 1stPBs transfers was carried out using Nikon Ti Eclipse(Japan) inverted microscope, Saturn 3 laser console(UK). Preimplantation genetic testing for aneuploidy was performed using trophectoderm biopsy. Samples were diagnosed using Ion S5(USA). Statistical analysis was carried out using Chi-square test. Main results and the role of chance The total number of donor oocytes modified by the 1stPB of patient’ oocytes was 364, which were distributed as follows by sperm status: NS - 159 oocytes, AS - 103 oocytes, ATS - 77 oocytes, OS - 19 oocytes, and CS - 6 oocytes. The mean age of the female patients according to the groups was similar (39.6±4.9, 39.8±6.2, 40.0±3.8, 37.8±6.1,40, respectively). The number of 2PN pattern during pronuclear scoring was distributed among groups (NS:AS:ATS:OS:CS) with the following percentages 69.2:65.1:62.3:73.7:66.7, respectively. Among the developing embryos on the 3rdday the distribution was 46.6:46.5:36.4:57.9, respectively. No viable embryos were formed in the CS group, so the group was not included in further calculations. Statistically significant difference (SSD) was not found between the groups on the above-mentioned stages of development (p0.05). On the 5thday the number of developing embryos (percents) was distributed as follows: 23.3:28.2:11.7:31.6 for NS:AS:ATS:OS, respectively. It is worth noting that SSD was found between NS and ATS, OS and ATS groups (p &amp;lt; 0.05) and AS and ATS groups (p &amp;lt; 0.001). Percentage of euploid embryos relative to the number of examined blastocysts from groups NS:AS:ATS was 30.8:23.1:22.2, respectively, SSD wasn’t found between the groups(p &amp;gt; 0.05). Limitations, reasons for caution To increase performance of the 1st PB transfer technique it is also worth considering such parameters as sperm DNA fragmentation and level of sperm oxidative stress, which reflect the chromatin state of the male gamete. Wider implications of the findings The study showed that among patients with asthenoteratozoospermia, the yield of viable embryos was significantly lower compared to the other sperm conditions studied. This fact must be taken into account when predicting the result of using the 1st PB transfer technique. Trial registration number N/A

P-213 Effectiveness and safety of single poor quality blastocyst transfer compared with single good quality blastocyst transfer in the first transfer cycle

Abstract Study question Comparison of pregnancy and perinatal outcomes in blastocysts with poor inner cell mass quality or poor trophectoderm quality to optimize non-quality single blastocyst transfer strategies. Summary answer Poor trophoblast quality blastocysts have better pregnancy outcomes than poor inner cell mass quality blastocysts, with no statistically significant difference in perinatal outcomes What is known already There is no doubt that good-quality blastocysts have better pregnancy outcomes than poor-quality blastocysts, but the preference for trophectodermal poor-quality blastocysts or inner cell mass poor-quality blastocysts in non-good-quality blastocyst cycles is still uncertain. Study design, size, duration A total of 46,433 first single blastocyst transfer cycles from March 1, 2014, to December 31, 2022 were retrospectively analyzed, and blastocyst transfer cycles were divided into 3 groups according to the grade of trophoderm and inner cell mass: A/B A/B (Group 0, N = 30748), A/B C (Group 1, N = 15455), and C A/B (Group 2, N = 230). Participants/materials, setting, methods 46,433 patients who underwent their first single blastocyst transfer at Reproductive and Genetic Hospital of CITIC-Xiangya were included. Multivariate log-binomial regression model with COPY methods were performed to estimate relative risk of Group 2/1 versus Group 0 and Group 2 versus Group 1 for reproductive and neonatal outcomes. Five propensity score weighting methods, namely IPW, processing, overlap, matching, and entropy, were used for sensitivity analysis to explore the robustness of the results. Main results and the role of chance After adjusting for female age, BMI, duration of infertility, number of cycles, AFC, AMH, endometrial thickness, causes of infertility (tubal disorders, ovulatory disorders, endometriosis, unexplained, more than one causes, male factors), culture days (D5, D6), expansion of blastocyst (3, 4, 5, 6), and type of blastocyst (fresh blastocyst, thawed blastocyst, thawed cleavage cultured to blastocyst, PGT blastocyst), we found that clinical pregnancy rate (CPR) and live birth rate (LBR) of Group 0, Group 1 and Group 2 were successively significantly decreased (CPR: Group 1 vs Group 0, RR = 0.83 (0.81, 0.84), Group 2 vs Group 0, RR = 0.43 (0.35, 0.53), Group 2 vs Group 1, RR = 0.53 (0.42, 0.64); LBR: Group 1 vs Group 0, RR = 0.79 (0.77, 0.81), Group 2 vs Group 0, RR = 0.36 (0.27, 0.47), Group 2 vs Group 1, RR = 0.45 (0.34, 0.59); respectively), while early miscarriage rate was successively significantly increased (Group 1 vs Group 0, RR = 1.3 (1.22, 1.38), Group 2 vs Group 0, RR = 2.25 (1.46, 3.15), Group 2 vs Group 1, RR = 1.73 (1.12, 2.42)). Late miscarriage, preterm birth, singleton live birth, sex ratio of singleton, low birth-weight of singleton, and birth weight of singleton were not statistically different between three groups. Above results were robust in our two sensitivity analysis. Limitations, reasons for caution As a retrospective study, there are inevitably unmeasured confounding factors. This study only included a small number of Group 2. It’s therefore possible that our study was under powered. Risk of gestational hypertension, gestational diabetes, cesarean section and macrosomia should also be evaluated with a more comprehensive assessment of safety. Wider implications of the findings High-quality blastocysts have better pregnancy and live birth rates than poor-quality blastocysts, but there are no significant differences in preterm birth, sex ratio, or birth weight. In the absence of good quality blastocysts for transplantation, poor quality blastocysts of the trophectoderm are preferred over poor quality inner cell mass. Trial registration number not applicable

Oil-soluble contrast medium bathing attenuated endometrial inflammation and improved endometrial receptivity in women with recurrent implantation failure: a descriptive study

BackgroundThe oil-soluble contrast medium used in hysterosalpingography has been shown to have a fertility-enhancing effect, but the underlying mechanism is unclear, especially regarding the role of window of implantation (WOI). This study aimed to assess the endometrial immunological impact of the WOI before and after bathing with the oil-soluble contrast medium in women with recurrent implantation failure (RIF).MethodsThis descriptive study involved two medical centers between December 18, 2019, and December 30, 2020. We included infertile women who underwent three or more transfer cycles, cumulative transplantation of at least four high-quality cleavage-stage embryos or three high-quality blastocysts without clinical pregnancy, and high-quality frozen embryos that were still available for implantation. Patients received 5 ml of ethiodized poppyseed oil bathing, endometrial biopsy around bathing, and frozen-thawed embryo transfer (FET) within four menstrual cycles after bathing. Patients were excluded if failure to complete anyone. Data on the baseline characteristics and clinical data of the FET cycles were collected, and endometrial biopsy specimens were collected in the luteal phase before and after bathing and subjected to immunohistochemistry. The number of CD56 and CD138 positive cells and H-score of expression of ανβ-3 and HOXA10 in endometrium were collected.ResultsThirty-four patients were initially enrolled in the study; ultimately, twelve patients with a median age of 32.5 years (range 27–40 years) completed the research. The median number of embryo transfer cycles was three (range 3–8). A total of 4 of 12 women (33.33%) were diagnosed with chronic endometritis before oil-soluble contrast bathing. After bathing, the median numbers of CD138-positive cells in endometrium decreased from 0.75 (range 0–13.5) to 0.65 (range 0–6), P = 0.035; additionally, the H-score of expression of ανβ-3 in endometrium increased from 148.50 ± 31.63 to 175.58 ± 31.83, P < 0.001. The thickness of the endometrium also significantly increased (8.90 ± 1.45 mm vs.10.11 ± 1.98 mm, P = 0.005). However, no consistent changes were found in the expression of CD56 and HOXA10 in the endometrium. Five patients experienced biochemical pregnancies (41.67%), four had clinical pregnancies (33.33%), and three achieved live births following oil-soluble contrast bathing (25%).ConclusionsThese results suggest that oil-soluble contrast medium bathing decreased CD138-positive cells and upregulated expression of ανβ-3 during WOI in patients with RIF. This histological impact of endometrium may result in enhanced fertility during FET cycles. Investigating the ability of intrauterine bathing with lower-dosage oil-soluble contrast to improve pregnancy in the RIF population is warranted.