Single Blastocyst Transfer Research Articles

Effect of progesterone concentration on hCG trigger day on clinical outcomes after high-quality single blastocyst transfer in GnRH antagonist cycles.

To investigate whether progesterone levels on the human chorionic gonadotropin (hCG) trigger day are associated with clinical outcomes in fresh cycles and the first frozen-thawed cycles (the freeze-all strategy) following the transfer of a high-quality single blastocyst. This single-center retrospective analysis was conducted on patients undergoing in vitro fertilization with the gonadotropin-releasing hormone (GnRH) antagonist protocol from January 2017 to December 2023. The study included the first and second oocyte retrieval cycles with progesterone levels ≤2 ng/ml on hCG trigger day. Clinical pregnancy rates and early miscarriage rates were compared among groups using curve fitting, threshold effect analysis, and multivariable regression. When progesterone levels were between 1 and 2 ng/ml, the pregnancy rate in fresh cycles was only 51% of that in cycles with progesterone levels ≤1 ng/ml (95% CI: 0.33, 0.79, p = 0.0028). And the pregnancy rate decreased by 25% (95% CI: 0.51, 1.09) for frozen cycles, although there was no statistically significant (p = 0.1273). When cycle types were used as a binary variable in multivariate regression analysis, it was found that the clinical pregnancy rate in frozen cycles was 1.84 times higher than in fresh cycles (OR = 1.84, 95% CI: 1.38-2.47). For progesterone levels between 1 and 2 ng/ml, the clinical pregnancy rate in frozen cycles was 2.90 times that of fresh cycles (OR = 2.90, 95% CI: 1.59, 5.29, p = 0.0015). Progesterone levels on hCG day had no impact on the clinical pregnancy rate in thaw cycles, nor did they affect miscarriage rates in fresh or thaw cycles (p > 0.05). When progesterone levels on hCG trigger day were between 1 and 2 ng/ml, the clinical pregnancy rate for frozen-thawed cycles of high-quality single blastocyst transfer using an GnRH antagonist protocol significantly surpasses that of fresh cycles, thus elective frozen embryo transfer after the freeze-all strategy is recommended.

Identifying key predictive features for live birth rate in advanced maternal age patients undergoing single vitrified-warmed blastocyst transfer

BackgroundInfertility affects one in six couples worldwide, with advanced maternal age (AMA) posing unique challenges due to diminished ovarian reserve and reduced oocyte quality. Single vitrified-warmed blastocyst transfer (SVBT) has shown promise in assisted reproductive technology (ART), but success rates in AMA patients remain suboptimal. This study aimed to identify and refine predictive factors for live birth following SVBT in AMA patients, with the goal of enhancing clinical decision-making and enabling personalized treatment strategies.MethodsThis retrospective cohort study analyzed 1,168 SVBT cycles conducted between June 2016 and December 2022 at the First Affiliated Hospital of Guangxi Medical University and Nanning Maternity and Child Health Hospital. Nineteen machine-learning models were applied to identify key predictive factors for live birth. Feature selection and 10-fold cross-validation were employed to validate the models.ResultsThe most significant predictors of live birth included inner cell mass quality, trophectoderm quality, number of oocytes retrieved, endometrial thickness, and the presence of 8-cell blastomeres on day 3. The stacking model demonstrated the best predictive performance (AUC: 0.791), followed by Extra Trees (AUC: 0.784) and Random Forest (AUC: 0.768). These models outperformed traditional methods, achieving superior accuracy, sensitivity, and specificity.ConclusionLeveraging advanced machine-learning models and identifying critical predictive factors can improve the accuracy of live birth outcome predictions for AMA patients undergoing SVBT. These findings offer valuable insights for enhancing clinical decision-making and managing patient expectations. Further research is needed to validate these results in larger, multi-center cohorts and to explore additional factors, including fresh embryo transfers, to broaden the applicability of these models in clinical practice.

The TLI system can help day-3 single cleavage embryo transfer to obtain comparative clinical outcomes to day-4 or day-5.

The aim was to explore whether the time-lapse imaging system can help day-3 single cleavage embryo transfer to obtain comparative clinical outcomes to day-4 or 5. The data of 1237 patients who underwent single embryo transfer from January 1, 2018, to September 30, 2020, in our reproductive medicine centre were retrospectively analysed. They were divided into the day-3 single cleavage-stage embryo transfer (SCT) group (n = 357), day-4 single morula transfer (SMT) group (n = 129) and day-5 single blastocyst transfer (SBT) group (n = 751) according to the different embryo transfer stage. The clinical and perinatal outcomes of the three groups were analysed and compared. The clinical pregnancy rates of the patients in the day-3 SCT group, day-4 SMT group and day-5 SBT group were 68.07, 70.54 and 72.04%, respectively. The live birth rates were 56.86, 61.24 and 60.99%, respectively. The monozygotic twin (MZT) rate in the day-3 SCT group was significantly lower than that in the day-5 SBT group (P = 0.049). Regarding perinatal outcomes, only the secondary sex ratio had a significant difference (P < 0.05). After age stratification, no improvement was found in the pregnancy outcomes of patients >35 years of age receiving blastocyst transfer. Our findings suggest that for patients with multiple high-quality embryos on day-3, prolonging the culture time can improve the pregnancy outcome to some extent, but it will bring risks. For centres that have established morphodynamic models, day-3 SCT can also achieve an ideal pregnancy outcome and reduce the rate of monozygotic twins and sex ratio.

Effect of single blastocyst-stage versus single cleavage-stage embryo transfer on cumulative live births in women with good prognosis undergoing in vitro fertilization: Multicenter Randomized Controlled Trial

In this multicenter, non-inferiority, randomized trial, we randomly assigned 992 women undergoing in-vitro fertilization (IVF) with a good prognosis (aged 20-40, ≥3 transferrable cleavage-stage embryos) to strategies of blastocyst-stage (n = 497) or cleavage-stage (n = 495) single embryo transfer. Primary outcome was cumulative live-birth rate after up to three transfers. Secondary outcomes were cumulative live-births after all embryo transfers within 1 year of randomization, pregnancy outcomes, obstetric-perinatal complications, and livebirths outcomes. Live-birth rates were 74.8% in blastocyst-stage group versus 66.3% in cleavage-stage group (relative risk 1.13, 95%CI:1.04-1.22; Pnon-inferiority < 0.001, Psuperiority = 0.003) (1-year cumulative live birth rates of 75.7% versus 68.9%). Blastocyst transfer increased the risk of spontaneous preterm birth (4.6% vs 2.0%; P = 0.02) and neonatal hospitalization >3 days. Among good prognosis women, a strategy of single blastocyst transfer increases cumulative live-birth rates over single cleavage-stage transfer. Blastocyst transfer resulted in higher preterm birth rates. This information should be used to counsel patients on their choice between cleavage-stage and blastocyst-stage transfer (NCT03152643, https://clinicaltrials.gov/study/NCT03152643).

Success Rates with Preimplantation Genetic Testing for Aneuploidy (PGT-A) in Good Prognosis Patients is Dependent on Age.

To evaluate cumulative live birth following preimplantation genetic testing for aneuploidy (PGT-A) with next generation sequencing (NGS) compared to morphology alone among patients aged 21-40 years undergoing single blastocyst transfer. Retrospective cohort study SUBJECTS: Patients aged 21 to 40 years undergoing first, autologous retrieval cycles resulting in ≥ 5 fertilized oocytes, with subsequent single blastocyst transfer in SART clinics from 2016 to 2019. PGT-A using NGS MAIN OUTCOME MEASURES: The primary outcome was cumulative live birth per retrieval. Secondary outcomes included clinical pregnancy, miscarriage, and live birth per transfer. A total of 56,469 retrieval cycles were included in the analysis. Retrieval cycles were stratified based on age (< 35, 35-37, and 38-40 years) and exposure to PGT-A with NGS. Modified Poisson regression modeling was used to evaluate the association between PGT-A and cumulative live birth per retrieval while controlling for covariates. In this cohort, most cycles did not utilize PGT-A (n=49,608; 88%). After adjusting for covariates, the use of PGT-A was associated with a slightly lower cumulative live birth in individuals aged <35 years (risk ratio [RR] 0.96; 95% CI: 0.93, 0.99) compared with no PGT, but higher cumulative live birth in ages 35-37 years (RR 1.04; 95% CI: 1.00, 1.08), and 38-40 years (RR 1.14; 95% CI: 1.07, 1.20). A subgroup analysis limited to freeze-all cycles (n=29,041) showed that PGT-A was associated with higher cumulative live birth in individuals aged ≥ 35 years and was similar to no PGT in individuals aged < 35 years. Miscarriage was significantly less likely in individuals aged ≥ 35 years utilizing PGT-A compared with no PGT-A. In this large national database study, success rates in cycles utilizing PGT-A were dependent on age. Cumulative live birth was observed to be significantly less likely in PGT-A cycles among individuals aged < 35 years and more likely among individuals aged 38 to 40 years, compared to no PGT-A. In individuals with no fresh transfer, results were similar. Moreover, miscarriage was significantly less likely with PGT-A among individuals aged 35-40 years in a subgroup analysis of freeze-all cycles.

Assessing the effect of below-benchmark vitrified/warmed donor-oocyte survival rates in subsequent laboratory and clinical outcomes

To assess the impact of below-benchmark (95-100%) donor oocyte survival rates to vitrification/warming in the laboratory and clinical outcomes of recipient cycles. Retrospective cohort study. We analyzed 12690 vitrified-warmed donor oocyte recipient cycles carried out in a network of European private IVF units from 2018-2022. All cycles analyzed used exclusively vitrified/warmed donor oocytes. The cycles were grouped according to the survival rate experienced: benchmark 95-100%; competence 85-95%; below-competence 70-85%; poor 50-70%; very poor <50%. The primary endpoint of the study was the total usable blastocyst rate per 2PN zygote. Secondary endpoints were the fertilization rate, the live birth rate after the first single blastocyst transfer, and the cumulative live birth rate. The mean number of warmed oocytes per ICSI cycle was 11.4±3.2 with a mean survival rate of 89.1%. More oocytes per cycle were consumed in the lower survival groups, yet the total oocytes available for ICSI was smaller in the below-competence, poor and very-poor survival groups. The total usable blastocyst rate was lower in the lower survival groups (benchmark: 48.9%; competence: 47.0%, below-competence: 46.0%; poor: 43.6%; very-poor:43.6%, p<0.001), as well as the fertilization rates (benchmark: 76.8%; competence: 76.6%, below-competence: 75.6%; poor: 74.7%; very-poor:75.5%, p<0.001). The adjusted relative risk of live-birth rate of the first embryo transferred was equal to the benchmark survival group in all the lower survival groups (Benchmark: 40.9%; Competence: RR=0.986, 95%CI:0.931-1.045; below-competence: RR=0.992, 95%CI:0.929-1.059; poor: RR=1.103, 95%CI:1.009-1.207; and very-poor: RR=1.169, 95%CI:0.963-1.419). The cumulative live-birth rate decreased in lower survival groups compared to benchmark survival (Benchmark: 79.2%; Competence: RR=0.988, 95%CI:0.961-1.015; below-competence: RR=0.911, 95%CI:0.880-0.944; poor: RR=0.802, 95%CI: 0.757-0.851; and very-poor: RR=0.793, 95%CI: 0.693-0.907). The lower cumulative rates maintained in a sub-analysis with equal M-II available for ICSI (Benchmark: 69.5%; Competence: RR=0.909, 95%CI:0.827-1.000; below-competence: RR=0.942, 95%CI:0.848-1.046; poor: RR=0.833, 95%CI:0.7386-0.941; and very-poor: RR=0.873, 95%CI:0.695-1.097). Lower donor-oocyte cryo-survival rates have a moderate negative impact on the blastocyst utilization rate per 2PN zygote, fertilization rate and the cumulative live-birth rates of a donation cycle, even after adjusting for equal M-II oocytes available for ICSI. Nonetheless, the surviving oocytes of a cohort seem to maintain a high competence level, with very similar laboratory outcomes, irrespectively of the cohort's survival rates, as well as equal implantation potential of the resulting blastocysts.

The efficacy of diazepam administration during embryo transfer: a retrospective multicenter cohort study on reproductive outcomes.

This retrospective multicenter cohort study aimed to investigate the impact of diazepam administration during embryo transfer on reproductive outcomes, focusing primarily on the live birth rate. Secondary outcomes included the positive beta-hCG rate, clinical pregnancy rate, miscarriage rate, ectopic pregnancy rate, and preterm birth rate. Data from 5607 embryo transfers, encompassing 465 cases with diazepam administration, were retrospectively analyzed. The study included single blastocyst transfers from 12 clinics in Portugal and Spain between January 2015 and December 2022. Comparison of reproductive outcomes between patients receiving diazepam and those who did not showed no statistically significant differences. Positive beta-hCG rates (60.8% non-diazepam vs. 60.4% diazepam, p = 0.92, adjusted p = 0.32) and clinical pregnancy rates (45.6% non-diazepam vs. 46.2% diazepam, p = 0.81, adjusted p = 0.11) were comparable. Miscarriage rates (11.0% diazepam vs. 9.3% non-diazepam, p = 0.25, adjusted p = 0.26) and ectopic pregnancy rates (0.9% diazepam vs. 0.1% non-diazepam, p = 0.1, adjusted p = 0.20) were similar. Live birth rates (36.3% non-diazepam vs. 35.3% diazepam, p = 0.69, adjusted p = 0.82) and prematurity rates (0.3% non-diazepam vs. 0% diazepam, p > 0.99, adjusted p = 0.99) also exhibited no statistically significant differences. Based on the results, diazepam administration during embryo transfer did not show a discernible impact on reproductive outcomes, including live birth rates, suggesting its limited effectiveness in enhancing success.

Trophectoderm grade is associated with the risk of placenta previa in frozen-thawed single-blastocyst transfer cycles.

Do obstetric and perinatal complications vary according to different blastocyst developmental parameters after frozen-thawed single-blastocyst transfer (SBT) cycles? Pregnancies following the transfer of a blastocyst with a grade C trophectoderm (TE) were associated with an increased risk of placenta previa compared to those with a blastocyst of grade A TE. Existing studies investigating the effect of blastocyst morphology grades on birth outcomes have mostly focused on fetal growth and have produced conflicting results, while the risk of obstetric complications has rarely been reported. Additionally, growing evidence has suggested that the appearance of TE cells could serve as the most important parameter for predicting implantation and live birth. Given that the TE ultimately develops into the placenta, it is plausible that this independent predictor may also impact placentation. This retrospective cohort study at a tertiary-care academic medical center included 6018 singleton deliveries after frozen-thawed SBT cycles between January 2017 and December 2021. Singleton pregnancies were grouped into two groups according to blastocyst developmental stage (Days 5 and 6), four groups according to embryo expansion (Stages 3, 4, 5, and 6), three groups according to inner cell mass (ICM) quality (A, B, and C), and three groups according to TE quality (A, B, and C). The main outcomes included pregnancy-induced hypertension, preeclampsia, gestational diabetes mellitus, preterm premature rupture of membrane, placenta previa, placental abruption, placenta accreta, postpartum hemorrhage, preterm birth, low birth weight, small for gestational age, and birth defects. Multivariate logistic regressions were performed to evaluate the effect of blastocyst developmental stage, embryo expansion stage, ICM grade, and TE grade on measured outcomes adjusting for potential confounders. No association was found between blastocyst developmental stage and obstetric or perinatal outcomes both before and after adjusting for potential confounders, and similar results were found with regard to embryo expansion stage and ICM grade. Meanwhile, the incidence of placenta previa derived from a blastocyst with TE of grade C was higher compared with those derived from a blastocyst with TE of grade A (1.7%, 2.4%, and 4.0% for A, B, and C, respectively, P = 0.001 for all comparisons). After adjusting for potential covariates, TE grade C blastocysts had 2.81 times the likelihood of resulting in placenta previa compared to TE grade A blastocysts (adjusted odds ratio 2.81, 95% CI 1.11-7.09). No statistically significant differences were detected between any other measured outcomes and TE grades both before or after adjustment. The study is limited by its retrospective, single-center design. Additionally, although the sample size was relatively large for the study group, the sample size for certain subgroups was relatively small and lacked adequate power, particularly the ICM grade C group. Therefore, these results should be interpreted with caution. The study extends our knowledge of the potential downstream effect of TE grade on placental abnormalities. This study was supported by the National Key Research and Development Program of China (2023YFC2705500, 2023YFC2705501, 2023YFC2705505, 2019YFA0802604); National Natural Science Foundation of China (82130046, 82320108009, 82371660, 32300710); Shanghai leading talent program, Innovative research team of high-level local universities in Shanghai (SHSMU-ZLCX20210201, SHSMU-ZLCX20210200, SHSMU-ZLCX20180401), Shanghai Jiaotong University School of Medicine Affiliated Renji Hospital Clinical Research Innovation Cultivation Fund Program (RJPY-DZX-003), Science and Technology Commission of Shanghai Municipality (23Y11901400), Shanghai's Top Priority Research Center Construction Project (2023ZZ02002), and Three-Year Action Plan for Strengthening the Construction of the Public Health System in Shanghai (GWVI-11.1-36). The authors have no conflicts of interest to declare. N/A.

Efficacy of non-invasive chromosome screening, preimplantation genetic testing for aneuploidy, and morphological grading in selecting embryos of patients with advanced maternal age: a three-armed prospective cohort study

BackgroundNon-invasive chromosome screening (NICS) and trophectoderm biopsy preimplantation genetic testing for aneuploidy (TE-PGT) were both applied for embryo ploidy detection, However, the cumulative live birth rates (CLBR) of NICS and TE-PGT in older age groups have yet to be reported. This study aimed to ascertain whether NICS and TE-PGT could enhance the cumulative live birth rates among patients of advanced maternal age.MethodsA total of 384 couples aged 35–40 years were recruited. The patients were assigned to three groups: NICS, TE-PGT, and intracytoplasmic sperm injection (ICSI). All patients received frozen single blastocyst transfer. Patients in the NICS and TE-PGT groups underwent aneuploidy screening.ResultsWhen compared to the ICSI group, the CLBR was significantly higher in the NICS and TE-PGT groups (27.9% vs. 44.9% vs. 51.0%, p = 0.003 for NICS vs. ICSI, p < 0.001 for TE-PGT vs. ICSI). There were no significant differences in the clinical outcomes between the NICS and TE-PGT groups. Adjusting for confounding factors, the NICS and TE-PGT groups still showed a higher CLBR than the ICSI group (adjusted odds ratio (OR) 3.847, 95% confidence interval (CI) 1.939 to 7.634; adjusted OR 3.795, 95% CI 1.981 to 7.270). Additionally, the cumulative pregnancy loss rates of the NICS and TE-PGT groups were significantly lower than that of the ICSI group (adjusted OR 0.277, 95% CI 0.087 to 0.885; adjusted OR 0.182, 95% CI 0.048 to 0.693). There was no significant difference in the birth weights of the three groups (p = 0.108).ConclusionsIn women 35–40 years old, the CLBR can be increased by selecting euploid embryos using NICS and TE-PGT. For elderly women at high risk of embryonic aneuploidy, NICS, characterized by its safety and non-invasive nature, may emerge as an alternative option for preimplantation genetic testing.

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.

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.

Morphological quality on Day 3 affects the pregnancy outcomes of low-quality euploid blastocysts: a retrospective cohort study.

Does the morphological quality on Day 3 influence the pregnancy outcomes of euploid blastocysts? The morphological quality on Day 3 affects the clinical pregnancy rate (CPR) and live birth rate (LBR) of low-quality euploid blastocysts. The morphological grading of Day 3 embryos affects the pregnancy outcome of cleavage-stage embryos and is an excellent indicator to predict embryo development potential. However, it is still unclear whether morphological quality on Day 3 is associated with pregnancy outcomes of the euploid blastocyst. This retrospective cohort study comprised 1275 patients who received single euploid blastocyst transfer between January 2016 and August 2021 at a tertiary teaching hospital. Patients were grouped into two groups according to the morphological grading on Day 3 of transferred blastocysts: high-quality (HQ, including Grades I and II) Day 3 embryos and low-quality (LQ, Grade III) Day 3 embryos. The primary outcomes were CPR and LBR. Interactions of development days (Day 5 and Day 6) and morphological quality (high- and low-quality) of blastocysts with morphological quality of Day 3 embryos on pregnancy outcomes were tested in the stratified analysis and logistic regression models. The multivariate logistic regression analysis was conducted to investigate the independent effect of the morphological quality of Day 3 embryos on pregnancy outcomes after adjusting for potentially confounding factors. The CPR and LBR of the HQ Day 3 embryos group were statistically higher than those of the LQ Day 3 embryos group (CPR: 59.73% versus 49.70%, respectively, P = 0.015; LBR: 49.73% versus 41.21%, respectively, P = 0.041). The development days of blastocysts did not exhibit a multiplicative interaction with the morphological quality of Day 3 embryos on the CPR (P for interaction = 0.648) and LBR (P for interaction = 0.925). The morphological quality of blastocysts exhibits a multiplicative interaction with the morphological quality of Day 3 embryos on the CPR (P for interaction = 0.020) and LBR (P for interaction = 0.012). After adjusting for potential confounders, the HQ Day 3 embryo group was positively associated with the CPR (adjusted odds ratio (aOR): 2.10, 95% CI: 1.31-3.36, P = 0.002) and LBR (aOR: 1.97, 95% CI: 1.20-3.25, P = 0.008) of LQ blastocysts. However, the morphological quality on Day 3 was not significantly associated with the CPR (aOR: 0.95, 95% CI: 0.58-1.55, P = 0.835) and LBR (aOR: 0.86, 95% CI: 0.53-1.40, P = 0.550) of HQ blastocysts. Selection and confounding bias introduced by the retrospective design cannot be completely eliminated in this study, although multivariable logistic analysis was conducted to adjust for potential confounders. Also, some subgroups had small sample sizes, which may reduce statistical power. Moreover, participants in our study only received single euploid blastocyst transfer, and whether the results could apply to blastocysts with unknown ploidy status is unclear. This study found that the morphological quality on Day 3 was significantly associated with the CPR and LBR of LQ blastocysts; Therefore, when only LQ euploid blastocysts are available for transfer, blastocysts derived from HQ Day 3 embryos are recommended. No external funding was obtained. The authors have no conflicts of interest to declare. N/A.

Does Recurrent Implantation Failure Exist? Prevalence and Outcomes of Five Consecutive Euploid Blastocyst Transfers in 123 987 Patients

(Abstracted from Hum Reprod 2024;39(5):974–980 Recurrent implant failure (RIF) has been defined as repeated failed implantations following multiple embryo transfers. A landmark paper on RIF reported the cumulative sustained implantation and live birth rates achieved with 3 consecutive single euploid blastocyst transfers and found a similar live birth rate across the first 3 consecutive transfers with a “true” unexplained RIF rate of &lt;5% in the in vitro fertilization population.

Optimizing single blastocyst selection: the role of day 3 embryo morphology in vitrified-warmed blastocyst transfer cycles

Can day 3 embryo morphology serve as an independent criterion for optimal single blastocyst selection? This retrospective, single-centre cohort study included 1517 single vitrified-warmed blastocyst transfer (SVBT) cycles conducted between October 2019 and July 2022. The live birth rate (LBR) and other clinical outcomes of SVBT cycles were evaluated, considering both good-quality and non-good-quality day 3 embryos. The associations of day 3 morphological characteristics, encompassing number of blastomeres and embryo grade, were assessed. Multivariable analyses were undertaken using multiple models adjusted for day of blastocyst development and blastocyst grade. Blastocysts from good-quality day 3 embryos had significantly higher LBR compared with those from non-good-quality embryos for both day 5 (51.5% versus 42.9%; P = 0.013) and day 6 (25.1% versus 17.6%; P = 0.018) blastocysts. LBR did not differ significantly with number of blastomeres on day 3, regardless of day of blastocyst development (day 5/6) or blastocyst grade. LBR varied significantly by day 3 embryo grade for both day 5 (48.0%, 51.5%, 46.6% and 32.7% for grades I, II, III and IV-V; P = 0.005) and day 6 (41.5%, 23.6%, 15.9% and 16.1% for grades I, II, III and IV-V; P = 0.001) blastocysts. Multivariable logistic regression revealed that non-good-quality embryos and lower morphological grade (IV-V) on day 3 were significantly and negatively correlated with LBR, while the number of blastomeres on day 3 was not an independent factor. When selecting blastocysts of equal quality for SVBT cycles, those with higher day 3 morphological scores are preferred. Day 3 morphological evaluation is a valuable supplement to conventional selection methods.

Noneffectiveness of cryostorage duration on clinical and neonatal outcomes after single vitrified-warmed blastocyst transfers

BackgroundIn the current era of assisted reproductive technology, the strategy of single vitrified-warmed blastocyst transfer (SVBT) is acknowledged for positively impacting clinical outcomes and preventing the risk of multiple conceptions. Previous studies have indicated that blastocyst grade and the day of blastocyst positively correlate with outcomes. Moreover, storage duration has no significant effect on survival rates, clinical outcomes, and neonatal outcomes. However, some researchers express controversial opinions on cryostorage duration, and their findings suggest a negative impact on clinical outcomes. These results remain subject to controversy, and limited studies exist regarding the outcomes after SVBT. Therefore, our study aims to investigate the impact of the day of blastocyst, blastocyst grade, and blastocyst cryostorage duration on clinical and neonatal outcomes following SVBT in patients who underwent clomiphene-citrate-based minimal stimulation.Material and methodsIn this study, retrospective cohort study data collected from June 2015 to April 2023 included 2107 patients with first SVBT cycles who underwent a clomiphene-based minimal ovarian stimulation protocol or a drug-free natural protocol at the Ojinmed IVF Center. Patients were categorized into four groups based on blastocyst cryostorage duration: group 1 (< 2 months, n = 882), group 2 (3–6 months, n = 794), group 3 (7–12 months, n = 187), group 4 (13–24 months, n = 126), and group 5 (25–81 months, n = 118). The patient’s clinical and neonatal outcomes were compared with cryostorage duration after the propensity score matched.ResultMultivariable logistic regression analysis revealed that prolonged cryostorage duration insignificantly correlated with clinical outcomes. Additionally, neonatal outcomes are not correlated with cryostorage duration.ConclusionsThe patient must consider several parameters when selecting embryos for transfer, including the duration of cryostorage. Our study results show that for the first single vitrified-warmed blastocyst transfer of patients who underwent clomiphene citrate-based minimal stimulation, cryostorage duration does not affect outcomes.

Cellular mechanisms of monozygotic twinning: clues from assisted reproduction.

Monozygotic (MZ) twins are believed to arise from the fission of a single fertilized embryo at different stages. Monochorionic MZ twins, who share one chorion, originate from the splitting of the inner cell mass (ICM) within a single blastocyst. In the classic model for dichorionic MZ twins, the embryo splits before compaction, developing into two blastocysts. However, there are a growing number of ART cases where a single blastocyst transfer results in dichorionic MZ twins, indicating that embryo splitting may occur even after blastocyst formation. For monochorionic MZ twins, we conducted a comprehensive analysis of the cellular mechanisms involved in ICM splitting, drawing from both ART cases and animal experiments. In addition, we critically re-examine the classic early splitting model for dichorionic MZ twins. We explore cellular mechanisms leading to two separated blastocysts in ART, potentially causing dichorionic MZ twins. Relevant studies including research articles, reviews, and conference papers were searched in the PubMed database. Cases of MZ twins from IVF clinics were found by using combinations of terms including 'monozygotic twins' with 'IVF case report', 'ART', 'single embryo transfer', or 'dichorionic'. The papers retrieved were categorized based on the implicated mechanisms or as those with unexplained mechanisms. Animal experiments relating to MZ twins were found using 'mouse embryo monozygotic twins', 'mouse 8-shaped hatching', 'zebrafish janus mutant', and 'nine-banded armadillo embryo', along with literature collected through day-to-day reading. The search was limited to articles in English, with no restrictions on publication date or species. For monochorionic MZ twins, ART cases and mouse experiments demonstrate evidence that a looser ICM in blastocysts has an increased chance of ICM separation. Physical forces facilitated by blastocoel formation or 8-shaped hatching are exerted on the ICM, resulting in monochorionic MZ twins. For dichorionic MZ twins, the classic model resembles artificial cloning of mouse embryos in vitro, requiring strictly controlled splitting forces, re-joining prevention, and proper aggregation, which allows the formation of two separate human blastocysts under physiological circumstances. In contrast, ART procedures involving the transfer of a single blastocysts after atypical hatching or vitrified-warmed cycles might lead to blastocyst separation. Differences in morphology, molecular mechanisms, and timing across various animal model systems for MZ twinning can impede this research field. As discussed in future directions, recent developments of innovative in vitro models of human embryos may offer promising avenues for providing fundamental novel insights into the cellular mechanisms of MZ twinning during human embryogenesis. Twin pregnancies pose high risks to both the fetuses and the mother. While single embryo transfer is commonly employed to prevent dizygotic twin pregnancies in ART, it cannot prevent the occurrence of MZ twins. Drawing from our understanding of the cellular mechanisms underlying monochorionic and dichorionic MZ twinning, along with insights into the genetic mechanisms, could enable improved prediction, prevention, and even intervention strategies during ART procedures. N/A.

Effects of high-normal fasting blood glucose on ART outcomes of frozen-thawed single blastocyst transfer in women with normal BMI.

This retrospective cohort study aims to investigate whether high-normal fasting blood glucose (FBG) affects assisted reproductive technology (ART) outcomes undergoing single blastocyst frozen-thawed embryo transfer (FET) cycles in women with normal body mass index (BMI). 944 women with normal BMI and FBG levels undergoing single blastocyst FET cycles were enrolled. Based on the median of FBG (4.97mmol/L, 1mmol/L = 18mg/dL), the subjects were categorized into the low-normal group (3.90 ≤ FBG ≤ 4.97 mmol/L, n = 472) and the high-normal group (4.97 < FBG < 6.10mmol/L, n = 472). Multivariable logistic regression and receiver operating characteristic (ROC) were used to analyze the relationship between high-normal FBG and ART outcomes. live birth rate (LBR). LBR was significantly lower in the high-normal group than in the low-normal group (36.8% vs. 45.1%, p = 0.010), and the miscarriage rate was considerably higher than that in the low-normal group (23.9% vs. 16.5%, p = 0.041). High-normal FBG of female was an independent predictor of live birth (adjusted OR:0.747, 95% CI: 0.541-0.963, p = 0.027) and miscarriage (adjusted OR:1.610, 95% CI: 1.018-2.547, p = 0.042). ROC analyses showed that the cut-off values of FBG (endpoints: live birth and miscarriage) were 5.07mmol/L, and 5.01mmol/L, respectively. In women with normal BMI, high-normal FBG is an independent risk factor for lower LBR and higher miscarriage rate in single blastocyst FET cycles. Attention to preconception FBG monitoring in this particular population may allow early intervention to improve ART outcomes.

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

P-429 Measuring serum progesterone levels on the day of a fresh blastocyst transfer is debatable as there is no evidence for correlation with ongoing pregnancy results

Abstract Study question Does serum progesterone (P4) level on the day of a fresh blastocyst transfer relate to ongoing pregnancy rate (OPR)? Summary answer OPR after a fresh single blastocyst transfer seems not to be associated with serum P4 level on the day of transfer. What is known already Several studies have suggested an optimal serum P4 threshold for embryo transfers in frozen embryo transfer cycles. However, for fresh embryo transfers, data are scarce and conflicting. Study design, size, duration A retrospective single-center cohort study was performed on 598 complete data cycles, retained out of 631 consecutive fresh single blastocyst transfer cycles. Data were collected from patients undergoing a fresh IVF/ICSI cycle with autologous oocytes at a tertiary fertility center between June 2022 and August 2023. Participants/materials, setting, methods A total of 482 unique patients underwent one or more single fresh blastocyst transfers using micronized vaginal progesterone (MVP) 800mg BID for luteal phase support starting day after oocyte retrieval. Serum P4 levels were determined on day of transfer. The primary endpoint was OPR, positive hCG-test and early pregnancy loss (EPL) were secondary endpoints. Unadjusted and adjusted generalized estimating equations (GEE) assessed P4 level association with the endpoints, using an exchangeable working correlation matrix. Main results and the role of chance No association was identified between P4 levels on day of transfer and OPR after accounting for maternal age, blastocyst quality, P4 and estradiol level at last ultrasound, BMI and endometrial thickness. Data were grouped according to 10/50/90 and 25/50/75 percentiles, resulting in groups &amp;lt; = or &amp;gt; 27ng/ml and &amp;lt; = or &amp;gt; 40ng/ml, with omission of 90th and 75th percentile groups due to right-skewed distribution. With serum P4 levels higher than 40ng/ml, the probability of a positive hCG-test significantly increased (OR 1.79, CI 1.11-2.91; p = 0.018). No significant difference was observed in patients with serum P4 &amp;lt; = or &amp;gt; 27ng/ml (OR 1.23, CI 0.66-2.30; p = 0.506). Regarding OPR, no significant differences were observed when comparing patients with serum P4 &amp;lt; = or &amp;gt; 27/ng/ml or &amp;lt; = or &amp;gt; 40ng/ml (OR 0.88, CI 0.42-18.85; p = 0.736 and OR 1.41, CI 0.83-2.37; p = 0.203, respectively). Moreover, EPL did not significantly differ between serum P4 level groups (OR 1.93, CI 0.61-6.13; p = 0.265 and OR 1.2, CI 0.51-2.84; p = 0.674). Age (p &amp;lt; 0.001) and embryo quality (p &amp;lt; 0.001) are significantly related with OPR. Additionally, late follicular progesterone levels and OPR are significantly associated (OR 2.39, CI 1.16-4.95 in patients with P4 &amp;lt; = or &amp;gt; 27/ng/ml and OR 2.21, CI 1.07-4.55 in patients with &amp;lt; =40ng/ml and &amp;gt;40ng/ml). Limitations, reasons for caution Limitations include the retrospective design and the lack of live birth outcome data. Progesterone levels exceeding 60 ng/ml were not further analyzed to their precise value but grouped as 60 plus which did not allow to identify potential detrimental effects of very high P4 levels on treatment outcome. Wider implications of the findings Our data suggest that measuring P4 on the day of a single blastocyst transfer with MVP luteal phase support may not be indicative of OPR or the risk of EPL. This raises questions regarding the necessity for routine P4 measurements as well as the development of rescue strategies. Trial registration number ONZ-2023-0628

P-123 Comparison of the performance of 3 models (iDAScore v1.0, KIDScore D5 v3, and NEQsi score) for predicting pregnancy after single blastocyst transfer

Abstract Study question What is the respective performance of an AI model, a morphokinetic model and an embryo morphology model for the prediction pregnancy after single blastocyst transfer? Summary answer KIDScore™ D5 v3, NEQsi score, and iDAScore™ v1.0 demonstrated similar performance in predicting biochemical pregnancy, clinical pregnancy, and live birth. What is known already Blastocyst selection for transfer currently mostly relies on Gardner’s morphological classification, which suffers from relatively limited predictive performance and interoperator variability. Both morphokinetic scores and the development of AI tools raised hope for improved embryo quality assessment in IVF. The NEQsi score is a very recently published digital transcription of the Gardner classification, allowing easier data categorization and comparison with other scores / models. The respective performance of these models / scores has hardly been reported up to now. Studying this in a setting with systematic single blastocyst policy allows avoiding biases related to patients’ selection. Study design, size, duration This is a retrospective monocentric study conducted in 2020-2022 on single blastocyst transfers after culture in a time-lapse incubator (Embryoscope©). All embryos with a known clinical outcome after fresh or frozen transfer and with KIDScore™ D5 v3, NEQsi score, and iDAScore™ v1.0 were included, regardless of the ART technique. Participants/materials, setting, methods All patients gave their consent for anonymous analysis of their clinical data. All scores were compared by conducting a One-way ANOVA test followed by a non-parametric Kruskal-Wallis test. A ROC curve was calculated for the prediction of both biochemical, clinical pregnancy and live birth. Main results and the role of chance 1888 single blastocyst transfers were performed in 1223 patients, 907 resulting in a biochemical pregnancy, 626 in a clinical pregnancy, and 495 in a live birth. The mean values were 7.00 (± 1.64) for the KIDscore, 7.99 (± 1.30) for the NEQsi, and 8.50 (± 1.00) for the iDAscore. The mean score values were significantly different between groups according to positive or negative clinical outcome (p &amp;lt; 0.0001 for all). The ROC curves showed that all 3 scores are predictive of a biochemical pregnancy (AUC KIDScore = 0.62; AUC NEQsi = 0.63; AUC iDAScore = 0.60), clinical pregnancy (AUC KIDScore = 0.64; AUC NEQsi = 0.65; AUC iDAScore = 0.61), and a live birth (AUC KIDScore = 0.62; AUC NEQsi = 0.63; AUC iDAScore = 0.60). These AUCs were not significantly different, and none of these scores appeared to be superior to the others in predicting live birth after single blastocyst transfer. Limitations, reasons for caution The retrospective and monocentric design calls for caution when generalizing these results. Wider implications of the findings The respective relevance of these scores in shortening time to pregnancy by ranking usable embryos within a cohort should be considered in further studies. Trial registration number not applicable