Frozen-thawed Blastocyst Transfer Research Articles

Impact of double trophectoderm biopsy on reproductive outcomes following single euploid blastocyst transfer

ObjectivesTo study the effect of double trophectoderm biopsy on clinical outcomes following single euploid blastocyst transfer. Study designRetrospective cohort study of 2046 single euploid frozen-thawed blastocyst transfers from January 2015 to June 2022 in a single centre.All patients undergoing a frozen-thawed embryo transfer (FTET) cycle with euploid blastocysts, biopsied for any indication, were included. The outcomes were compared for blastocysts which were biopsied and vitrified once (Group 1, n = 1684), biopsied once but vitrified twice (Group 2, n = 312) and biopsied and vitrified twice (Group 3n = 50). We adjusted for confounders and performed subgroup analysis for PGT-A, PGT-M and PGT-SR cycles. The primary outcome was live birth rate. Secondary outcomes included pregnancy, clinical pregnancy, birthweight and sex ratio. ResultsAfter adjusting for confounders (previous failed euploid implantations, embryo quality and day of biopsy), embryos which were biopsied twice had lower OR for clinical pregnancy (0.48, CI 0.26–0.88, p = 0.019) and for live birth (0.50 CI 0.27–0.92, p = 0.025) compared to controls. Embryos which were biopsied once but vitrified twice had no different ORs for all reproductive outcomes compared to controls. No significant difference was observed for neonatal birthweight or sex ratio amongst the three groups. This is a retrospective single centre study with inherent bias and results may not be transferable to all settings. ConclusionThis study is the largest to date assessing the outcomes of FTET cycles following double trophectoderm biopsy. The results are in keeping with the existing literature and can be incorporated into patient counselling. Whilst double biopsy seems to adversely impact LBR, it is only one of the many factors that can affect success rates. The subfertility background and embryo characteristics should not be overlooked. This study provides reassuring evidence since double biopsied embryos still result in live births with no difference in sex ratio or birthweight. However, long term follow up of the off-springs is lacking and should be reported in future studies.

Female smoking does not affect live birth rate after frozen thawed blastocyst transfer cycle

PurposeThe development of vitrification and blastocyst culture have recently led to a rapidly growing number of single frozen thawed blastocyst transfer (FBT) cycles worldwide. Although the impact of female smoking on spontaneous fertility is well established, its effect on assisted reproductive technologies (ART) outcome is still controversial, and no study has specifically evaluated its effect on FBT cycles’ outcome. MethodsThis retrospective study was conducted in all consecutive FBT cycles conducted between 2012 and 2021 in a single University-based ART centre. Endometrial preparation was standard and based on hormonal replacement therapy. One or two blastocysts were transferred according to couple's history and embryo quality. Female smoking status was recorded for each cycle, and the association between female smoking status and Live Birth Rate (LBR) after FBT cycle was evaluated with univariate and multivariate analysis. ResultsA total of 1537 FBT cycles performed in non-smoking women and 397 FBT cycles performed in smoking women were included in the analysis. No independent association between female smoking status and LBR in FBT cycles was found after logistic regression (OR=1.07 [0.79–1.45], p = 0.649). ConclusionOur study suggests that female smoking might not impair endometrial receptiveness in non-stimulated FBT cycles. Further studies should nevertheless consider assessing more precisely the current smoking exposure.

Effect of post-vitrification cryopreservation duration on singleton birth-weight in frozen-thawed blastocysts transfer cycles.

This study aimed to explore the effect of cryopreservation duration after blastocyst vitrification on the singleton birth-weight of newborns to assess the safety of long-term preservation of frozen-thawed blastocyst transfer (FBT) cycles. This was a retrospective observational study conducted at the Gynecological Endocrinology and Assisted Reproduction Center of the Peking Union Medical College Hospital. Patients who gave birth to singletons between January 2006 and December 2021 after undergoing FBT cycles were included. Five groups were formed according to the duration of cryopreservation of embryos at FBT: Group I included 274 patients with a storage time < 3 months. Group II included 607 patients with a storage time of 3-6 months. Group III included 322 patients with a storage time of 6-12 months. Group IV included 190 patients with a storage time of 12-24 months. Group V included 118 patients with a storage time of > 24 months. Neonatal outcomes were compared among the groups. Multivariate linear regression analysis was performed to evaluate birth-weights and other birth-related outcomes. A total of 1,511 patients were included in the analysis. The longest cryopreservation period was 12 years. The birth-weights of neonates in the five groups were 3344.1 ± 529.3, 3326.1 ± 565.7, 3260.3 ± 584.1, 3349.9 ± 582.7, and 3296.7 ± 491.9 g, respectively (P > 0.05). The incidences of preterm birth, very preterm birth, low birth-weight, and very low birth-weight were similar in all groups (P > 0.05). The large-for-gestational-age and small-for-gestational-age rates did not differ significantly among the groups (P > 0.05). After adjusting for confounding factors that may affect neonatal outcomes, a trend for an increased risk of low birth-weight with prolonged cryopreservation was observed. However, cryopreservation duration and neonatal birth-weight were not significantly correlated (P > 0.05). The duration of cryopreservation after blastocyst vitrification with an open device for more than 2 years had no significant effect on the birth-weight of FBT singletons; however, attention should be paid to a possible increase in the risk of low birth-weight.

Which factors affect the live birth outcome of the first single euploid frozen-thawed blastocyst transfer in couples with balanced chromosomal translocations?

The objective of this study is to investigate the factors that influence the live birth rate (LBR) of the first single euploid frozen-thawed blastocyst transfer (FBT) cycles after preimplantation genetic testing for structural rearrangements (PGT-SR) in couples with balanced chromosomal translocations (BCT). Single center, retrospective and observational study. A total of 336 PGT-SR and the first single euploid FBT cycles between July 2016 and December 2022 were included in this study. The patients were divided into two groups according to the live birth outcomes. The parameters of the study population, controlled ovarian stimulation cycles, and FBT cycles were analyzed. Multivariable binary logistic regression was performed to find the factors that affected the LBR. The percentage of blastocysts at developmental stage Day 5 compared to Day 6 (51.8% vs. 30.8%; P<0.001) and with morphology ≥BB compared to <BB (49.7% vs. 32.2%; P=0.001) was significantly different between the group that resulted in live births (n=193) and the group that did not (n=143). The results of the multivariable binary logistic regression analysis indicated that the developmental stage (adjusted OR: 2.068, 95%CI 1.291-3.313; P=0.003) and morphology (adjusted OR: 1.697, 95%CI 1.039-2.773; P=0.035) of the blastocyst were significantly correlated with live birth. Patients with blastocysts that reached the developmental stage at Day 5 and had a morphology of ≥BB had a higher likelihood of having a live birth. The developmental stage and morphology of blastocyst affect the live birth outcome of the first single euploid FBT in BCT carriers undergoing PGT-SR.

Sex ratio shift after frozen single blastocyst transfer in relation to blastocyst morphology parameters

The sex ratio shift was observed in peoples who underwent ART treatment. Moreover, there is limited evidence on differences in sex ratio between single frozen-thawed blastocyst morphology, insemination type and transfer days. So further research is needed in this area with regard to factors possibly affecting the sex ratio. Retrospective study based on multicenter including two large assisted reproduction centers in Shanghai and Wuhan in China. A total of 6361 singleton delivery offspring after frozen-thawed blastocyst transfer. Propensity score weighting and logistic regression models were used to estimate the associations between blastocyst morphology grading and child sex ratio. The main outcome measures is singleton sex ratio. In our study, the primary outcome measure was sex ratio which was calculated as the proportion of male newborns among all live births. Higher quality blastocysts resulted in a higher sex ratio than single poor-quality frozen-thawed blastocyst transfer. Among the three blastocyst morphological parameters of trophectoderm (TE), Grade A and B were significantly associated with a higher sex ratio than Grade C. The similar trend was observed in both IVF and ICSI treated subgroups. As compared with expansion (4 + 3), expansion degree 6 achieved a higher sex ratio in overall populations and IVF treated subgroup. Transferring blastocysts of day 6 had the highest sex ratio both in IVF group and ICSI group. A 6.95% higher sex ratio in transferring blastocysts of day 5 in IVF group than those in ICSI group. No significant association between inner cell mass degree and sex ratio was observed. However, as compared with IVF treatment, all morphology parameters achieved the similar or the biased sex ratio favoring female in ICSI treated subgroup. Quality of blastocysts was positively associated with sex ratio. TE score and expansion degree rather than ICM were significantly associated with sex ratio at birth. ICSI treatment promotes the biased sex ratio favoring female.

Single versus double blastocyst transfer in first and second frozen-thawed embryo transfer cycle in advance-aged women: a two-center retrospective cohort study.

The present evidence is deficient for the trade-offs between the pros and cons of single blastocyst transfer (SBT) versus double blastocyst transfer (DBT) in frozen-thawed embryo transfer cycles for women in advanced reproductive age, especially in the second cycle. The current study aimed to investigate the impact of transferred blastocyst numbers on pregnancy outcomes in the first and second embryo transfer for women ≥ 35 years. This was a retrospective cohort study including 1284 frozen-thawed blastocyst transfer (FBT) cycles from two reproductive centers. We analyzed the pregnancy outcomes after SBT and DBT in the first and second FBT cycles. Moreover, stratified analysis was conducted by maternal age. In the first FBT cycle, the LBR was higher in the DBT group than that in the SBT group [52.3% vs. 33.9%; adjusted odds ratio (aOR), 1.65; 95% confidence interval (CI), 1.26-2.15, P < 0.001]. However, the LBR of the DBT group showed no remarkable difference compared with that of the SBT group in the second cycle of FBT (44.3% vs. 33.3%; aOR, 1.30; 95% CI, 0.81-2.08; P = 0.271). Furthermore, stratified analysis by age showed a higher LBR for the DBT group than the SBT group in patients aged 38-42 years (43.1% vs. 33.9%; aOR, 2.27; 95% CI, 1.05-4.90; P = 0.036). The present study demonstrated that the SBT regimen is a better choice for both, the first and second frozen-thawed embryo transfer cycles, for women aged 35-37 years. Additionally, the DBT regimen is still recommended to achieve a high LBR in women aged 38-42 years in the second FBT cycle. These findings may be beneficial for deciding the embryo transfer regimens in women of advanced reproductive age.

Effect of development speed and quality of blastocyst on singleton birthweight in single frozen-thawed blastocyst transfer cycles.

Assisted reproductive technology (ART) has revolutionized infertility treatment, leading to a surge in ART-conceived children. Despite its success, ART-born offspring face higher risks of preterm birth (PTB), low birth weight (LBW), and small for gestational age (SGA). The mechanisms behind these outcomes remain unclear, partly attributed to multiple embryo transfers. Recent advancements advocate single blastocyst transfers for improved outcomes. However, the influence of blastocyst quality and development speed on neonatal outcomes is underexplored. This study investigated whether blastocyst development speed and quality affect singleton birthweight when the blastocyst is selected for single frozen-thawed blastocyst transfer (FBT). Data from patients who performed an FBT cycle at our center from July 2011 to June 2021 were collected and analyzed. Based on the inclusion and exclusion criteria, 420 single FBT cycles were assessed. The women were divided into four groups, Group A (day 5, good-quality blastocysts), Group B (day 5, non-good-quality blastocysts), Group C (day 6, good-quality blastocysts), and Group D (day 6, non-good-quality blastocysts) according to the developmental speed and quality of the transferred blastocyst. The birthweight was relatively the highest in Group A, which developed rapidly and transferred good quality blastocysts. However, no significant difference existed among the groups (P>0.05). The prevalence of premature birth (PTB), low birth weight (LBW), very low birth weight (VLBW), or high birth weight (HBW) was similar among the four groups (P > 0.05). No correlation existed between birth weight and blastocyst development speed or quality after adjusting for possible confounders (P > 0.05 respectively). However, the difference in the proportion of males born among the four groups was significant, especially in Group D, which was significantly lower than that in Group A (adjusted odds ratio = 0.461, 95% confidence interval: 0.230-0.921, P< 0.05). This retrospective cohort study suggests that the combined effect of blastocyst development speed and quality on neonatal birthweight is insignificant. The transfer of slow-growing, non-good-quality blastocysts increases the chance of a female baby being born.

#276 : Impact of Previous Cesarean Delivery on Pregnancy and Neonatal Outcomes of Subsequent In Vitro Fertilization/Intracytoplasmic Sperm Microinjection and Single Frozen-Thawed Embryo Transfer

Background and Aims: Cesarean delivery (CD) rates continue to rise worldwide. Prior studies have indicated that CD is associated with not only various gynaecological symptoms and obstetric complications but also lower probability of subsequent fertility. However, the recognition about impact of CD on clinical outcomes in subsequent IVF/ICSI-FET is very limited. The purpose was to investigate the effects of previous CD on pregnancy and neonatal outcomes in single frozen-thawed embryo transfer (FET) cycles so that women with a previous cesarean delivery can be given detailed fertility counseling during the ART process. Methods: This is a large retrospective cohort study including a total of 5,750 patients who desired to transfer single vitrified-thawed blastocyst from the same oocyte retrieval cycle as their last live birth between January 2011 and January 2021 in a center for reproductive medicine in Shandong, China, comprising FET cycles of 3,853 previous single CD and 1,897 previous single vaginal delivery (VD). Results: Women with a previous CD had significantly lower rates of biochemical pregnancy (64.52% vs. 71.48% before propensity score matching (PSM), P&lt;0.001; and 65.58% vs. 71.49% after PSM, P&lt;0.001), clinical pregnancy (58.16% vs. 65.79% before PSM, P&lt;0.001; and 59.22% vs. 66.17% after PSM, P&lt;0.001) and live birth (48.17% vs. 55.82% before PSM, P&lt;0.001; and 49.29% vs. 56.10% after PSM, P&lt;0.001) than those with a previous VD. Meanwhile, the CD rate was significantly higher in the CD group (97.85% vs. 18.53% before PSM, P&lt;0.001; and 98.02% vs. 20.51% after PSM, P&lt;0.001). The rates of multiple pregnancy, miscarriage, ectopic pregnancy, multiple live birth, labor complications and preterm and neonatal outcomes were comparable between the two groups. Conclusion: Compared to VD, a previous CD is associated with a significant reduction in the rates of biochemical pregnancy, clinical pregnancy and live birth in patients undergoing subsequent single frozen-thawed blastocyst transfer.

Chronic Infection in Recurrent Pregnancy Loss

In the present study, the effects of chronic endometritis (CE) on implantation and pregnancy outcomes, the effects of CE on endometrial function, and the effects of progesterone as a treatment for CE were examined. It was found that the pregnancy rate and live birth rate were significantly lower in CE patients in a prospective study. When patients were diagnosed with CE, not only were the pregnancy rate and live birth rate significantly lower, but the miscarriage rate was higher in a retrospective study. Next, the presence of chronic deciduitis (CD) in the miscarriage specimen was determined in patients diagnosed with or without CE before pregnancy. CD was determined when the presence of clusters of plasma cells or five or more plasma cells in the decidua. CD was found in more than half of CE, but not found in Non-CE before pregnancy. In in vitro study, we revealed the secretions of TNF[Formula: see text], IL1[Formula: see text], and IL6 per cell were significantly higher in CE. The rate of Th1 was greater and it of Th2 was significantly lower in CE, and those of Tregs and Th17 were not different. Both PRL and IGFBP1, decidualized markers, showed significant decreases in secretion with CE, and conversely, the number of cells was significantly higher in the CE group. Based on the results of bench studies, we hypothesized that an altered administration route and increased dosage of progestogen may improve clinical outcomes. The clinical outcomes of patients who underwent single frozen-thawed blastocyst transfer were examined for each hormone replacement therapy. It was found that using a progesterone vaginal suppository in combination with an oral progestin for hormone replacement improved the live birth rate, but not the miscarriage rate in CE patients when compared with using an oral progestin alone.

Interpregnancy Interval After Clinical Pregnancy Loss and Outcomes of the Next Frozen Embryo Transfer

The optimal interpregnancy interval (IPI) after a clinical pregnancy loss (CPL) remains controversial. Few studies have addressed the role of the IPI after a preceding CPL during in vitro fertilization (IVF) treatment. To evaluate the association between different IPI lengths after a preceding CPL and pregnancy outcomes of the next frozen embryo transfer (FET). This retrospective cohort study was conducted using data from the Center for Reproductive Medicine of Shandong University in China. The study included women who underwent frozen-thawed blastocyst transfer between July 1, 2017, and June 30, 2022, within 1 year after a preceding CPL during IVF treatment. Follow-up for pregnancy outcomes was completed for all participants on March 31, 2023. Data analysis was performed from April to May 2023. Interpregnancy interval length was classified as less than 3 months, 3 to less than 6 months, or 6 to 12 months. Outcomes included live birth, conception, clinical pregnancy, pregnancy loss, preterm birth, small or large for gestational age, and low birth weight. Multivariable logistic regression analysis was conducted to evaluate the association between IPI and pregnancy outcomes by adjusted odds ratios (AORs). This study included 2433 women (mean [SD] age, 31.8 [4.6] years) who received IVF treatment. There were 338 women (13.9%) with an IPI of less than 3 months, 1347 (55.4%) with an IPI of 3 to less than 6 months, and 748 (30.7%) with an IPI of 6 to 12 months. The median (IQR) IPI lengths for the 3 groups were 77 (65-85), 128 (109-152), and 234 (202-288) days, respectively. Compared with an IPI of 6 to 12 months, shorter IPIs (<3 and 3 to <6 months) were associated with decreased odds of clinical pregnancy (AOR, 0.70 [95% CI, 0.53-0.92] and 0.79 [0.65-0.95]), live birth (AOR, 0.64 [95% CI, 0.48-0.85] and 0.74 [0.61-0.90]), and healthy live birth (AOR, 0.63 [95% CI, 0.46-0.87] and 0.79 [0.64-0.98]). Compared with women with an IPI of 6 to 12 months, women with shorter IPIs (<3 and 3 to <6 months) had a higher risk of total pregnancy loss (AOR, 1.87 [95% CI, 1.31-2.67] and 1.29 [1.00-1.66], respectively). The results of this study suggest that delaying the next FET for at least 6 months after a preceding CPL was associated with beneficial pregnancy outcomes, considering that a decreased likelihood of achieving clinical pregnancy and live birth was observed among women with shorter IPIs. Further prospective studies are needed to confirm these findings.

Effectiveness of atosiban in women with previous single implantation failure undergoing frozen-thawed blastocyst transfer: study protocol for a randomised controlled trial

BackgroundUterine contractions may interfere with embryo implantation in assisted reproductive technology. To reduce these contractions and improve success rates, the oxytocin antagonist atosiban has been suggested for administration during embryo...

Effect of blastocyst shrinkage on assisted reproductive outcomes: a retrospective cohort study describing a new morphological evaluation of blastocyst pre-vitrification and post-warming

BackgroundThe failure of frozen-thawed blastocysts to re-expand adequately within a few hours after warming has been reported to have a negative impact on assisted reproductive technology (ART) outcomes. However, the extent to which this failure truly affects ART outcomes has not yet been presented in a manner that is easily understandable to medical practitioners and patients. This study aimed to assess the effects of blastocyst shrinkage on ART outcomes and determine a more effective morphological evaluation approach for use in clinical settings.MethodsThis retrospective observational cohort study of frozen-thawed blastocyst transfer cycles was conducted from April 2017 to March 2022. Overall, 1,331 cycles were eligible for inclusion, of which 999 were good-quality blastocysts (GQB) and 332 were non-good-quality blastocysts (non-GQB). All frozen-thawed blastocyst transfer cycles performed during the specified study period were included in the study. Exclusion criteria were established to mitigate potential sources of bias as these cycles could impact implantations. We calculated rates and age-adjusted odds ratios of implantation, clinical pregnancy, ongoing pregnancy, and live birth of the re-expansion group, which showed sufficient expansion, and shrinkage group, which showed insufficient expansion. We also calculated the implantation, clinical pregnancy, ongoing pregnancy, and live birth rates of the re-expansion and shrinkage groups for each morphological scoring system parameter.ResultsA reduced ART outcome was observed with use of blastocysts with shrinkage after vitrification/warming. The age-adjusted odds ratios for implantation, clinical pregnancy, ongoing pregnancy, and live birth were lower in the shrinkage group than in the re-expansion group.ConclusionsThis study examined the adverse effect of blastocyst shrinkage after warming and recovery culturing on reproductive outcomes in a clinically useful manner by retrospectively examining a substantial number of frozen-thawed embryo transfer cycles. The study findings can possibly reduce concerns regarding over- or under-estimation of blastocyst implantation by allowing providers and patients to refer to the data.

Methods to improve frozen-thawed blastocyst transfer outcomes- the IVF laboratory perspective

During the last few years, the number of frozen-thawed embryo transfer cycles (FET) significantly increased due to the universal application of more efficient cryopreservation techniques in the IVF laboratory and the improved survival rates of blastocyst stage embryos and the wide implementation of “freeze all” IVF cycles to prevent OHSS, or for preimplantation genetic testing for aneuploidy (PGT-A). Blastocyst cryopreservation allows single embryo transfers to reduce the rate of multiple pregnancies and improve perinatal outcomes. There is no consensus regarding the optimal laboratory protocol for blastocyst cryopreservation, and research is ongoing for its amelioration. This review summarizes different laboratory methods that may improve frozen-thawed blastocyst embryo transfer outcomes, alone or in combination. Some of the techniques relate to embryo survival; some of them work on endometrial receptivity.

Dynamic peripheral blood microRNA expression landscape during the peri-implantation stage in women with successful pregnancy achieved by single frozen-thawed blastocyst transfer.

What are the dynamic expression features of plasma microRNAs (miRNAs) during the peri-implantation period in women with successful pregnancy via single frozen-thawed blastocyst transfer? There is a significant change in the plasma miRNA expression profile before and after blastocyst transfer, during the window of implantation. The expression of miRNAs in peripheral blood has indicative functions during the peri-implantation period. Nevertheless, the dynamic expression profile of circulating miRNAs during the peri-implantation stage in women with a successful pregnancy has not been studied. Seventy-six women treated for infertility with a single frozen-thawed blastocyst transfer in a natural cycle were included in this study. Among them, 57 women had implantation success and a live birth, while 19 patients experienced implantation failure. Peripheral blood samples were collected at five different time points throughout the peri-implantation period, including D0 (ovulation day), D3, D5, D7, and D9 in this cycle of embryo transfer. The plasma miRNAs in women with blastocyst transfer were isolated, sequenced, and analyzed. Peripheral blood samples were collected in EDTA tubes and stored at -80°C until further use. miRNAs were isolated from blood, cDNA libraries were constructed, and the resulting sequences were mapped to the human genome. The plasma miRNAs were initially analyzed in a screening cohort (n = 34) with successful pregnancy. Trajectory analysis, including a global test and pairwise comparisons, was performed to detect dynamic differentially expressed (DE) miRNAs. Fuzzy c-means clustering was conducted for all dynamic DE miRNAs. The correlation between DE miRNAs and clinical characteristics of patients was investigated using a linear mixed model. Target genes of the miRNAs were predicted, and functional annotation analysis was performed. The expression of DE miRNAs was also identified in a validation set consisting of women with successful (n = 23) and unsuccessful (n = 19) pregnancies. Following small RNA sequencing, a total of 2656 miRNAs were determined as valid read values. After trajectory analysis, 26 DE miRNAs (false discovery rate < 0.05) were identified by the global test, while pairwise comparisons in addition identified 20 DE miRNAs. A total of seven distinct clusters representing different temporal patterns of miRNA expression were discovered. Nineteen DE miRNAs were further identified to be associated with at least one clinical trait. Endometrium thickness and progesterone level showed a correlation with multiple DE miRNAs (including two of the same miRNAs, hsa-miR-1-3p and hsa-miR-6741-3p). Moreover, the 19 DE miRNAs were predicted to have 403 gene targets, and there were 51 (12.7%) predicted genes likely involved in both decidualization and embryo implantation. Functional annotation for predicted targets of those clinically related DE miRNAs suggested the involvement of vascular endothelial growth factor and Wnt signaling pathways, as well as responses to hormones, immune responses, and cell adhesion-related signaling pathways during the peri-implantation stage. The raw miRNA sequence data reported in this article have been deposited in the Genome Sequence Archive (GSA-Human: HRA005227) and are publicly accessible at https://ngdc.cncb.ac.cn/gsa-human/browse/HRA005227. Although the RNA sequencing results revealed the global dynamic changes of miRNA expression, further experiments examining the clinical significance of the identified DE miRNAs in embryo implantation outcome and the relevant regulatory mechanisms involved are warranted. Understanding the dynamic landscape of the miRNA transcriptome could shed light on the physiological mechanisms involved from ovulation to the post-implantation stage, as well as identifying biomarkers that characterize stage-related biological process. The study was funded by the Major clinical research project of Tangdu Hospital (2021LCYJ004) and the Discipline Platform Improvement Plan of Tangdu Hospital (2020XKPT003). The funders had no influence on the study design, data collection, and analysis, decision to publish, or preparation of the article. There are no conflicts of interest to declare.

Influence of maternal age on the birthweight of infants delivered from frozen-thawed blastocyst transfer cycles.

The aim of this study was to investigate whether maternal age had an effect on the birthweight of singletons delivered from frozen-thawed blastocyst transfer (FBT) cycles. A total of 1203 FBT cycles occurring between July 2011 and June 2021 at a single centre were retrospectively analysed. Based on the maternal age at FBT, the patients were divided into four groups: <30, 30-34, 35-37, and ≥38 years of age. Main outcomes measured included singleton birthweights, preterm births, large-for-gestational-age (LGA) and small-for-gestational-age (SGA) live births among the groups. There was no significant difference in birth weight among the four groups, while the highest birth weight was found in the <30 years group. The incidence of very preterm births and very low birth weights demonstrated an increasing trend with age; on the contrary, the incidence of preterm births, low birth weight (LBW), high birth weight and LGA and SGA live births gradually decreased with increasing age, but these differences were not statistically significant among groups (P>0.05, respectively). Although the proportion of females was lower than that of males, the difference was not statistically significant among the groups. After adjusting for possible confounders, maternal age was found to have no effect on adverse neonatal outcomes in the regression analyses (P>0.05). Birthweight in singleton births from FBT was not affected by maternal age.

Adverse maternal and neonatal outcomes of preimplantation genetic testing with trophectoderm biopsy: a retrospective cohort study of 3373 intracytoplasmic sperm injection single frozen-thawed blastocyst transfer cycles.

To investigate whether trophectoderm biopsy increases the risk of adverse maternal and neonatal outcomes in intracytoplasmic sperm injection (ICSI) single frozen-thawed blastocyst transfer cycles. This respective cohort study enrolled 3373 ICSI single frozen-thawed blastocyst transfer cycles with and without trophectoderm biopsy. Statistical methods including univariate logistic regression analysis, multivariate logistic regression analysis, and stratified analyses were performed to explore the impact of trophectoderm biopsy on adverse maternal and neonatal outcomes. The rates of adverse maternal and neonatal outcomes were comparable between the two groups. Univariate analysis showed that the live birth rate (45.15% vs. 40.75%; P = 0.010) in the biopsied group was statistically higher than that in the unbiopsied group, and the rates of miscarriage (15.40% vs. 20.00%; P = 0.011) and birth defects (0.58% vs. 2.16%; P = 0.007) were statistically lower in the biopsied group. After adjusting for confounding factors, the rates of miscarriage (aOR = 0.74; 95% CI = 0.57-0.96; P = 0.022) and birth defects (aOR = 0.24, 95% CI = 0.08-0.70, P = 0.009) in the biopsied group were significantly lower than those in the unbiopsied group. Stratified analyses showed that the birth defects rate after biopsy was significantly reduced in the subgroups of age < 35years old, BMI ≥ 24kg/m2, artificial cycle with downregulation, poor-quality blastocysts, and Day 5 poor-quality blastocysts. Preimplantation genetic testing (PGT) with trophectoderm biopsy does not increase the risk of adverse maternal and neonatal outcomes in ICSI single frozen-thawed blastocyst transfer cycles, and PGT can effectively reduce the rates of miscarriage and birth defects.

P-192 Blastocyst collapse during embryonic development is a marker of low pregnancy potential, independent of other blastocyst evaluation criteria

Abstract Study question Is evaluation of blastocyst collapse during embryonic development an independent marker for ongoing pregnancy in single frozen-thawed blastocyst transfer cycles? Summary answer Collapse of blastocyst more than 20.4% of the area may be a marker of low ongoing pregnancy potential, independent of other evaluation criteria. What is known already Time-lapse monitoring revealed that a section of the extended trophectoderm (TE) is ruptured during development. This TE rupture causes an efflux of blastocoel fluid and a reduction in embryonic volume. This phenomenon is described as collapse. Several studies have reported that the collapse results in a low clinical and ongoing pregnancy potential for the blastocyst. However, the collapsed blastocysts were associated with poor morphological quality. Previous studies have not evaluated whether collapse is an independent predictor of pregnancy based on other blastocyst evaluation criteria. Therefore, it is necessary to determine whether blastocyst collapse is an independent predictor of ongoing pregnancy. Study design, size, duration This retrospective, single-center study was conducted at the TAKAHASHI WOMEN'S CLINIC from January, 2018 to December, 2020. All blastocysts were derived from the ICSI cycles. Time-lapse monitoring using Embryoscope + (Vitrolife) was used to observe the presence and degree of collapse. The degree of collapse was calculated from the embryonic volume at the maximum expansion and the lowest volume after collapse. We analyzed the relationship between 904 cycles of single vitrified-warmed blastocyst transfer and ongoing pregnancy. Participants/materials, setting, methods The ongoing pregnancy rates of collapsed and non collapsed blastocysts were compared using chi-squared test. The cut-off value of the degree of collapse for ongoing pregnancy was calculated using receiver operating characteristic (ROC) curve analysis. The effect of collapse above the cut-off value on ongoing pregnancy was examined using multivariate logistic regression analysis, including confounding factors (patient age, body mass index, inner cell mass (ICM) grade, TE grade, day of blastocyst formation, and expansion stage). Main results and the role of chance During the study period, 329 of the 904 transferred blastocysts exhibited collapse during time-lapse monitoring, and the degree of collapse ranged from 2.10% to 75.90%, with a median of 30.70%. In total, 575 transferred blastocysts were determined to be non collapsed. The mean patient age ( ± standard division) was 36.89 ± 4.77 years in the collapsed blastocyst group and 36.52 ± 4.42 years in the non collapsed blastocyst group (p = 0.151). The proportion of blastocysts with poor morphological grade (&amp;lt;BB ) was higher in the collapsed blastocysts group than in the non collapsed blastocysts group (32.5% vs. 17.91%, p &amp;lt; 0.0001). The ongoing pregnancy rate was significantly lower in the collapsed blastocysts group than in the non collapsed blastocysts group (45.4% vs. 34.0%, p = 0.0009). ROC curve analysis showed that the cut-off value for the degree of collapse for low pregnancy potential was 20.4%. Multivariate logistic analysis with confounding factors revealed that blastocyst collapse above the cut-off value (≥20.4%) had an effect on ongoing pregnancy (adjusted odds ratio: 0.53, 95% confidence interval: 0.34–0.82, p = 0.005) independent of ICM and TE grades, day of blastocyst formation, and expansion stage. Limitations, reasons for caution This retrospective study was conducted at a single fertility center. In addition, the analyzed blastocysts were derived only from the ICSI cycles. Therefore, it is necessary to analyze the effects of collapse in blastocysts derived from C-IVF cycles. Wider implications of the findings Our results demonstrate that ≥20.4% collapse may be an additional marker to consider when selecting blastocysts for transfer. If the blastocysts are of the same grade, it is better to select non collapsed embryos. Trial registration number not affect

P-620 First step for personalized luteal support in frozen-thaw embryo transfer: Understanding the factors associated with serum progesterone concentrations on embryo transfer day

Abstract Study question What factors determine serum progesterone (P) concentration on embryo transfer (ET) day after artificially prepared (AP) cycles receiving intramuscular progesterone (IM-P)? Summary answer Lower serum P concentrations on ET day in AP frozen-thaw cycles are associated with high body mass index(BMI) and low estradiol(E2) levels on ET day. What is known already Large sample sized studies reported low serum P levels on ET day in AP cycles related to low success rates. There are limited studies evaluating the pregnancy rates in patients with low serum P on ET day after the rescue doses. These studies included the patients who received vaginal P. There is no study evaluating rescue doses with low serum P concentration after IM-P. Common sense is that personalization of luteal phase support may increase the success rates. To adjust the P dosages, patient and cycle characteristics need to be analyzed for prediction of low serum P concentration. Study design, size, duration This retrospective cohort study conducted at Bahçeci Ankara IVF Center between November 2019 and February 2022. The study included 637 single or double frozen-thawed blastocyst transfers undergoing AP endometrium receiving 100 mg IM-P after incremental oestrogen treatment. Serum P concentrations were evaluated from the blood samples which were obtained between 117-119 hours after the first IM-P administration and 21±2 hours after last IM-P administration. Participants/materials, setting, methods A total of 637 patients, first frozen-thawed blastocyst ET cycles were analyzed. The mean age, BMI, duration of oestrogen treatment, ET day E2 and ET day P concentration of the study population were 31.9±5.1 years, 26.7 ±4.7 kg/m2, 13.9±1.3 days, 266.1±90.9 pg/ml and 30.2±9.3 ng/ml respectively. Correlation analysis for patient and cycle characteristics and serum P concentrations were evaluated. Multivariate linear regression analysis was performed to determine the independent factors. Main results and the role of chance The overall live birth rate in total study group was 50.7% (323/637). Female age, serum P concentrations on ET day, and number of embryos transferred were significantly associated with live birth. Bivariate correlation analysis revealed that ET day P concentrations were negatively correlated to BMI (r:-0.12, p: 0.002) and positively correlated to ET day E2 concentrations (r:0.14, p:0.001). However, no correlation to female age, causes of infertility, E2, P and LH concentrations on P administration day, duration of oestrogen treatment and presence or absence of GnRH agonist suppression. When a multivariate linear regression was performed to correct potential confounders, increasing BMI presented a negative correlation to ET day serum P concentrations (p = 0.003; 95% CI -0.384 to -0.079 ). On the contrary, significant positive correlations to ET day serum P concentrations were shown with ET day E2 levels (p = 0.01; 95% CI 0.003 to 0.018). Other patient and cycle characteristics were not found to be an independent factor for ET day P concentration. Limitations, reasons for caution The retrospective nature of the study is the main limitation. Only patients with IM-P were included therefore the results cannot be extrapolated to other P administration forms and needs to be validated. After determining the low serum P threshold in large sample size, the parameters should be re-evaluated. Wider implications of the findings Monitoring P levels and adjusting the doses of P administration (via personalization) may have a positive impact on outcome. Not only patient and cycle characteristics, also pharmacokinetic and pharmacogenetic studies are warranted to optimize luteal phase support. Personalization of the luteal phase can be achieved by this way. Trial registration number NA

P-201 Developmental analysis of blastocysts with blastomere exclusion during compaction and its relationship to pregnancy outcomes and preimplantation genetic testing for aneuploidy results

Abstract Study question What effects do blastocysts with blastomere exclusion during compaction have on embryo morphokinetics, morphology grade, genetic testing for aneuploidy (PGT-A) results, and pregnancy outcomes? Summary answer Blastocysts with blastomere exclusion leads to delay blastulation and poor morphology grade, but does not affect pregnancy outcomes and euploidy in PGT-A. What is known already It has been reported that aneuploid blastomeres are excluded during compaction, which is a mechanism for chromosome repair in blastocysts through the exclusion of aneuploid cells.Furthermore, in this phenomenon, it is known that the first cleavage of embryos is often abnormal, in which three or more cells originate from a single cell division event.However, this phenomenon has not been reported in the evaluation of embryo morphokinetics, artificial intelligence (AI) scores, or PGT-A results. Study design, size, duration In this retrospective study, we analyzed clinical medical reports at the Takahashi Women’s Clinic in Japan. We included 934 blastocysts cultured in a time-lapse incubator (EmbryoScope) after intracytoplasmic sperm injection (ICSI) from January 2018 to June 2021. Participants/materials, setting, methods Blastocysts cultured using a time-lapse incubator (EmbryoScope) after ICSI were classified into a control group (N = 515) with blastomere compaction or a BE group (N = 419) with blastomere exclusion during compaction. The first type of cleavage, AI score (IDAScore), embryo morphokinetics, and single frozen-thawed blastocyst transfer outcome were evaluated.Logistic regression analysis was performed to compare the two groups, considering patient age, blastocyst grade (Gardner classification), culture days, body mass index, and basal anti-Müllerian hormone level. Main results and the role of chance Comparing the control and BE groups, the first cleavage abnormality rate was 16.9% vs. 67.3% (P &amp;lt; 0.001), the percentage with good embryo grade (Gardner criteria ≧BB) was 93.4% vs. 61.0% (P &amp;lt; 0.001), and the mean score by AI analysis was 8.3 ± 1.3 vs. 6.4 ± 1.9 (P &amp;lt; 0.001), respectively. The BE group had a higher rate of abnormal cleavage and a significantly worse embryo grade and AI score than the control group.In the evaluation of embryo morphokinetics, the time to morula was 84.2 ± 7.0 h vs. 89.0 ± 8.5 h (P &amp;lt; 0.05) and time to blastocyst was 105.9 ± 9.4 h vs. 114.7 ± 11.4 h (P &amp;lt; 0.05). The BE group significantly delayed blastulation compared to the control group.The euploidy, mosaicism, and aneuploidy rates of PGT-A were 13.6% (9/66), 9.1% (6/66), and 77.3% (51/66) in the control group vs. 13.2% (5/38), 13.2% (5/38), and 73.7% (28/38) in the BE group, respectively. There was no significant difference in the PGT-A results between the two groups. Furthermore, the single-blastocyst transfer pregnancy rates (gestational sac with heart activity) in the control and BE groups were 47.1% (147/312) and 32.6% (60/184), respectively. Pregnancy rate was lower in the BE group, but was not significantly different from that of the control group. Limitations, reasons for caution The study was conducted at a single in vitro fertilization center. Embryo transfer results were based on ongoing pregnancies, while live birth data for all pregnancies are not yet available. Wider implications of the findings Although the BE group was graded worse, statistical analysis considering the grade showed no significant difference in PGT-A and pregnancy rates between the two groups.These results suggest that blastocysts with blastomere exclusion can be useful as transferable embryos if they grow to a transferable grade. Trial registration number not applicable

Comparison of clinical outcome between day 5 and day 6 single blastocyst transfers in cycles undergoing preimplantation genetic testing for aneuploidy

ObjectiveIn vitro fertilization (IVF) treatment has gradually adopted the practice of culturing embryos until the blastocyst stage on the D5 or D6 as the standard approach. PGT-A is commonly used in vitro fertilization (IVF). This study aimed to evaluate the clinical outcomes of frozen embryo transfers (FETs) using single blastocyst transfers (SBTs) on the fifth (D5) or sixth (D6) day of development in cycles that underwent preimplantation genetic testing for aneuploidy (PGT-A). Materials and methodsThe patients who had at least one euploid or mosaic blastocyst of good quality determined by PGT-A results and received single embryo transfer (SET) cycles were included in the study. In this study, the live birth rate (LBR) and neonatal outcomes were compared after the transfer of single biopsied D5 and D6 blastocysts in frozen embryo transfer (FET) cycles. ResultsA total of 527 frozen-thawed blastocyst transfer (FET) cycles (8449 biopsied embryos were analyzed). No significant difference in the implantation rate (IR), clinical pregnancy rate (CPR), and live birth rate (LBR) between the transfers of D5 and D6 blastocysts. Birth weight was the only perinatal outcome that showed a significant difference between the D5 and D6 groups. ConclusionThe study confirmed that the transfer of a single euploid or mosaic blastocyst, regardless of whether it was on the fifth (D5) or sixth (D6) day of development, can lead to promising clinical results.