Frozen-thawed Single Blastocyst Research Articles

P-153 Optimizing clinical outcomes in single vitrified-thawed blastocyst transfer cycles: impact of blastocyst re-expansion status

Abstract Study question is the blastocyst re-expansion status according to the thawing-transfer time interval related to the clinical outcomes in a single frozen-thawed blastocyst transfer cycles? Summary answer The post-thawing blastocyst shrinkage is linked to lower clinical outcomes, and minimizing the time between thawing and transfer optimizes outcomes especially for shrunken blastocysts. What is known already • A reduced ART outcome was observed with the use of shrunken post-warming blastocysts (Ito et al., 2023) • The spontaneous blastocyst shrinkage observed during in vitro embryonic development is considered as a negative prognosis factor for implantation (Sciorio et al., 2020) • The blastocyst’s re-expansion level after thawing proves to be the best post-thaw parameter for the prediction of live birth (The Vienna consensus., 2017. Ahlstrom et al., 2013). • The fast blastocele re-expansion seems to have a predictive value for implantation in frozen-thawed blastocyst transfer cycle (Shu et al., 2009). Study design, size, duration This was a retrospective study of 577 single frozen-thawed blastocyst transfer cycles from January 2022 to April 2023. Participants/materials, setting, methods Only B4 and B5 blastocyst quality obtained in day-5 were included in this study. The morphological characteristics were evaluated: after thawing (T0) and at Transfer time (TR). Blastocysts with 50% reduction of blastocele were classified “Shrunken”, the rest are “re-expanded”. and categorized into Group-1: re-expanded at T0 (n = 173); Group-2: shrunken at T0 and re-expanded at TR (n = 135); Group-3: shrunken at T0 and TR (n = 199). Statistical tests: chi-square, T-test and Mann-Whitney. (Statistical significance p < 0.05*). Main results and the role of chance Clinical outcomes of re-expanded blastocysts comparing to shrunken blastocysts at TR were respectively 42.21% versus 32.71% for pregnancy rate (PR) (p < 0.007),39.61% versus 30.48% for implantation rate (IR) (p < 0.02) and 35.71% versus 22.30% for life birth rate (LBR) (p < 0.004), a significantly higher outcomes were observed for re-expanded blastocysts. The miscarriage rate decreased from 25.00% to 9.23% (p < 0.001). The transfer of shrunken blastocysts in an interval of time within 1 hour or less comparing to more than 1 hour between T0 and TR showed the following results: PR = 40.82% versus 28.07% (p < 0.032), IR = 39.81% to 25.10%, (p < 0.02) and LBR = 26.53% versus 19.88% (p < 0.2). a significantly higher clinical outcomes were observed for shrunken blastocysts transferred within 1 hour or less. Group analysis: the PR, IR and LBR significantly increased for Group-1 comparing to Group 2. For Group-3, shrunken blastocysts at TR had the lower outcomes. (respectively p = 0.003; 0.017; 0.0002) Limitations, reasons for caution It is an ongoing retrospective observational study. Blastocysts with a low quality (B3 or less) were excluded from this study how limit our ability to extend the findings to low morphology degrees not covered by this research. Wider implications of the findings The management of frozen blastocyst transfers in IVF laboratories have to take into consideration in addition to the classic morphological evaluation, the blastocoele re-expansion state and the time interval between thawing and transfer to optimize the transfer outcomes. Trial registration number not applicable

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.

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.

#103 : The Clinical Outcomes of Lasered Assisted Hatching on Single Frozen-Thawed Blastocyst Cycle: A Retrospective, Observational Study

Background and Aims: The ultimate goal in assisted reproductive field is to achieve a pregnancy. For embryo to implant, embryo must be hatched from zona pellucida. Therefore, pregnancy began. Lasered assisted hatching (LAH) has been proposed as one of the interventions to increase the success rate, yet the efficacy remains uncertain. Hence, the aim of this study was to evaluate the effect of LAH toward clinical outcomes including clinical pregnancy, miscarriage, and ectopic pregnancy rate on single frozen-thawed blastocyst cycle. Method: A total of 1553 single frozen-thawed blastocyst cycles (LAH, n=116; non-LAH, n=1417) with patient’s mean age of 35 ± 0.06 were recruited from 2018 to 2022. The exclusion criteria were as follows: (a) gamete/embryo donation cycle and (b) PGT cases. Assisted hatching procedure was performed on LAH group with 1.46-[Formula: see text]m noncontact diode laser (LYKOSⓇ Laser) prior to embryo transfer. Result: The clinical pregnancy, miscarriage and ectopic pregnancy rates for LAH and non-LAH groups were 44.8% versus 48.7%, p = 0.35, 17.3% versus 16.2%, p = 0.86 and 0% versus 0.7%, respectively. No statistically significant difference was found on these clinical outcomes. Conclusion: This study demonstrated the use of LAH has no impact on the clinical outcomes and did not increase miscarriage and ectopic pregnancy. Therefore, it can be a useful tool for patients with recurrent implantation failure or embryo with thick zona pellucida.

#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.

Impact of Endometrial Preparation on the Maternal and Fetal Cardiovascular Variables of the First Trimester Combined Screening Test

The modality of endometrial preparation for the transfer of frozen-thawed embryos may influence maternal and fetal adaptation to pregnancy and could thus impact the results of the first trimester combined screening test. We conducted a retrospective cross-sectional study on singleton pregnancies achieved by embryo transfer of a single frozen-thawed blastocyst, comparing two different endometrial preparation protocols: natural cycle (n = 174) and hormone replacement therapy (HRT) (n = 122). The primary outcome was the risk of preeclampsia at the first trimester combined screening test. Secondary endpoints included variable reflecting fetal cardiac function (nuchal translucency and fetal heart rate), maternal adaptation (median arterial blood pressure—MAP and uterine arteries pulsatility index—UtA-PI), and placentation (pregnancy associated plasma protein A and placental growth factor). The risk of early preeclampsia was comparable in the two groups (38% vs. a 28%, p = 0.12). However, women in the natural cycle group showed lower fetal heart rate (159 [155–164] vs. 164 [158–168], p = 0.002) and higher UtA-PI (0.96 [0.74–1.18] vs. 0.72 [0.58–0.90], p &lt; 0.001). The frequency of a screening test at high risk for aneuploidies was similar. The modality of transfer of frozen-thawed embryos is associated with changes in the variables reflecting maternal and fetal cardiovascular function.

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.

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-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

Pregnancy Outcomes for Day 5 Versus Day 6 Single Frozen-thawed Blastocyst Transfer with Different Qualities of Embryos: A Large Matched-cohort Study.

This study aimed to determine whether the day of blastocyst expansion affects pregnancy outcomes in frozen-thawed blastocyst transfer (FBT) cycles. A retrospective match-cohort study was conducted. Patients who underwent blastocyst transfer in frozen-thawed cycles at day 5 or 6 were matched for potential confounding factors. A total of 2207 matched pairs of FBT cycles were included from January 2016 to December 2019 in our Reproductive Medicine Center. The clinical pregnancy rate (CPR) and live birth rate (LBR) were significantly increased in day 5 blastocyst transfers when compared to day 6 blastocyst transfers, in terms of the same embryo quality. For FBT cycles with good-quality embryo, the CPR at day 5 and 6 was 61.30% and 57.56%, respectively (P=0.045), and the LBR was 44.79% and 36.16%, respectively (P<0.001). For FBT cycles with poor-quality embryo, the CPR at day 5 and 6 was 48.61% and 40.89%, respectively (P=0.006), and the LBR was 31.71% and 25.74%, respectively (P=0.019). The CPR for FBT cycles with good-quality embryo was statistically higher at day 6 than that at day 5 with poor-quality embryo transferred (57.56% vs. 48.61%, P=0.001). Maternal age, anti-Müllerian hormone (AMH), endometrial thickness, embryo quality, and the day of blastocyst expansion were independently correlated with the CPR and LBR. The FBT cycles at day 5 had significantly higher CPR (adjusted odds ratio [OR]=1.246, 95% confidence intervals [CI]: 1.097-1.415, P=0.001) and LBR (adjusted OR=1.435, 95% CI: 1.258-1.637, P<0.001) than those at day 6. The embryo quality is the primary indicator for FBT cycles. Day 5 blastocysts should be preferred when the quality of embryo at day 5 is the same as that at day 6.

Trophectoderm biopsy is associated with adverse obstetric outcomes rather than neonatal outcomes

BackgroundWith the wide application of preimplantation genetic testing (PGT) with trophectoderm (TE) biopsy, the safety of PGT has always been a concern. Since TE subsequently forms the placenta, it is speculated that the removal of these cells was associated with adverse obstetrical or neonatal outcomes after single frozen-thawed blastocyst transfer (FBT). Previous studies report contradictory findings with respect to TE biopsy and obstetric and neonatal outcomes.MethodsWe conducted a retrospective cohort study including 720 patients with singleton pregnancies from single FBT cycles who delivered at the same university-affiliated hospital between January 2019 and March 2022. The cohorts were divided into two groups: the PGT group (blastocysts with TE biopsy, n = 223) and the control group (blastocysts without biopsy, n = 497). The PGT group was matched with the control group by propensity score matching (PSM) analysis at a ratio of 1:2. The enrolled sample sizes in the two groups were 215 and 385, respectively.ResultsPatient demographic characteristics were comparable between the groups after PSM except for the proportion of recurrent pregnancy loss, which was significantly higher in the PGT cohort (31.2 vs. 4.2%, P < 0.001). Patients in the PGT group had significantly higher rates of gestational hypertension (6.0 vs. 2.6%, adjusted odds ratio (aOR) 2.91, 95% confidence interval (CI) 1.18–7.18, P = 0.020) and abnormal umbilical cord (13.0 vs. 7.8%, aOR 1.94, 95% CI 1.08–3.48, P = 0.026). However, the occurrence of premature rupture of membranes (PROM) (12.1 vs. 19.7%, aOR 0.59, 95% CI 0.35–0.99, P = 0.047) was significantly lower in biopsied blastocysts than in unbiopsied embryos. There were no significant differences in regard to other obstetric and neonatal outcomes between the two groups.ConclusionsTrophectoderm biopsy is a safe approach, as the neonatal outcomes from biopsied and unbiopsied embryos were comparable. Furthermore, PGT is associated with higher risks of gestational hypertension and abnormal umbilical cord but may have a protective effect on PROM.

The effects of unexpected follicular growth and ovulation in artificial cycles: a retrospective cohort study of frozen, single-blastocyst transfer

To study the effects of unexpected follicular development and ovulation in artificial cycles (ACs) on pregnancy outcomes. A retrospective cohort study. A university-affiliated fertility center. A total of 1,427 patients who underwent a single, frozen-thawed blastocyst transfer with AC regimens from January 2014 to December 2020 at a university-affiliated fertility center were included. Unexpected follicular development and ovulation in ACs. Live birth rate (LBR), biochemical pregnancy rate, clinical pregnancy rate, and ongoing pregnancy rate. A total of 161 patients with unexpected follicular development and ovulation in ACs (ovulation group) and 1,266 patients without growing follicles in ACs (control group) were enrolled. The patients in the ovulation group were older and had higher levels of serum follicle-stimulating hormone and lower levels of serum antimüllerian hormone. After propensity score matching, the baseline characteristics between the 2 groups were comparable and no significant difference was observed in the LBR (ovulation group, 39.0% vs. control group, 39.0%), biochemical pregnancy rate (ovulation group, 60.3% vs. control group, 58.2%), clinical pregnancy rate (ovulation group, 53.4% vs. control group, 50.7%), or ongoing pregnancy rate (ovulation group, 42.5% vs. control group, 40.4%). Moreover, the patients in the ovulation group showed a lower risk of hypertensive disorders of pregnancy (HDP) (1.6% vs. 15.3%). A subgroup analysis of women who delivered singleton live-born babies also demonstrated that unexpected follicular development and ovulation in ACs was associated with a decreased risk of HDP (adjusted odds ratio, 0.070; 95% confidence interval, 0.007-0.712) and an increased risk of large-for-gestational-age infants (adjusted odds ratio, 4.046; 95% confidence interval, 1.319-12.414). Women with unexpected follicular development and ovulation during single frozen-thawed blastocyst transfer with AC regimens had a similar LBR and a reduced risk of HDP compared with those with routine AC regimens, and singleton neonates had an increased risk of being large for gestational age.

Live birth rate following frozen-thawed blastocyst transfer is higher in high-grade day 6 blastocysts than in low-grade day 5 blastocysts.

Day 5 (D5) blastocysts are generally given priority to transfer than day 6 (D6) blastocysts; however, which one should be prioritized to transfer when only low-grade D5 and high-grade D6 blastocysts are available? A large retrospective cohort study was carried out to evaluate the live birth rate (LBR) following D5 and D6 blastocysts in single frozen-thawed blastocyst transfer (FBT) during January 2014 and December 2018.A multivariate logistic regression was conducted to evaluate the combined impact of expansion day (D5 and D6) and blastocyst quality (high grade/low grade) on LBR, accounting for the potential confounding factors. The biopsied blastocysts from a consecutive PGT-A case series during February 2013 to December 2021 were analyzed in a supplementary study. The LBR achieved in high-grade D6 blastocyst transfer was significantly higher than that in low-grade D5 blastocyst transfer (50.43% vs. 40.70%, aOR 1.54, 95% CI 1.05-2.26, p = 0.027). There were no significant differences in preterm birth rate, very preterm birth rate, mean live birth weight, and birth weight <1,500 g and >4,000 g between the two cohorts. As for aneuploidy analysis in PGT, there were 54.55% of euploid blastocysts (30/55) among high-grade D6 blastocysts, significantly higher than the 41.39% of euploid blastocysts (565/1,365) among low-grade D5 blastocysts (p < 0.001). Our data suggest that D6 blastocysts with high morphology grading are preferred than D5 blastocysts with low morphology grading when selecting blastocyst transfer to shorten the time of conception.

O-148 Does trophectoderm biopsy affect the initial level and rate of increase in serum ß-HCG levels? A comparison of preimplantation genetic testing (PGT) and non-PGT cycles

Abstract Study question Does trophectoderm biopsy affect the initial level and rate of increase in ß-HCG levels after single frozen-thawed blastocyst transfer?A comparison of PGT and non-PGT cycles. Summary answer Initial serum β-hCG concentrations from cycles resulting in a live birth was significantly lower than that for the non-PGT group. What is known already β-hCG may serve as early predictor of pregnancy outcome and potentially assist in reducing stress related to the uncertainty of outcome in assisted reproductive technologies (ART) treatments and counselling. hCG is produced primarily by differentiated syncytiotrophoblasts. Due to removal of trophectoderm cells, the secretion of β-hCG may be affected. Little, however, is known about the influence of trophectoderm biopsy on serum β-hCG levels in early pregnancy. Therefore, it is important to investigate if the levels and pregnancy outcomes predictive values of β-hCG vary in PGT and non-PGT cycles. Study design, size, duration This was a single center retrospective cohort study conducted at Assisted Reproductive Technologies and Reproductive Genetics Center, Istanbul Memorial Hospital, Istanbul, Turkey between January 2012-January 2021. A cohort of women with frozen-thawed single blastocysts transfers and having positive serum ß-HCG results on day 9 following ET (≥20 IU/L) were allocated into two groups; PGT group (1777 cycles) and non-PGT group (1874 cycles). Participants/materials, setting, methods The serum ß-hCG levels on day 9 and 11 after embryo transfer (ET) and the rate of ß-hCG increase were compared between the PGT and non-PGT cycles with respect to biochemical pregnancy loss (BPL), clinical pregnancy loss (CPL), and live birth. The cutoff values of initial β-hCG levels and the rate of ß-hCG increase from day- 9 to day-11 were evaluated for live birth and compared between the two groups. Main results and the role of chance Initial β-hCG levels were significantly higher in pregnancies resulting in live birth (184.68±99.54 IU/L, p = &amp;lt;0.001) compared to BPL (66.65±55.29 IU/L) and CLP (140.51±88.98 IU/L) in the PGT group. Moreover, initial β-hCG levels were significantly higher in pregnancies resulting in live birth (192.53±97.93 IU/L, p = &amp;lt;0.001) compared to BPL (73.67±58.07 IU/L) and CLP (156.28±98.29 IU/L) in the non-PGT group. In addition, initial serum β-hCG concentrations from cycles resulting in a live birth was 184.68±99.54 IU/L for the PGT group, which was significantly lower than that for the non-PGT group (192.53±97.93 IU/L, p = 0.004). The diagnostic threshold of initial β-hCG levels predicting a live birth was 122.5 IU/L (sensitivity 70.1 %, specificity 60.1 %, PPV 84.7 %, and NPV 38.9 %) and 130.5 IU/L (sensitivity 71.7 %, specificity 61.6 %, PPV 82.2 %, and NPV 46.9 %) in the PGT and non-PGT groups, respectively. The rate of increase of serum β-hCG threshold predicting a live birth for the PGT group was 2.33 (sensitivity 73.8 %, specificity 59.9 %, PPV 85.3 %, and NPV 42 %) and 2.42 (sensitivity 64.6 %, specificity 60.1 %, PPV 80 % and NPV 40.7 %) for the non-PGT group. Limitations, reasons for caution This is a retrospective analysis. Wider implications of the findings Initial serum β-hCG values and the rate of β-hCG increase may be useful for predicting pregnancy outcomes in PGT cases undergoing trophectoderm biopsy. Trial registration number Not applicable

P-763 effect of duration of cryo-storage of vitrified embryos on obstetric and perinatal outcomes

Abstract Study question Does the duration of cryo-storage of vitrified embryos affect obstetric and perinatal outcomes? Summary answer Duration of cryo-storage with an open vitrification system did not affect obstetric and perinatal outcomes. What is known already Frozen-thawed blastocyst transfer has been performed widely with improvement of embryo culture conditions and cryopreservation techniques. Although blastocyst vitrification has become an essential method to improve clinical outcomes of IVF, there has been little study into the relationship between a long duration of cryo-storage in liquid nitrogen and obstetric and perinatal outcomes. Study design, size, duration This retrospective study was conducted at Kyono ART Clinic from January 2007 to December 2020. This study includes a total of 1053 singletons derived from 2461 frozen-thawed blastocyst transfers in 2461 patients. Steel’s multiple comparison test was performed for clinical and perinatal outcomes with cases of cryo-storage of less than 3 months as a control group. P &amp;lt; 0.05 was considered statistically significant. Participants/materials, setting, methods The subjects are patients who underwent their first single frozen-thawed blastocyst transfer (FBT) with an open vitrification system. Females &amp;gt;40 years old at cryopreservation and those who underwent preimplantation genetic testing were excluded. According to cryo-storage duration, patients were grouped as follows: group A, 0-3 months (1255 cycles); group B, 3-6 months (1008 cycles); group C, 6-12 months (162 cycles), group D, 12-24 months (36 cycles). Main results and the role of chance Both the mean maternal age at blastocyst cryopreservation (A: 33.7±3.6, B: 34.1±3.5, C: 34.8±3.2, D: 35.1±3.3) and the mean maternal age at FBT (A: 33.8±3.6, B: 34.4±3.5, C: 35.5±3.1, D: 36.4±3.3) in groups B, C, and D were significantly higher compared to those in group A.. There was no significant difference in the survival rate after blastocyst thawing [A: 97.4% (1256/1290), B: 98.3% (1010/1027), C: 99.4% (163/164), D: 97.2% (35/36)]. The pregnancy rate in group C was significantly lower compared to group A [A: 60.0% (752/1254), B: 61.4% (619/1008), C: 48.1% (78/162), D: 63.9% (23/36)] The gestational age of group C was significantly lower compared to group A (A: 39.5±1.8, B: 39.4±1.8, C: 38.4±3.1, D: 39.8±1.6), but there were no significant differences in live birth weight or height. There were no significant differences in congenital abnormality rate [A: 1.3% (7/541), B: 2.5% (11/440), C: 1.8% (1/56), D: 0.0% (0/16)], placental abnormalities such as placenta previa [A: 1.3% (7/541), B: 1.6% (7/440), C: 1.8% (1/56), D: 0.0% (0/16)], perinatal abnormalities such as hypertensive disorders of pregnancy or gestational diabetes [A: 6.1% (33/541), B: 8.6% (38/440), C: 1.8% (1/56), D: 6.3% (1/16)] among the four groups. Limitations, reasons for caution We could not provide sufficient information on confounding factors such as smoking habits, and the sample size was too small for multivariate analysis. The safety of longer storage will need to be verified as this has not been clarified in this study. Wider implications of the findings The pregnancy rate in group C was significantly lower than that in group A, but the effect was small: 0.065, power of 0.78. Our data suggested that the duration of cryopreservation with an open vitrification system in liquid nitrogen did not affect obstetric or perinatal outcomes. Trial registration number not applicable

Down-Regulation Ovulation-Induction Leads to Favorable Outcomes in a Single Frozen-Thawed Blastocyst Transfer RCT.

ObjectiveElective single embryo transfer (eSET) has been increasingly advocated to achieve the goal of delivering a single healthy baby. A novel endometrial preparation approach down-regulation ovulation-induction (DROI) proposed by our team was demonstrated in an RCT that DROI could significantly improve the reproductive outcome compared with modified natural cycle. We aimed to evaluate whether DROI improved clinic pregnancy rate in this single frozen-thawed blastocyst transfer RCT compared with hormone replace treatment (HRT).MethodEligible participants were recruited and randomized into one of two endometrial preparation regimens: DROI or HRT between March 15, 2019 and March 12, 2021. The primary outcome was clinical pregnancy rate (CPR). The secondary endpoints included ongoing pregnancy rate (OPR), biochemical miscarriage and first trimester pregnancy loss. This trial is registered at the Chinese Clinical Trial Registry, number ChiCTR2000039804.Result (s)A total of 330 women were randomized in a 1:1 ratio between two groups and 289 women received embryo transfer and completed the study (142 DROI; 147HRT). Pregnancy outcomes were significantly different between the two groups. The CPR and OPR in the DROI group were significantly higher than those of the HRT group (64.08% versus 46.94%, P<0.01; 56.34% versus 38.78%,P<0.01). The biochemical miscarriage and first trimester pregnancy loss were comparable between the two groups.Conclusion (s)The findings of this RCT support the suggestion that the DROI might be a more efficient and promising alternative endometrial preparation approach for FET. Moreover, DROI could play a critical role in promoting uptake of single embryo transfer strategies in FET.

Perinatal outcomes of singleton live births after preimplantation genetic testing during single frozen-thawed blastocyst transfer cycles: a propensity score-matched study

To determine whether singleton pregnancy achieved after preimplantation genetic testing (PGT) is associated with a higher risk of adverse perinatal outcomes than invitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) singleton pregnancy. A retrospective cohort study. A university-affiliated fertility center. This cohort study included singleton live births resulting from PGT (n = 232) and IVF/ICSI singleton pregnancies (n=2,829) with single frozen-thawed blastocyst transfer. Multiple baseline covariates were used for propensity score matching, yielding 214 PGT singleton pregnancies matched to 617 IVF/ICSI singleton pregnancies. Trophectoderm biopsy. The primary outcome was gestational hypertension, and various clinical perinatal secondary outcomes related to maternal and neonatal health were measured. Compared with IVF/ICSI singleton pregnancy, PGT singleton pregnancy was associated with a significantly higher risk of gestational hypertension (adjusted odds ratio, 2.58; 95% confidence interval, 1.32, 5.05). In the matched sample, the risk of gestational hypertension remained higher with PGT singleton pregnancy (odds ratio, 2.33; 95% confidence interval, 1.04, 5.22) than with IVF/ICSI singleton pregnancy. No statistical differences were noted in any other measured outcomes between the groups. The perinatal outcomes of PGT and IVF/ICSI singleton pregnancies were similar except for the observed potentially higher risk of gestational hypertension with PGT singleton pregnancy. However, because the data on PGT singleton pregnancies are limited, this conclusion warrants further investigation.

Perinatal Outcomes of Singleton Live Births Following Preimplantation Genetic Testing for Chromosomal Structural Rearrangements in Single Frozen-Thawed Blastocyst Transfer Cycles: a Retrospective Cohort Study.

This study investigated whether singleton pregnancies conceived after preimplantation genetic testing for chromosomal structural rearrangements (PGT-SR) are associated with a higher risk of adverse perinatal outcomes than singleton pregnancies conceived after intracytoplasmic sperm injection (ICSI). We collected data on singleton live births after PGT-SR (n = 107) and ICSI (n = 585) in our hospital from January 2017 to August 2020. Multivariable analyses were used to adjust for maternal age, body mass index, gravidity and parity, paternal age, ovulatory disorder, and recurrent spontaneous abortion. The unadjusted results showed a significantly higher risk of hypertensive disorders of pregnancy (HDP) (odds ratio (OR) = 2.47; 95% confidence interval (CI): 1.10-5.54; P = 0.029) associated with PGT-SR singleton pregnancies than with ICSI singleton pregnancies. However, after adjusting for potential confounders, there were no longer any significant differences in the risk of HDP (adjusted OR = 2.24; 95% CI: 0.92-5.48; P = 0.077) between PGT-SR and ICSI singleton pregnancies. There were no significant differences between PGT-SR and ICSI singleton pregnancies in terms of gestational diabetes, preterm premature rupture of membranes, placenta previa, cesarean delivery, gestational age (weeks), preterm delivery (< 37weeks), very preterm delivery (≥ 28weeks and< 32weeks), birth weight (g), low birth weight (< 2500g), very low birth weight (< 1500g), birth height (cm), birth defects, and 1-min and 5-min Apgar scores. In conclusion, for single frozen-thawed blastocyst cycles, there were no significant differences in adverse perinatal outcomes between PGT-SR and ICSI singleton pregnancies. However, due to the limited sample size, these conclusions need to be confirmed by further studies.