Preimplantation Genetic Testing For Aneuploidy Cycles Research Articles

The kinetics of nucleolar precursor bodies clustering at the pronuclei interface: Positive correlations with the morphokinetic characteristics of cleaving embryos and euploidy in preimplantation genetic testing programs

Objective: This study investigated potential relationships between the kinetics of nucleolar precursor bodies (NPBs) in the pronucleus and developmental morphokinetics and euploidy in human preimplantation genetic testing for aneuploidy (PGT-A) cycles.Methods: The morphokinetic analysis of 200 blastocysts obtained from 53 PGT-A cycles was performed retrospectively in a time-lapse incubator. At the time of pronuclear breakdown (PNBD), we categorized the blastocysts into two groups based on the kinetic degree of clustering NPBs at the interface of the two pronuclei: clustered NPBs (CL) and non-clustered NPBs (NCL). We then compared morphokinetic parameters, abnormal behavioral events, and the rate of aneuploidy between the two groups.Results: Pronuclear fading and the first cleavage occurred earlier in the NCL group than in the CL group. However, the initiation of blastocyst formation and blastocyst expansion was delayed in the NCL group relative to the CL group. No differences were found in the rate of abnormal cleavage events, such as multinucleation at the 2-cell stage, direct cleavage from one to three cells, and from two to five cells between the CL and NCL groups. However, the fragmentation rate at the 8-cell stage was higher in the NCL group than in the CL group (10.3% vs. 1.9%, p<0.05). Additionally, the euploid rate in the CL group was significantly higher than in the NCL group (37.9% vs. 12.4%, p<0.05).Conclusion: These results demonstrate the effectiveness of combining NPB clustering at PNBD with morphokinetics as a parameter for selecting embryos with higher developmental potential in in vitro fertilization.

Do sperm factors influence embryonic aneuploidy? Long live the oocyte.

What is the impact of male age- and sperm-related factors on embryonic aneuploidy? Using a 3-fold analysis framework encompassing patient-level, embryo-level, and matching analysis, we found no clinically significant interactions between male age and sperm quality with embryo ploidy. While the effect of maternal age on embryo chromosomal aneuploidy is well-established, the impact of male age and sperm quality on ploidy is less well-defined. This retrospective cohort study analyzed autologous preimplantation genetic testing for aneuploidy (PGT-A) and frozen embryo transfer cycles from December 2014 to June 2021. The study involved 11087 cycles from 8484 patients, with a total of 35797 embryos. The aneuploidy rate, calculated as the ratio of aneuploid blastocysts to the total number of blastocysts biopsied in a single treatment cycle, was evaluated. In the embryo-level analysis, the main outcome measure was the ploidy state of the embryos. The study employed a multifaceted analytical approach that included a patient-level analysis using generalized linear mixed models, an embryo-level analysis focusing on chromosomal ploidy, and a propensity score matching analysis contrasting groups with distinct ploidy rates (0% and 100%). There were no interventions as this was an observational study of PGT-A cycles. No clinically relevant factors influencing ploidy rate related to male and sperm quality were revealed. In contrast, female age (coefficient = -0.053), BMI (coefficient = 0.003), prior ART cycle (coefficient = -0.066), and number of oocytes retrieved (coefficient = -0.018) were identified at the patient level. Embryo analysis identified age (coefficient = -0.1244) and ICSI usage (coefficient = -0.0129) as significant factors. Despite these, no significant interactions between male and female assessed factors on the ploidy rate emerged. Propensity score matching between maximal (100% vs 0%) euploid rates did not reveal significant differences of influence by male age and sperm quality. The focus on patients having blastocyst biopsy for PGT-A may not reflect the broader IVF population. Other semen quality parameters like DNA fragmentation were not included. Exclusion of embryo mosaicism from the analysis could affect aneuploidy rate interpretations. There may also be unmeasured influences like lifestyle or environmental factors. Male age and sperm quality parameters were consistent across both maximal and minimal ploidy rate comparisons. No significant clinical characteristics related to the factors assessed for the male-influenced blastocyst ploidy status, confirming the dominancy of the oocyte and female age. The study was not funded. There are no competing interests. N/A.

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

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

Factors affecting biochemical pregnancy loss (BPL) in preimplantation genetic testing for aneuploidy (PGT-A) cycles: machine learning-assisted identification

PurposeTo determine the factors influencing the likelihood of biochemical pregnancy loss (BPL) after transfer of a euploid embryo from preimplantation genetic testing for aneuploidy (PGT-A) cycles.MethodsThe study employed an observational, retrospective cohort design, encompassing 6020 embryos from 2879 PGT-A cycles conducted between February 2013 and September 2021. Trophectoderm biopsies in day 5 (D5) or day 6 (D6) blastocysts were analyzed by next generation sequencing (NGS). Only single embryo transfers (SET) were considered, totaling 1161 transfers. Of these, 49.9% resulted in positive pregnancy tests, with 18.3% experiencing BPL. To establish a predictive model for BPL, both classical statistical methods and five different supervised classification machine learning algorithms were used. A total of forty-seven factors were incorporated as predictor variables in the machine learning models.ResultsThroughout the optimization process for each model, various performance metrics were computed. Random Forest model emerged as the best model, boasting the highest area under the ROC curve (AUC) value of 0.913, alongside an accuracy of 0.830, positive predictive value of 0.857, and negative predictive value of 0.807. For the selected model, SHAP (SHapley Additive exPlanations) values were determined for each of the variables to establish which had the best predictive ability. Notably, variables pertaining to embryo biopsy demonstrated the greatest predictive capacity, followed by factors associated with ovarian stimulation (COS), maternal age, and paternal age.ConclusionsThe Random Forest model had a higher predictive power for identifying BPL occurrences in PGT-A cycles. Specifically, variables associated with the embryo biopsy procedure (biopsy day, number of biopsied embryos, and number of biopsied cells) and ovarian stimulation (number of oocytes retrieved and duration of stimulation), exhibited the strongest predictive power.

P-231 How many blastocysts are necessary to reach pregnancy with preimplantation genetic testing?

Abstract Study question What is the influence of the number of blastocysts before biopsy on the prognosis of pregnancy in preimplantation genetic testing for aneuploidy (PGT-A) cycles? Summary answer The number of pre-biopsy blastocysts seems to be a parameter that can be used as a prognostic factor for the pregnancy chance in PGT-A cycles. What is known already Advances in embryo cryopreservation techniques have allowed for a greater use of PGT. Studies showed that PGT-A has improved live birth rates while reducing the number of embryos transferred. There is a lot of information about the role of the oocyte number as a predicting factor for pregnancy rate. However, little information is available about the influence of the number of blastocysts before performing PGT-A on the chance of achieving a pregnancy. Study design, size, duration Retrospective study performed in a reproductive medicine center using the first IVF cycle from 2016 to 2023, including 682 patients with at least one blastocyst before undergoing PGT-A. All patients performed a single embryo transfer in each procedure, in up to 4 transfers. Participants/materials, setting, methods The sample was divided into four groups according to the blastocyst number: G1, 1 to 2 blastocysts (n = 324); G2, 3 to 4 (n = 197); G3, 5 to 9 (n = 137); and G4, ≥ 10 blastocysts (n = 24); each group was divided according to female age (≤ 37 and &amp;gt; 37) Variables: female age, and euploidy, clinical pregnancy per transfer and cumulative clinical pregnancy rates. Data were compared between groups. Statistical analysis: Chi-square test (Bonferroni correction) and Anova (p &amp;lt; 0.05). Main results and the role of chance The results in G1, G2, G3 and G4 were, respectively: female age, yo (40 vs. 38.4 vs. 37.2 vs. 34.7, p &amp;lt; 0.01); euploidy rate (34.6 vs. 67.2 vs. 83.2 vs. 100.0, p &amp;lt; 0.0001), clinical pregnancy rate per transfer, % (45.5 vs. 58.6 vs. 72.8 vs. 95.8 p &amp;lt; 0.0001 ), cumulative clinical pregnancy rate, % (15,7 vs. 39.4 vs. 60.6 vs. 95,8% p &amp;lt; 0.0001). Women with 1 to 2 blastocysts before biopsy had a cumulative pregnancy rate more than 3-fold lower than those with 3 to 4 blastocysts (%, 39.6 vs. 15.3, p &amp;lt; 0.001, OR 3.59, CI 95% 2.32 to 5.57) and more than 8-fold lower than those with 5 to 9 blastocysts (%, 60,6 vs. 15.3, p &amp;lt; 0.001, OR 8.42, CI 95%: 5.20 to 13.64). The comparison in each group according to female age showed that until 9 blastocysts, the younger women had a pregnancy rate higher than the older, respectively (%): G1: 30.8 vs. 12.5, p = 0.001; OR 3.1, CI 95%: 1.44 to 6.48; G2: 57.4 vs. 30.2, p &amp;lt; 0.001; OR 3.10, CI 95%: 1.61 to 5.98; G3: 72.6 vs. 50.7, p = 0.009. OR 2.58; IC 95%: 1.19 to 5.67; and G4: 93.8 vs. 87.5, p = 0.268. Limitations, reasons for caution As a retrospective study, data collection and filling limitations should be considered. Wider implications of the findings The number of pre-biopsy blastocysts appears to be a parameter that can be used as a prognostic factor for the pregnancy chance in PGT-A cycles. Even transferring 1 embryo, the pregnancy rate/transfer was higher with more blastocysts. In patients with less than 10 blastocysts before PGT, age influences pregnancy rates. Trial registration number Not Applicable

P-529 Optical Genomic Mapping (OGM) enable cryptic chromosomal rearrangements in a couple with recurrent miscarriages undergoing preimplantation genetic diagnosis

Abstract Study question Could Optical Genomic Mapping (OGM) detect chromosomal structural variations (SVs) below the detection limit of conventional cytogenetic diagnostics in couples with recurrent miscarriages? Summary answer The Next-generation cytogenetics of Optical Genomic Mapping confirmed a cryptic chromosomal translocation in a couple with recurrent miscarriages undergoing preimplantation genetic testing for aneuploidies (PGT-A). What is known already Chromosomal structural variants (SVs) significantly contribute to infertility, recurrent pregnancy losses and congenital defects... Approximately 2-4% of couples facing recurrent miscarriages carry chromosomal abnormalities. Currently, their detection is based on convencional cytogenetic methods (karyotyping, FISH or array-CGH), however cryptic chromosomal rearrangements are difficult to identify. Next-generation cytogenetics such as OGM is able to detect SVs with a resolution of &amp;lt; 500 kb, allowing a better understanding of the cause of patient’s infertility. In our study, we utilized OGM to confirm a cryptic translocation in a couple experiencing recurrent miscarriages, aiming to enhance our understanding of the underlying causes of their infertility. Study design, size, duration Our study focuses on a non-consanguineous couple diagnosed with recurrent pregnancy loss that attended to our private fertility clinic to undergo assisted reproductive treatment (ART) with their autologous semen, oocytes and PGT-A. Conventional cytogenetic technique was performed on both partners by G-banding karyotyping. PGT-A was performed by NGS (Veriseq, Illumina). Optical Genomic Mapping (OGM) served as a diagnostic tool, complemented by lymphocyte FISH analysis to confirm chromosomal structural variations in these infertile patients. Participants/materials, setting, methods Ultra High Molecular Weight genomic DNA (UHMW gDNA) was extracted from frozen human peripheral blood of both partners. UHMW gDNA was quantified using Qubit dsDNA assay BR kit and Qubit 4 Fluorometer (Thermo Fisher Scientific). We used Saphyr system (Bionano Genomics) for cytogenetic diagnosis. The consensus genomic map was constructed by de novo assembly in the Bionano Solve data analysis software. SVs were identified by aligning Optical Genomic Map with the reference genome GRCh38/hg38. Main results and the role of chance The couple had suffered four prior miscarriages and undergoing three PGT-A cycles. Both partners provided a normal karyotype. Among 13 biopsied embryos, four showed CNVs on chromosomes 2(p24.3è25.3, 12Mb) and 6(p24.1è25.3, 11Mb). Following this result we suspected that the couple might has a cryptic chromosomal structural abnormalities. To test our hypothesis, we performed OGM. We analysed UHMW gDNA samples from both partners. OGM generated an average of 823.67Gb. The average N50 molecule length (≥150kb) was 318kb. The average mapping rate was 90.75% and the average labeling rate was 15.30 labels per 100kb. The average effective coverage depth was 242X. OGM successfully identified a cryptic translocation in the male partner ogm[GRch38]t(2;6)(p24.3;24.1), while the female partner showed no abnormalities. Translocation breakpoints identified by OGM were Chr2:12.560.508 and Chr6:11.622.593. The translocated segments were near to the detection limit of conventional cytogenetic analysis and with similar pattern that could be the reason for missed detection by karyotyping. Importantly, we identified one gene disrupted by OGM rearrangement breakpoint: MIR3681HG. A previous study considered that CNV loci of 2p24.3, including MIR3681HG gene, could be associated with spermatogenesis. The lymphocyte FISH analysis finding corroborated the OGM result. Limitations, reasons for caution OGM is a very powerful method for detecting chromosomal structural variants in human genomes and is able to detect cryptic structural variants. However, this is a very new diagnostic application, so there is limited experience with OGM for correlating structural variations results to infertility diagnosis in couples with recurrent miscarriages. Wider implications of the findings A balanced cryptic translocation has been identified in a couple with recurrent miscarriages. Our case report demonstrates the high diagnostic capability of Optical Genomic Mapping for cryptic SVs. OGM technology allows a more accurate cytogenetic diagnosis by detecting cryptic structural variants with high resolution in infertile patients with recurrent miscarriages. Trial registration number not applicable

P-612 Euploidy rates between cycles triggered with gonadotrophin-releasing hormone agonist (GnRHa), human chorionic gonadotrophin (hCG) and dual trigger

Abstract Study question Is there any difference in euploidy rates between in vitro fertilization (IVF) cycles triggered with GnRHa, hCG or dual trigger? Summary answer There is no difference in the euploidy rate in preimplantation genetic testing for aneuploidy (PGT-A) cycles according to the trigger method used. What is known already The use of PGT-A has shown that the success of meiosis in the IVF laboratory is inversely correlated with maternal age. However, other uninvestigated factors involved in the IVF process may interfere with normal oocyte physiology. Since the final maturation obtained after ovarian stimulation depends on the use of drugs to promote the resumption of meiosis, it is worth investigating whether the triggering method could impact on oocyte and embryo euploidy. This study aims is to evaluate differences in embryo euploidy rates between PGT-A cycles triggered with GnRHa, hCG or dual trigger (GnRHa + hCG). Study design, size, duration This is a single-center retrospective study of 934 patients who underwent 1085 PGT-A cycles by Next-Generation Sequencing (NGS) from January 2017 to December 2023, using one of three possible trigger methods to induce final oocyte maturation: GnRHa, hCG, or dual trigger. The couples included in the study had normal karyotypes and no severe male factor. Participants/materials, setting, methods Data on the number of oocytes retrieved, ratio of metaphase II (MII) oocytes and fertilization rate, blastocyst development and embryo euploidy were assessed and compared between the GnRHa, hCG and dual trigger treatments. A secondary analysis was performed to evaluate data stratified by patient age. Main results and the role of chance A total of 1085 PGT-A cycles involving 934 patients (38.07 ± 3.01 years) and 2803 biopsied blastocysts were included in the analysis. Dual trigger was used in 726 (77.73%) cycles, GnRHa in 287 (26,4%) cycles and hCG in 72 (7.71%) cycles. The number of oocytes retrieved was significantly higher in the GnRHa group (GnRHa: 18.72 ± 8.59; hCG: 9.88 ± 5.64; dual trigger: 10.58 ± 5.65; p &amp;lt; 0.001) with similar maturation rate (GnRHa: 77.46%; hCG: 74.58%; dual trigger: 76.03%; p = 0.789), fertilization rate (GnRHa: 78.12%; hCG: 76.37%; dual trigger: 79.12%; p = 0.168), blastulation rate (GnRHa: 61.03%; hCG: 58.32%; dual trigger: 58.73%; p = 0,629), high-quality blastocyst rate (GnRHa: 27,88%; hCG: 33,67%; dual trigger: 27,88%; p = 0.543) and embryo euploidy per biopsied embryo (GnRHa: 42.48%; hCG:45.49%; dual trigger:46.98%; p = 0.112). Analysis of the data stratified by age showed similar rates of euploidy rates with the three trigger methods in women younger than 41 years (&amp;lt;35 years: GnRHa 66.50%; hCG 66.67%; dual trigger 56.97% p = 0.290; 35-37 years: GnRHa 49.45% hCG 51.04%; dual trigger 50.23%; p = 0.988; 38-40 years: GnRHa 40.93%; hCG 41.27%; dual trigger 39.13% p = 0.257). However, in patients ≥41 years old the euploidy rate was statistically higher in the GnRHa group (GnRH 31.51%; hCG 18.75%; dual trigger 16.89%; p = 0.032). Limitations, reasons for caution The main limitations of the study are: its retrospective design, the possibility that the trigger method was chosen based on the ovarian response and the limited number of patients in both the hCG trigger and women ≥ 41 years groups. Wider implications of the findings Our results suggest that triggering with GnRHa, hCG or dual trigger leads to comparable euploidy rates. Triggering with GnRHa should be recommended in older patients since it has been associated with a higher rate of embryonic euploidy. Trial registration number Not Applicable

P-539 Chaotic blastocysts in preimplantation genetic testing for aneuploidies: prevalence, characterization and re-biopsy results

Abstract Study question Are we excluding blastocysts with favorable reproductive potential when embryos are designated as chaotic by Preimplantation Genetic Testing for Aneuploidies (PGT-A)? Summary answer The re-biopsy of chaotic blastocysts can rescue embryos with favorable reproductive potential only when there are ≥5 chromosomes displaying intermediate copy number values (CNV). What is known already An embryo is deemed as chaotic when multiple aneuploidies (5, 6 or more) are detected in the biopsied cells of the trophectoderm. Such embryos are classified as aneuploid, therefore their transfer is not recommended. There is evidence that chaotic embryos may result from the biopsy of apoptotic cells, cellular fragments and, more broadly, DNA degraded by multiple factors. Studies involving the re-biopsy and re-testing of a limited number of chaotic embryos have found a relevant percentage of euploid results. Moreover, there has been published a case report of a healthy live birth after the transfer of a chaotic embryo. Study design, size, duration This is a retrospective study of 1,442 cycles of PGT-A performed in twenty-two in vitro fertilization (IVF) clinics from November 2017 to December 2023. A total of 5,801 blastocysts were biopsied and analyzed in a single reference laboratory using Next-Generation Sequencing. Ninety-three chaotic blastocysts donated from patients who provided informed consent were thawed for re-biopsy in two IVF clinics. The subsequent re-analysis was performed in the same PGT laboratory using the same methodology. Participants/materials, setting, methods This study assessed the prevalence of chaotic embryos in all included cycles. Chaotic embryos were considered those with ≥5 chromosomes showing CNV below 1.75 or above 2.25. We sub-classified these embryos into pure chaotic (≥5 uniform aneuploidies), mixed chaotic (≥5 alterations considering uniform aneuploidies and chromosomes with intermediate CNV) and mosaic chaotic (≥5 chromosomes with intermediate CNV). Re-biopsies of 69 chaotic blastocysts were compared to the initial PGT-A results. Main results and the role of chance The prevalence of chaotic embryos was 4.3% (251/5,801); 13.5% (n = 34) pure, 53.0% (n = 133) mixed and 33.5% (n = 84) mosaic. After thawing 93 embryos, the survival rate was 74.2%. The 69 embryos that survived underwent re-biopsy yielding the following PGT-A results: 24.6% (n = 17) euploid, 37.7% (n = 26) chaotic, 26.1% (n = 18) aneuploid non-chaotic, 7.2% (n = 5) mosaic and 4.4% (n = 3) non informative. Nevertheless, outcomes varied substantially when the analysis was conducted based on the sub-category of chaotic embryos. In the pure category (n = 11), 72.7% (n = 8) showed identical results to the initial biopsy while 27.3% (n = 3) were aneuploid non-chaotic confirming at least one aneuploidy identified at the initial biopsy. Among the mixed category (n = 24), 54.2% (n = 13) were also mixed chaotic, and 45.8% (n = 11) were aneuploidy non-chaotic. All re-biopsies in this category also manifested at least one common aneuploidy with the initial biopsy or its opposite (trisomy/monosomy). In the mosaic category (n = 31), 54.8% (n = 17) were euploid, 16.1% (n = 5) were mosaic chaotic, 16.1% (n = 5) were mosaic non-chaotic and 12.9% (n = 4) were aneuploid non-chaotic. The concordance with the initial biopsy in terms of aneuploid result was 100% in the pure and mixed chaotic categories. However, over half of the embryos initially categorized as mosaic chaotic were, in fact, euploid. Limitations, reasons for caution Implantation, miscarriage and live birth rates are not explored. These outcomes are crucial for understanding the clinical significance of euploid embryos initially deemed as chaotic. The survival rate of chaotic embryos should be considered as it is lower than the survival rate of vitrified blastocysts reported in most IVF laboratories. Wider implications of the findings Previous research has suggested that re-biopsy can rescue embryos from PGT-A cycles given that a chaotic result has reduced predictive value. However, our current study reveals that not all chaotic embryos are suitable for re-biopsy, as 100% of pure and mixed chaotic blastocysts were aneuploid when re-tested. Trial registration number Not applicable

P-547 Impact of SARS-COV-2 infection on embryo euploidy rate: a retrospective cohort study of 498 PGT-A cycles in China

Abstract Study question Does SARS-CoV-2 infection before oocyte retrieval have any impacts on embryo euploidy rate? Summary answer SARS-CoV-2 infection before oocyte retrieval had no detrimental impact on embryo euploidy rate, indicating that cycle cancellation due to SARS-CoV-2 infection may not be necessary. What is known already SARS-CoV-2 infection has significant effects on the health of people worldwide and poses a serious threat to reproductive health. According to the previous studies, SARS-CoV-2 infection had negative impacts on the blastocyst formation rate, top-quality embryos rate. However, the association between the infection and the embryo euploidy rate is indeterminate. It is still worth exploring the impact of SARS-CoV-2 infection on embryo euploidy rate. Especially this is the key question to be addressed for providing appropriate counseling to couples seeking for preimplantation genetic testing for aneuploidy (PGT-A) treatments during the ongoing pandemic. Study design, size, duration This was a retrospective cohort study of 498 couples who underwent PGT-A cycles with next-generation sequencing technology from November 1st, 2022 to June 30th, 2023 at a tertiary-care medical center in China. Participants/materials, setting, methods Women tested positive for SARS-CoV-2 before oocyte retrieval were included in the COVID-19 group, while patients who were asymptomatic and tested negative during the same period were included in the non-COVID-19 group. The primary outcome was the euploidy rate. Subgroup analysis was conducted according to the time interval between infection and oocyte retrieval. Univariate and multivariate logistic regression models were applied to adjust for potential confounders. Main results and the role of chance A total of 278 and 220 women were included in the COVID-19 and non-COVID-19 group, respectively. In the COVID-19 group, the maturated oocyte rate (79.5% vs. 83.7%, p＜0.001), number of total viable embryos (2 vs. 3, p=0.038), and number of euploid blastocyst (1 vs. 1, p=0.028) were significantly decreased compared with non-COVID-19 group. The euploidy rate (38.5% vs.40.3%, p = 0.451), aneuploidy rate (45.0% vs. 43.8%, p=0.616), and mosaicism rate (16.5% vs. 15.9%, p=0.746) were all comparable between the two groups. Results of multivariate logistic regressions revealed no association between SARS-CoV-2 infection and euploidy rate, aneuploidy rate, or mosaicism rate. Similarly, no association was detected between the time interval of infection and oocyte retrieval (≤30 days, 31-60days, 61-90 days, 91-120 days, or ≥ 120 days prior to oocyte retrieval) and euploidy rate. Limitations, reasons for caution The retrospective nature of the study and limited sample size for subgroup analysis limits the generalizability of the findings. Other potential confounders, such as the level of SARS-CoV-2 antibody, symptoms of infection, are needed to be taken into consideration as well. Large-scale prospective studies are warranted to confirm the conclusion. Wider implications of the findings Our study demonstrated that SARS-CoV-2 infection before oocyte retrieval had no detrimental impact on embryo euploidy rate, indicating that cycle cancellation due to SARS-CoV-2 infection may not be necessary. Trial registration number Not Applicable

O-040 Pro -better late than never

Abstract In IVF, blastocysts developed on Day5-6 are typically selected for transfer, cryopreservation, or biopsy, while embryos that do not reach this developmental stage before 144 hours post-insemination (hpi) are often discarded. Recently, there has been an increased adoption of blastocyst culture aimed at enhancing embryo selection potential and supporting a single embryo transfer approach. Consequently, the clinical significance of Day7 blastocysts (embryos reaching this stage beyond 144 hpi) has become a prominent topic of discussion, particularly in the context of treating patients with poor prognosis. Numerous studies worldwide have reported lower competence for these embryos, as evidenced by poorer morphological quality, higher aneuploidy rates, and lower implantation rates following both untested and euploid transfer. Nonetheless, a notable proportion of these blastocysts are euploid and result in healthy live births. While their clinical utilization may entail lower efficiency per transfer, it ultimately increases the cumulative live birth rate per cycle. However, most studies have encountered challenges due to diverse definitions of Day7, varying clinical settings, culture strategies, incubators, and local regulations. Presently in IVF, leveraging time-lapse technology (TLT), artificial intelligence (AI), and preimplantation genetic testing for aneuploidies (PGT-A) could standardize and enhance Day7 blastocyst characterization and clinical assessment. Consequently, we designed a study exclusively in freeze-all PGT-A cycles with vitrified-warmed euploid single embryo transfer after continuous culture in time-lapse incubators, trophectoderm biopsy without zona pellucida drilling on day3, comprehensive chromosome testing, confirming embryo morphological assessments through an AI-powered software, and utilizing this tool also to automate developmental timing annotations. Our analysis confirmed that all blastocysts were biopsied only after reaching an expansion level suitable for the procedure (approximately 24,000 µm²) and consistent across all embryos clustered every 12 hours in 6 groups (&amp;lt;120, 120-132, 132-144, 144-156, 156-168, and &amp;gt;168 hpi). Day7 blastocysts accounted for approximately 15% of all blastocysts obtained over 8 years, derived from older oocytes, exhibiting poorer quality according to both Gardner’s score and AI score, slower development from early stages, and accumulating delays across various intermediate processes like blastocyst expansion from tEB to the time of biopsy. They were less euploid and resulted in a lower live birth rate per euploid transfer. However, only the latter association was significant when adjusted for confounders (e.g., blastocyst quality). Comparing only embryos biopsied before 144 hpi versus embryos biopsied after this threshold, neither the euploidy nor the live birth rate were significantly different, supporting the extension of embryo culture beyond Day6. Overall, we estimated that Day7 embryos contribute to a relative increase of 4.4%, 13.7%, and 5.2% in the number of patients who achieved a live birth, who were not pregnant after the transfer of faster embryos, and who have supernumerary transferable embryos after a live birth, respectively. The main limitations of our investigation were its retrospective nature and the fact that retrospective associations do not provide evidence of causation. There might be a bias towards poor prognosis patients being subject to the transfer of Day 7 embryos, for instance. Lastly, more data are required regarding the putative impact of extended embryo culture including post-natal outcomes (reassuring to date), as well as the cost-effectiveness of this clinical choice. Considering the increasing personalization and patient-centeredness of IVF, where permitted by local regulations, the decision to culture embryos to Day7 should be based on a careful evaluation of couples’ reproductive history and future prognosis, and should be subject to a patient-centered decision-making process. In the future, AI can be harnessed to support IVF practitioners by objectifying the assessment of poor-quality and slow-growing embryos with measurable information and reliable predictions, thereby mitigating the inherent subjectivity of embryologists’ decisions.

P-228 Competence of injected MI versus MII sibling oocytes in terms of normal fertilization, blastocyst development and euploidy

Abstract Study question Is the injection of immature MI oocytes as effective as injection of their siblings mature MII oocytes regarding normal fertilization, blastocyst development and euploidy? Summary answer MI oocytes show a lower rate of fertilization, a similar blastulation rate, and a slightly lower rate of euploidy compared to their MII sibling oocytes. What is known already Although several studies have been performed on immature MI oocytes evaluating their developmental competence after intracytoplasmic sperm injection (ICSI), all have been performed on oocytes that extruded the first polar body by the time of injection. ICSI is typically performed on MII oocytes which have completed the process of maturation. Some laboratories also inject MI oocytes, nevertheless, they are generally not used due to the lack of required molecular and cellular changes to support normal development. However, there is limited research on the reproductive potential of oocytes in MI. Consequently, our current practices are founded on assumptions. Study design, size, duration This is a retrospective, observational study of 168 oocytes injected in MI and 839 sibling oocytes injected in MII from 82 ICSI cycles with Preimplantation Genetic Testing for Aneuploidies (PGT-A) performed in a single IVF clinic between April 2018 and December 2023. All PGT-A cycles included in this study contained at least one MI oocyte injected. Participants/materials, setting, methods After oocyte retrieval and denudation, the oocytes were classified as MII, MI or GV. MI oocytes with extruded polar body by the moment of ICSI were reclassified as MII. All MII and MI oocytes were inseminated and the embryos that reached blastocyst stage were biopsied on day 5, 6 or 7. Normal fertilization rate, blastocyst formation rate and euploidy rate were compared between MI-derived embryos and their MII-derived siblings. Main results and the role of chance A total of 1,094 oocytes were retrieved from 83 ICSI cycles with PGT-A, comprising 839 (76.7%) MII, 168 (15.4%) MI y 87 (7.9%) VG. The normal fertilization rate was significantly higher in oocytes injected at MII compared to MI (76.9% vs 53.0%, P &amp;lt; 0.001). The rates of abnormal fertilization in MII and MI oocytes were as follows: 1 PN 0.8% vs 0.6%, P = 0.342; 3PN 2.6% vs 1.2%, P = 0.075; 0 PN 19.7% vs 45.2%, P &amp;lt; 0.001. Interestingly, the blastulation rate of zygotes with normal fertilization was very similar between both groups (46.4% vs 43.8%, P = 0.708), as well as the proportion of biopsied blastocysts on day 5 (74.2% vs 71.8%, P = 0.858), on day 6 (23.1% vs 25.6%, P = 0.946), and on day 7 (2.7% vs 2.6%, P = 0.594). The euploidy rate of the 298 biopsied MII-derived blastocyst was 36.2%, compared with 23.1% of the 39 MI-derived blastocysts biopsied (P = 0.077). Despite the limited sample size, it is noteworthy that three out of the four euploid blastocysts derived from MI oocytes, which were transferred in single embryo transfers, successfully led to pregnancy resulting in one healthy live birth, one ongoing pregnancy and one miscarriage at 9 weeks of pregnancy. Limitations, reasons for caution While this study provides valuable insights into the developmental competence of MI oocytes, it is not exempt from certain limitations, such as its retrospective nature, limited sample size and ethical considerations regarding the injection of putative immature oocytes. Wider implications of the findings MI oocytes showed lower fertilization rates compared to their MII siblings. However, once fertilized, MI-derived embryos had similar blastulation rates and a trend towards lower euploidy rates. Our study suggests that MI oocytes may result in successful pregnancies and live birth, but further research is needed to validate these findings. Trial registration number Not applicable

P-647 Association between PCOS phenotype-D and euploid blastocyst rate per cohort of inseminated oocytes: a matched case-control study versus idiopathic infertile women

Abstract Study question Is there any association between PCOS phenotype-D and oocyte competence defined as euploid blastocyst rate (EBR) per cohort of inseminated oocytes? Summary answer Although higher fertilization and blastulation rates were reported in PCOS phenotype-D women versus idiopathic infertile patients, the EBR per cohort of inseminated oocytes was comparable. What is known already Several studies report poorer oocyte quality and cumulative-live-birth-rate (CLBR) in hyperandrogenic PCOS phenotypes, as defined according to the Rotterdam criteria. Increased androgen concentrations in follicular fluids are indeed associated with elevated serum-LH levels, which can block dominant follicle development inducing atresia and negatively impact fertilization rates and embryo development. Limited evidence exists in phenotype-D PCOS patients, namely women characterized by oligomenorrhea, ovarian PCO morphology and absence of hyperandrogenism. Here, we report the embryological and clinical outcomes in these women during ICSI cycles with preimplantation genetic testing for aneuploidies (PGT-A) at the blastocyst stage. Study design, size, duration Retrospective propensity score matched (PSM) case-control study. Among PGT-A cycles conducted by naïve patients with own oocytes (2013-2021), we excluded FNA/TESE. 58 phenotype-D PCOS patients were identified according to the Rotterdam criteria. These patients were matched for maternal age, number of cumulus-oocyte-complexes (COCs), and sperm quality, with 58 patients with idiopathic infertility, regular cycles, normal ovarian morphology, and no sign of clinical hyperandrogenism. The primary outcome was EBR per cohort of inseminated oocytes. Participants/materials, setting, methods GnRH-antagonist ovarian stimulation, ICSI, blastocyst biopsy, qPCR/NGS-analysis to assess uniform aneuploidies and vitrified-warmed single blastocyst transfers were conducted. The PCOS and control groups were similar for age (35.6±3.0 versus 36.0±3.9 years), COCs (23.1±6.7 versus 23.5±7.6), sperm factor, primary/secondary infertility, hormonal values, BMI (23.8±5.3 versus 22.0±2.8), and duration of infertility (3.6±2.2 versus 3.6±2.0 years). All intermediate embryological and clinical outcomes were assessed as secondary endpoints. Linear/logistic regressions adjusted for confounders were conducted to confirm statistically-significant differences. Main results and the role of chance No difference was reported in maturation rates, but women with PCOS showed better fertilization rates per cohort of inseminated oocytes (76.9±15.2% versus 67.3±20.4%, Mann-Whitney-U-test&amp;lt;0.01), and blastulation rates per cohort of 2PN-zygotes (52±20.4% versus 43.7±20.7%, Mann-Whitney-U-test=0.03). Eventually, PCOS patients obtained more blastocysts than controls (5.8±3.1 versus 4.5±2.9, Mann-Whitney-U-test=0.02), despite similar numbers of metaphase-II oocytes in the groups (16.5±6.1 versus 16.5±7.0). All differences remained significant after adjusting for maternal age and sperm factor. Nevertheless, the euploidy rates per cohort of biopsied blastocysts were similar, thus involving comparable EBR per cohort of inseminated oocytes (21.7±14.1% versus 17.2±16%, Mann-Whitney-U-test=0.12). More patients obtained ≥1 euploid blastocyst in the PCOS versus the control group (N = 56/58, 96% versus N = 47/58, 81%, Fisher’s-exact-test=0.02), independently from maternal age, semen quality, and number of inseminated oocytes (Odds-Ratio: 6.5, 95%CI:1.3-33.7, p = 0.03). Lastly, all clinical outcomes per first vitrified-warmed euploid transfer were similar, thereby involving comparable LBRs (N = 28/54, 51.9% versus N = 26/47, 55.3% in the PCOS and control groups, p = 0.8; Odds-Ratio adjusted for blastocyst quality and day: 1.19, 95%CI:0.5-2.7, p = 0.68). Limitations, reasons for caution Although clinical hyperandrogenism was absent in both groups, biochemical hyperandrogenism was not assessed. Nonetheless, this pilot study paves the way for future more detailed investigations. 24% of cycles in the PCOS group were not concluded, therefore a CLBR comparison would be biased and was not reported. Wider implications of the findings The lower developmental competence in the control group suggests oocyte quality issues, other than chromosomal, underlying their “unexplained infertility” condition. In phenotype-D PCOS women, IVF is effective. Since &amp;gt;50% of this subgroup of women had already failed multiple ovulation-induction and/or intrauterine-insemination attempts, an early referral to IVF deserves further investigations. Trial registration number Not applicable

O-065 PGT-A reveals triploid embryos among normally fertilized oocytes: Frequency and blastocyst features

Abstract Study question Is there any embryo parameter that could differentiate 2 pronucleus (PN) triploid from 2 PN euploid embryos? Summary answer Accuracy in the fertilization check is still necessary as 2 PN but triploid embryos are due mostly to retention of the second polar body (PB). What is known already Since blastocyst culture has evolved and the development of genetic technologies enables to know the karyotipe of the embryos, the concept of normal fertilization is being revised. Commonly, correct fertilization is denoted by the appearance of 2 PN 16-18h after insemination. Deviation from 2PN is considered evidence of abnormal fertilization and ploidy anomalies. However, not all oocytes exhibiting 2 PN are euploids. After performing NGS in trophectoderm biopsies for preimplantation genetic testing for aneuploidy (PGT-A), a percentage of embryos are categorized as triploids. Study design, size, duration Retrospective study including 1862 cycles from 1605 patients aged 18-45 years old who underwent PGT-A with NGS of trophectoderm biopsies in our IVF center from 2019 to 2023. From 6526 analyzed blastocysts in an independent Genetics laboratory, 59 were categorized as triploids. These 59 blastocysts were obtained from 57 PGT-A cycles and belonged to 54 women. In total, these patients had 266 biopsied blastocysts. From the remaining 207 embryos, 42 were called as euploids. Participants/materials, setting, methods In embryos cultured in time-lapse, fertilization was re-evaluated to check the appearance of 2PN and the second PB extrusion. Genetic triploid embryos were analysed in relation to the day of biopsy (day 5 vs day 6), the trophectoderm quality and the timing of the first cell divisions (time of cleavage from 2 to 6 cells: t2, t3, t4, t5, t6). Categorical variables are shown as rate. T-student tests were performed. P-value&amp;lt;0.05 was considered statistically significant. Main results and the role of chance The re-evaluation of the fertilization of the 59 triploids categorized as 2 PN revealed 50 oocytes 2 PN, 8 embryos 3 PN and 1 embryo 2 PN + 1 micronuclei configuration. Therefore, the prevalence of real triploidy in 2PN embryos was 0,8% (n = 50/6526; CI95%:0,6-1,0%). These data showed that 2PN zygotes may give rise to embryos with altered ploidy. From 27 triploid 2PN embryos was possible to access to the whole development time-lapse images. Just 33,3% of triploid embryos exhibited the extrusion of the second PB, while 100% of euploid sibling embryos showed this extrusion (N = 9/27 vs N = 24/24,;p&amp;lt;0,005). Comparing 2 PN triploid and the rest of the embryos from the same cohorts, there were no differences regarding the day of biopsy (N = 31/176 day 5 biopsy, 17.6% vs N = 19/81 day 6 biopsy, 23.5%; p &amp;gt; 0.05). On the contrary, a worse blastocyst quality showed a significant relation with triploidy (N = 23/161,14,2% of good quality embryos are triploid vs N = 27/96, 38,6% of fair quality embryos are triploids; p:0.006).Embryos cleavage time points up to 6-cell stage did not show any significative difference between triploid and euploid embryos (t2: 27.36h vs 25.8h; t3: 38.5h vs 35.6h; t4 39.4h vs 37.2h; t5 52.8h vs 47.0h; t6 56.2h vs 52.1h; all comparisons p &amp;gt; 0.05). Limitations, reasons for caution The incidence of triplody from 2PN zygotes may vary among IVF laboratory settings. The small sample size may be responsible of no difference in morphokinetics. Wider implications of the findings Fertilization check should persist in IVF procedures. Special consideration should be given to the second PB extrusion as triploidy is the most common form of aneuploidy observed in the first trimester miscarriages. The role of diploid spermatozoa, the size of the pronucleus and location should be explored in further studies. Trial registration number NOT APPLICABLE

P-293 Influence of the endometrial microbiota composition on the clinical outcomes of egg donation PGT-A cycles with controlled endometrial receptivity

Abstract Study question Does the endometrial microbiota composition and diversity influence embryo implantation and pregnancy evolution in assisted reproduction treatment (ART) cycles? Summary answer Endometrial microbiota composition influences ART success. Detection of endometrial pathogens is associated with poor outcomes whereas sterile endometria show the highest pregnancy and live-birth rates What is known already The endometrial microbiota has emerged as a possible influencing factor in the results of ART. Recent research suggests its impact on female reproductive health, particularly in patients with chronic endometritis (CE), where the presence of microbial pathogens associated with this condition has been linked to infertility. In turn, the bioregulatory role of species of Lactobacillus in this tissue has been explored, although its essentiality or benefit for female reproductive function continues to be topics of debate. Study design, size, duration This is a case-control retrospective study analysing for the first time the influence of the endometrial microbiota composition on the clinical outcomes of 220 women undergoing egg donation cycles with Preimplantation Genetic Testing for Aneuploidy (PGT-A) and controlled endometrial receptivity between March 2016 and April 2021 in IVF-Life Alicante (Spain). ART results after the transfer of a single euploid blastocyst in the WOI of patients with different endometrial microbiota profiles were analysed and compared. Participants/materials, setting, methods Presence of 18 microbial CE pathogens and 4 Lactobacillus species was determined by high-throughput qPCR (MicrobioMap®, iGLS) in endometrial samples obtained during the WOI of a hormone replacement therapy cycle. In all cases, PGT-A by next generation sequencing (NGS) (EmbryoMap, Vitrolife) and study of endometrial receptivity by gene expression analysis (ER Map, iGLS) were performed. Clinical outcomes (β-hCG+, β+ and live birth, LB) in relation to the endometrial microbiota profile were analysed and compared. Main results and the role of chance In the study, 31.8% of patientś endometria were identified without microbial detection, 40% exclusively with Lactobacillus, 13.2% with pathogens only, and 15% with both. Clinical results revealed significant differences in β+ rates among the groups (p &amp;lt; 0.05). The absence of microorganisms was associated with higher success rates (β + 72.9%), while the presence of pathogens significantly reduced pregnancy success (β + 41.4%). A similar trend was observed in LB rates, although it did not reach statistical significance (44.3% and 24.1%, respectively). The presence of Lactobacillus alongside pathogens improved clinical outcomes (β + 57.6% LB 48.5%). Interestingly, exclusive presence of Lactobacillus showed lower implantation rates than patients without microbial detection (β + 58%). These findings highlight the impact of microbial composition on the clinical outcomes of ART cycles, underlining the association between endometrial microbiota patterns and pregnancy success. Limitations, reasons for caution This study is constrained by its retrospective nature, emphasizing the need for further validation through randomized controlled trials, non-selection studies, or other investigative approaches to confirm the extent of any clinical benefits. Endometrial biopsies were obtained transcervically, while executed with utmost care, risk of contamination cannot be completely excluded. Wider implications of the findings The composition and diversity of the endometrial microbiota is key for ART success. A sterile endometrial environment offers optimal conditions for implantation and pregnancy. The study highlights the potential of Lactobacillus in counteracting the negative impact of pathogenic presence. Trial registration number not applicable

Inflammatory Changes after Medical Suppression of Suspected Endometriosis for Implantation Failure: Preliminary Results.

Unexplained euploid embryo transfer failure (UEETF) is a frustrating and unanswered conundrum accounting for 30 to 50% of failures in in vitro fertilization using preimplantation genetic testing for aneuploidy (PGT-A). Endometriosis is thought by many to account for most of such losses and menstrual suppression or surgery prior to the next transfer has been reported to be beneficial. In this study, we performed endometrial biopsy in a subset of women with UEETF, testing for the oncogene BCL6 and the histone deacetylase SIRT1. We compared 205 PGT-A cycles outcomes and provide those results following treatment with GnRH agonist versus controls (no treatment). Based on these and previous promising results, we next performed a pilot randomized controlled trial comparing the orally active GnRH antagonist, elagolix, to oral contraceptive pill (OCP) suppression for 2 months before the next euploid embryo transfer, and monitored inflammation and miRNA expression in blood, before and after treatment. These studies support a role for endometriosis in UEETF and suggest that medical suppression of suspected disease with GnRH antagonist prior to the next transfer could improve success rates and address underlying inflammatory and epigenetic changes associated with UEETF.

The comparision among euploidy of preimplantation blastocysts in different controlled ovary stimulation (COH) protocols.

To compare differences in euploidy rates for blastocysts in preimplantation genetic testing for aneuploidy (PGT-A) cycles after gonadotropin-releasing hormone agonist (GnRH-a) long and short protocols, GnRH-antagonist (GnRH-ant) protocol, progestin-primed ovarian stimulation and mild stimulation protocols, and other ovary stimulation protocols. This was a retrospective cohort study from the Assisted Reproductive Medicine Department of Shanghai First Maternity and Infant Hospital. A total of 1657 PGT-A cycles with intracytoplasmic sperm injection after different controlled ovary hyperstimulation protocols were analyzed, and a total of 3154 embryos were biopsied. Differences in euploidy rate per embryo biopsied, embryo euploidy rate per oocyte retrieved and cycle cancellation rate were compared. For the PGT-A cycles, the euploidy rate per embryo biopsied was lower in the GnRH-ant protocol than in the GnRH-a long protocol (53.26 vs. 58.68%, respectively). Multiple linear regression showed that the GnRH-ant protocol was associated with a lower euploidy rate per embryo biopsied (β = -0.079, p = 0.011). The euploidy rate per embryo biopsied was not affected by total gonadotropin dosage, duration of stimulation and number of oocytes retrieved. The embryo euploidy rate per oocyte retrieved was similar in all protocols and was negatively correlated with the total number of oocytes retrieved (β = -0.003, p = 0.003). Compared with the GnRH-a long protocol, the GnRH-ant protocol was associated with a lower euploidy rate per embryo biopsied. The total gonadotropin dosage, duration of stimulation and number of oocytes retrieved did not appear to significantly influence euploidy rates.

Analysis of related factors influencing the detection rate of mosaic embryo and the pregnancy outcomes with mosaic embryo transfers

Objective: To explore the related factors influencing the detection rate of mosaic embryo and the pregnancy outcomes of mosaic embryo transfer in preimplantation genetic testing for aneuploidy (PGT-A) based on next generation sequencing (NGS) technology. Methods: A retrospective study was performed to analyze the clinical data of patients in 745 PGT-A cycles from January 2019 to May 2023 at Chongqing Health Center for Women and Children, including 2 850 blastocysts. The biopsy cells were tested using NGS technology, and the embryos were divided into three groups based on the test results, namely euploid embryos, aneuploid embryos and mosaic embryos. The influence of population characteristics and laboratory-related parameters on the detection rate of mosaic embryo were analyzed, and the pregnancy outcomes of 98 mosaic embryo transfer cycles and 486 euploid embryo transfer cycles were compared during the same period, including clinical pregnancy rate and live birth rate. Results: Among the embryos tested (n=2 850), the number and proportion of euploid embryos, aneuploid embryos and mosaic embryos were 1 489 (52.2%, 1 489/2 850), 917 (32.2%, 917/2 850) and 444 (15.6%, 444/2 850), respectively. Among mosaic embryos, 245 (55.2%, 245/444) were segmental mosaic embryos, 118 (26.6%, 118/444) were whole-chromosome mosaic embryos, and 81 (18.2%, 81/444) were complex mosaic embryos. NGS technology was performed in 4 genetic testing institutions and the detection rate of mosaic embryo fluctuated from 13.5% to 27.0%. The distributions of female age, level of anti-Müllerian hormone, PGT-A indications, ovulation-inducing treatments, gonadotropin (Gn) dosage, Gn days, inner cell mass grade, trophectoderm cell grade, genetic testing institutions and developmental stage of blastocyst were significantly different among the three groups (all P<0.05). Multi-factor analysis showed that the trophectoderm cell grade and genetic testing institutions were significantly related to the detection rate of mosaic embryo; compared with the trophectoderm cell graded as A, the detection rate of mosaic embryo was significantly increased in the trophectoderm cell graded as B-(OR=1.59, 95%CI: 1.04-2.44, P=0.033); compared with genetic testing institution a, the detection rate of mosaic embryo was significantly higher (OR=2.89, 95%CI: 2.10-3.98, P<0.001) in the testing institution c. The clinical pregnancy rate and live birth rate with mosaic embryos transfer were significantly lower than those of euploid embryos transfer (clinical pregnancy rate: 51.0% vs 65.2%, P=0.008; live birth rate: 39.4% vs 53.2%, P=0.017). After adjustment for age, PGT-A indications, trophectoderm cell grade and days of embryo culture in vitro, the clinical pregnancy rate and live birth rate with mosaic embryos transfer were significantly lower than those of euploid embryos transfer (clinical pregnancy rate: OR=0.52, 95%CI: 0.32-0.83, P=0.007; live birth rate: OR=0.50, 95%CI: 0.31-0.83, P=0.007). Conclusions: The trophectoderm cell grade and genetic testing institutions are related to the detection rate of mosaic embryo. Compared with euploid embryos transfer, the clinical pregnancy rate and live birth rate with mosaic embryos transfer are significantly reduced. For infertile couple without euploid embryos, transplantable mosaic embryos could be recommended according to the mosaic ratio and mosaic type in genetic counseling to obtain the optimal pregnancy outcome.

Preimplantation genetic testing for aneuploidy: predictive embryonic factors.

In a preimplantation genetic testing for aneuploidy (PGT-A) cycle, does the blastocyst quality before biopsy, or the day of biopsy, or the embryo hatching status have an impact on either euploidy or the rate of embryo survival after freezing? This was a retrospective study including 6130 biopsied blastocysts coming from 1849 PGT-A cycles performed in our center (2016-2022). Embryos were categorized according to the inner cell mass and trophectoderm quality, using Gardner's scoring (excellent: AA; good: AB, BA, BB; poor: AC, CA, BC, CB, CC); the day of biopsy (5 or 6); and their hatching status (fully hatched blastocysts [FHB] or non-fully hatched blastocysts [nFHB]). The independent relationship between each group and both euploidy and survival rate was assessed. Excellent-quality embryos were more euploid than both good- and poor-quality embryos (52.69%, 39.69%, and 26.21%; p < 0.001), and day 5-biopsied embryos were more euploid than day 6-biopsied embryos (39.98% and 34.80%; p < 0.001). Survival rates of excellent-quality (92.26%) and good-quality (92.47%) embryos were higher than survival rates in the poor-quality group (84.61%) (p = 0.011 and p = 0.002). Day 5-biopsied embryos survived better than day 6-biopsied embryos (93.71% vs. 83.69%; p < 0.001) and FHB had poorer survival than nFHB (78.61% vs. 93.52%; p < 0.001). Excellent-quality and day 5-biopsied embryos are more prone to be euploid than good and poor or day 6-biopsied embryos, respectively. Poor-quality, day 6-biopsied embryos, and FHB have significantly lower survival after biopsy and vitrification.

Correlation between controlled ovarian stimulation protocols and euploid blastocyst rate in pre-implantation genetic testing for aneuploidy cycles

BackgroundSeveral studies have explored which COS protocol yields a higher blastocyst euploidy rate, but findings have been inconsistent. The present study aimed to explore whether controlled ovarian stimulation (COS) protocols was associated with euploid blastocyst rate in pre-implantation genetic testing for aneuploidy (PGT-A) cycles.MethodsThe study was a retrospective study where data were obtained from three reproductive medicine centers. The study included PGT-A cycles with the GnRH-a, GnRH-ant, or PPOS protocols, and the data on patient demographics, protocols, and embryonic outcomes were collected for the PGT-A cycles performed between January 2019 and August 2022.ResultsThis study included 457 PGT-A cycles from three reproductive medicine centers, with 152, 126, and 179 cycles performed using the PPOS, GnRH-a, and GnRH-ant protocols, respectively. The baseline characteristics of the three groups show no significant differences were observed in female BMI, infertility type, and infertility duration among the PPOS, GnRH-a, and GnRH-ant protocol groups. The study found no significant association between Gn dosage, Gn duration, and blastocyst euploidy. The mean number of euploidy blastocysts in PPOS protocol was significantly lower than that of GnRH-a protocol and GnRH-ant protocol (0.75 ± 0.92 vs. 1.79 ± 1.78 vs. 1.80 ± 1.67). The euploidy rate per biopsy blastocyst (48.4% vs. 49.1% vs. 33.1%), per oocyte retrieved (15.0% vs. 14.7% vs. 10.5%), and per MII oocyte (17.7% vs. 16.4% vs. 11.7%) were significantly higher in the cycles using the GnRH-ant and GnRH-a protocols than that of PPOS protocol group. Regression analyses indicated that, compared with the PPOS protocol, the GnRH-ant protocol was positively associated with the euploid blastocyst rate and the mean number of euploid blastocysts, whereas the GnRH-a protocol showed no such relationship.Limitations and reasons for cautionThe main limitation of this study was the retrospective design. Although this study also used other tests to account for confounding factors and reduce potential bias, multiple tests have its own weaknesses.ConclusionsGnRH-ant protocol was the most effective for PGT-A cycles. The findings emphasize the need for personalized treatment strategies, considering patient demographics, and optimizing COS protocols to enhance the chances of successful outcomes in ART procedures.

Higher live birth rates are associated with a normal body mass index in preimplantation genetic testing for aneuploidy frozen embryo transfer cycles: a Society for Assisted Reproductive Technology Clinic Outcome Reporting System study

To determine whether body mass index (BMI) was associated with live birth in patients undergoing transfer of frozen-thawed preimplantation genetic testing for aneuploidy (PGT-A) embryos. Retrospective cohort study of cycles reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System. All autologous and donor recipient PGT-A-tested cycles reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System from 2014 to2017. Body mass index. The primary outcome measure was the live birth rate, and the secondary outcome measures were the clinical pregnancy and biochemical pregnancy rates. Multivariable generalized additive mixed models and log-binomial models were used to model the relationship between BMI and outcome measures. A total of 77,018 PGT-A cycles from 55,888 patients were analyzed. Of these cycles, 70,752 were autologous, and 6,266 were donor recipient. In autologous cycles, a statistically significant and clear nonlinear relationship was observed between the BMI and live birth rates, with the highest birth rates observed for the BMI range of 23-24.99 kg/m2. When using 23-24.99 kg/m2 as the referent, other BMI ranges demonstrated a lower probability of live birth and clinical pregnancy that continued to decrease as the BMI moved further from the reference value. Patients with a BMI of <18.5 kg/m2 had a 11% lower probability of live birth, whereas those with a BMI of ≥40 kg/m2 had a 27% lower probability than the referent. A normal-weight BMI range of 23-24.99 kg/m2 was associated with the highest probability of clinical pregnancy and live birth after a frozen-thawed PGT-A-tested blastocyst transfer in both autologous and donor recipient cycles. A BMI outside the range of 23-24.99 kg/m2 is likely associated with a malfunction in the implantation process, which is presumed to be related to a uterine factor and not an oocyte factor, as both autologous and donor recipient cycle outcomes were associated similarly with the BMI of the intended parent.