Embryo Aneuploidy Rate Research Articles

P-199 The development time of good quality blastocysts is dependent on their genetic status in patients over 36 years old

Abstract Study question Is there any difference in PGT-A results between good quality blastocysts depending on whether they reach this stage on the fifth or sixth day? Summary answer In patients over 36 years old, there is a significantly higher rate of aneuploidy in embryos that reach the blastocyst stage on Day 6. What is known already The level of chromosomal abnormalities in embryos increases with maternal age, as indicated by PGT-A data. Embryo quality also correlates with aneuploidy level. The normal timeframe for blastocyst formation is considered to be between the fifth and sixth day of development. In this study, the genetic status of good quality blastocysts was examined to determine a difference in the aneuploidy rate between blastocysts formed on the fifth day compared to those formed on the sixth day.This information could provide insights into the optimal timing for blastocyst formation and its relationship to genetic abnormalities. Embryo quality also correlates with aneuploidy level Study design, size, duration The retrospective study included 513 good quality blastocysts (3-4, A-B according to the Gardner classification) after trophectoderm biopsy and obtained from fresh oocytes of 141 patients aged 23-45 years. The PGT-A data were analyzed. The analysis considered the age of the patients, with one group of patients younger than 36 years old (35 patients, 174 blastocysts), and another group aged 36 years and older (106 patients, 339 blastocysts). Participants/materials, setting, methods Trophectoderm biopsy was performed on good quality embryos as they progressed in development, either on the fifth or sixth day. PGT-A was conducted using the NGS method, and the data was processed using the chi-square test. Main results and the role of chance Among patients younger than 36 years old, 58.5% of good quality blastocysts formed by the fifth day of development. In comparison, among patients 36 years old and older, 43.0% of good quality blastocysts formed by the fifth day. The difference in the growth rate of blastocysts of the same quality between the age groups was statistically significant (p > 0.01). In patients younger than 36 years old, 75.0% of blastocysts formed by the fifth day and 66.7% of blastocysts formed by the sixth day were euploid (with no significant difference). In patients 36 years old and older, 50.5% of blastocysts formed by the fifth day were euploid, while only 19% of blastocysts formed by the sixth day were euploid. This difference in euploidy rates between the fifth- and sixth-day blastocysts was statistically significant (p > 0.01). Limitations, reasons for caution The study was conducted with a relatively small sample size, which may limit the generalizability of the results. A larger and more diverse sample would be beneficial to confirm the findings. Wider implications of the findings In patients over 36 years of age, the majority of blastocysts develop by Day 6, and there is a significant increase in aneuploidy level. This suggests that there may be a higher risk of chromosomal abnormalities in embryos that take longer to develop into blastocysts in this group. Trial registration number Not applicable

O-239 Automation in the embryology laboratory

Abstract Most processes in an IVF laboratory are performed manually by technicians and embryologists, such as tracking and prepare dishes, pipetting of gametes and embryos from one dish to another, loading freezing straws, and operating micromanipulators for ICSI or biopsy. In most centres doctors manage hormonal stimulation based on their own learned experience or at most of their team. This results in significant variability in pregnancy outcomes from centre to centre and even operator to operator. For example, centres can be compared based on egg donor cycles, which are all young and fertile patients selected in similar ways in most centres. But even In egg donor cycles, embryo aneuploidy rates vary 20% to 60% (1) while pregnancy rates fluctuate from 10% to 80% depending on the clinic (2). Furthermore, although large amounts of data are generated from >2M procedures of IVF a year worldwide, most of it is siloed in each centre in a myriad of EMRs or worse, spreadsheets, impossible to query globally. The lack of a massive dataset to query and the absence of a constant baseline in pregnancy outcomes makes introducing new innovations harder to determine if they work or not. Automation should allow constant results with similar results clinic to clinic, especially desirable for networks to offer a consistent service across centres. By reducing the reliance on highly skilled manual labour, which is facing a global scarcity, automation has the potential to offer more people affordable treatment. Moreover, the utilization of automation generates vast amounts of data, with machines sharing information to inform medical decisions based on millions of standardized treatments, surpassing the insights of individual physicians. This data-driven approach also establishes a stable foundation for innovation by minimizing human variables. Advancements in Affordable Robotics, coupled with high precision and miniaturization, alongside the evolution of software, are transforming robots into versatile tools akin to smartphones. This transformation encompasses various fields, including microfluidics, miniaturized imaging systems, Artificial Intelligence, and the Internet of Things (IoT). Some automation has already occurred, such time-lapse incubators with imaging allowing for AI classification of embryos, or witness systems. Although historical lack of government funding and current trends of consolidation of clinics into networks, may slow innovation, numerous startup companies are actively developing automation solutions for IVF laboratory operations and patient management. These solutions range from tools for remote patient monitoring to automating processes such as egg denudation, sperm analysis, oocyte and embryo vitrification and warming, as well as procedures like automated ICSI and in vitro fertilization. Furthermore, artificial intelligence is being harnessed for tasks like embryo selection and hormonal stimulation, with groundbreaking concepts like artificial uterus also under exploration. Nonetheless, the objective of automation should be to enhance the abilities of the embryologist, not to reduce their need. Once the process has been standardized, it should pave the way for the creation of novel and more interesting tasks. This empowers the embryologist to engage in higher complexity or more high touch tasks, rather than merely replacing labor.

Excessive Exogenous Gonadotropins and Genetic and Pregnancy Outcomes After Euploidy Embryo Transfer

The safety of exogenous gonadotropin treatment, based on its effect on embryos and pregnancy outcomes, remains inconclusive. To evaluate the associations of different doses and durations of gonadotropins with embryonic genetic status and pregnancy outcomes after euploid embryo transfer in couples with infertility. This study was a post hoc analysis of a multicenter randomized clinical trial (RCT) conducted at 14 reproductive centers throughout China from July 2017 to June 2018 that evaluated the cumulative live birth rate with or without preimplantation genetic testing for aneuploidy (PGT-A) among couples with infertility and good prognosis. The PGT-A group from the original RCT was selected for secondary analysis. Patients were divided into 4 groups according to the total dosage of exogenous gonadotropins and treatment duration: group 1 (≤1500 IU and <10 days), group 2 (≤1500 IU and ≥10 days), group 3 (>1500 IU and <10 days), and group 4 (>1 500 IU and ≥10 days). Group 1 served as the control group. Data were analyzed from June through August 2023. Blastocyst biopsy and PGT-A. The primary outcomes were embryonic aneuploidy, embryonic mosaicism, and cumulative live birth rates after euploid embryo transfer. A total of 603 couples (mean [SD] age of prospective mothers, 29.13 [3.61] years) who underwent PGT-A were included, and 1809 embryos were screened using next-generation sequencing. The embryo mosaicism rate was significantly higher in groups 2 (44 of 339 embryos [13.0%]; adjusted odds ratio [aOR], 1.69 [95% CI, 1.09-2.64]), 3 (27 of 186 embryos [14.5%]; aOR, 1.98 [95% CI, 1.15-3.40]), and 4 (82 of 651 embryos [12.6%]; aOR, 1.60 [95% CI, 1.07-2.38]) than in group 1 (56 of 633 embryos [8.8%]). There were no associations between gonadotropin dosage or duration and the embryo aneuploidy rate. The cumulative live birth rate was significantly lower in groups 2 (83 of 113 couples [73.5%]; aOR, 0.49 [95% CI, 0.27-0.88]), 3 (42 of 62 couples [67.7%]; aOR, 0.41 [95% CI, 0.21-0.82]), and 4 (161 of 217 couples [74.2%]; aOR, 0.53 [95% CI, 0.31-0.89]) than in group 1 (180 of 211 couples [85.3%]). In this study, excessive exogenous gonadotropin administration was associated with increased embryonic mosaicism and decreased cumulative live birth rate after euploid embryo transfer in couples with a good prognosis. These findings suggest that consideration should be given to minimizing exogenous gonadotropin dosage and limiting treatment duration to improve embryo outcomes and increase the live birth rate. ClinicalTrials.gov Identifier: NCT03118141.

High sperm DNA fragmentation increased embryo aneuploidy rate in patients undergoing preimplantation genetic testing

Is high sperm DNA fragmentation (SDF) associated with a high embryonic aneuploidy rate in patients undergoing intracytoplasmic sperm injection (ICSI)-preimplantation genetic testing (PGT)? This was a retrospective study of 426 couples with normal karyotypes undergoing ICSI-PGT at the authors' centre from March 2017 to March 2021. SDF was assessed using the sperm chromatin structure assay. The population was divided into low and high SDF groups according to cut-off values found by the receiver operating characteristic (ROC) curve. A 1:1 ratio propensity score matching (PSM) method was used to control for potential confounding factors, and a generalized linear mixed model was established to evaluate the relationship between SDF and the embryonic aneuploidy rate. The ROC curve indicated a threshold of 30%. In total, 132 couples were included after PSM, and the high SDF group (>30%) had significantly higher SDF (40.74% ± 9.78% versus 15.54% ± 7.86%, P < 0.001) and a higher embryo aneuploidy rate (69.36% versus 53.96%, P < 0.001) compared with the low SDF group (≤30%). The two pronuclear fertilization rate, cleavage rate, rate of high-quality embryos at day 3 rate, blastocyst rate, biochemical pregnancy rate, clinical pregnancy rate, miscarriage rate, live birth rate, caesarean section rate, preterm birth rate, singleton rate and low birthweight rate were similar in both groups (P > 0.05). After PSM, SDF > 30% was significantly correlated with an increased embryo aneuploidy rate after adjusting for all confounding variables (adjusted odds ratio 1.70, 95% CI 1.00-2.88, P = 0.049). SDF > 30% was associated with an increased embryo aneuploidy rate in couples with normal karyotypes undergoing PGT, but did not affect embryonic and clinical outcomes after transfer of euploid embryos.

O-299 Sperm DNA fragmentation by TUNEL influences live birth in egg recipients after euploid embryo transfer

Abstract Study question Does sperm DNA fragmentation (SDF) by TUNEL affect reproductive success measured as live birth rate (LBR) in egg recipients after euploid embryo transfer? Summary answer SDF increases miscarriage rates in egg recipients with PGT-A. Therefore, live birth rates depends on sperm DNA damage in egg recipients after euploid embryo transfer. What is known already Sperm DNA integrity is important for optimal fertilisation, implantation and pregnancy. Although controversial, several studies have shown that sperm DNA fragmentation correlates with adverse pregnancy outcomes in infertile men. Ooplasmic sperm DNA fragmentation repair mechanisms may occur in female gametes, mainly in young women. However, research on the impact of DNA fragmentation on LBR are limited. Also, chromosomally normal embryos analysed by PGT-A offers opportunity to isolate female factor and study male factor. The aim of this study is to assess whether high level of semen DNA damage has an impact on reproductive outcomes in terms of live birth rate. Study design, size, duration This is a retrospective study of 467 PGT-A cycles in egg recipients. The study population consists of infertile couples for euploid embryo transfer (February 2017-November 2022). Semen samples were obtained to measure DNA damage from 447 men. PGT-A was performed in 1831 blastocysts. Trophectoderm biopsies (d5/d6 blastocysts) were analysed by NGS (Veriseq Illumina). Embryos were frozen and 568 blastocysts transferred in the subsequent cycle. Conventional hormone replacement was used for endometrial preparation in recipient patients. Participants/materials, setting, methods Cohort study with 447 infertile couples attending to private fertility clinic undergoing ART with their autologous semen, donated oocytes and PGT-A. SDF was measured by Terminal-deoxyribonucleotidyl-ARTSferase-mediated dUTP Nodule End Labelling (TUNEL) assay using the FITC-labelled-dUTP in situ cell death detection kit (Roche). The cohort was divided into two groups according the DNA fragmentation index (DFI): high SDF group (DFI&amp;gt;20%) and normal SDF group (DFI≤20%). To evaluate reproductive outcomes Chi-square and Linear regression tests were used. Main results and the role of chance Of the 447 couples included (average paternal age 41.29 + 7.32 years), 66.5% of male partners had normal semen parameters. We reported high sperm DNA fragmentation in 8% of patients. Overall, the embryo aneuploidy rate was 31.7%. For the further statistical analysis confounding factors such as, female and male age, embryo quality, day of embryo biopsy were included. PGT-A analysis showed an aneuploidy rate of 32.1% in the high DNA fragmentation group and 30.3% in the normal DNA fragmentation group (p = 0.453). Regarding clinical data, the overall implantation rate was 34.9%. There was no significant difference between elevate DNA fragmentation and normal DNA fragmentation with respect to biochemical miscarriage rate (4.3% vs 7.6%, p = 0.799). Although not significant differences between groups, a lower implantation rate near to reach significance was found in the high SDF group (20.0% vs 34.4%, p = 0.050). Pregnancy and clinical pregnancy rates were significantly lower in the high DNA fragmentation group (26.1% vs 44.9%, p = 0.042; 21.7% vs 31.3%, p = 0.044;), respectively. Also, miscarriage rate was significantly higher in the high SDF group (40% vs 12.5%, p = 0.014). Therefore, the live birth rate was significantly lower in the high SDF group (13.0% vs 32.6%, p = 0.024). Limitations, reasons for caution Larger studies including a higher number of samples are needed to confirm the correlation observed between LBR in eggs recipients with semen DNA fragmentation. Those patients with a DFI higher than control values should be treated with antioxidants. The pregnancy outcomes should be analyzed after treatment of DNA fragmentation. Wider implications of the findings Our findings suggest that autologous semen DNA fragmentation influence in live birth rate in egg recipients. Our data show that live birth rates decreased in patients with a high DFI after PGT-A. This study confirms published studies in the literature showing that ART outcomes are affected by sperm DNA fragmentation. Trial registration number Not Applicable

O-184 Validation of a model capable of estimating the minimum number of mature oocytes needed to obtain at least one euploid blastocyst regarding female age

Abstract Study question Which is the minimum number of mature oocytes needed to obtain at least one euploid blastocyst regarding female age in In Vitro Fertilization (IVF) treatments? Summary answer The validated model estimates with a 74% accuracy the probability of having one euploid blastocyst regarding the number of mature oocytes and female age. What is known already Female age is significantly and directly related to embryo aneuploidy rates, thus lowering the chances of success in IVF treatments. The current delay in motherhood has led to a large proportion of women of advanced maternal age seeking infertility treatment. The aim of the present study is to determine the number of metaphase II (MII) oocytes needed to obtain at least one euploid blastocyst regarding female age. This information will help to decide the best strategy for each patient, taking also into account other variables such as ovarian reserve, semen quality and oocyte quality. Study design, size, duration Retrospective analysis of IVF cycles with pre-implantational genetic testing for aneuploidies (PGT-A) performed over the last 5 years in an infertility clinic in Spain, from January 2017 to March 2022. Participants/materials, setting, methods Patients undergoing an IVF cycle in an infertility clinic with own or donated oocytes, regardless semen origin. Only trophoectoderm biopsies performed on day 5 or 6 of development and analyzed using Next Generation Sequencing (NGS) were included. PGT-A was used for reasons such as advanced maternal age, implantation failure and recurrent miscarriage. PGT-A cycles due to a known abnormal karyotype were excluded. Endpoints were analized using binary logistic regression models. Main results and the role of chance A total of 3840 IVF-PGT-A cycles meeting the inclusion criteria were performed in the study period. Of them, 939 cycles were discarded due to the absence of any biopsied/analyzed embryo (final sample size=2901). A model for the probability of having at least one euploid blastocyst (pEB) regarding female age and the number of MII oocytes retrieved was created with 80% of the sample (n = 2320) and validated in the remaining 20% (n = 581). The validation of this model showed that it was capable of estimate with an accuracy of 73.88%. The pEB was directly related to the number of MII oocytes retrieved (odds ratio (OR) 1.130, confidence interval (IC) 95% (1.110-1.150); p &amp;lt; 0.001), but indirectly related to female age (OR 0.751, IC95% (0.725-0.778); p &amp;lt; 0.001). The ROC curve showed a significant predictive value of the number of MII oocytes (area under the curve (AUC):0.8041 (0.7882-0.82)) for this model. A mathematical formula was created for the calculation of pEB using this model. The number of MII oocytes needed for a pEB of 75% regarding female age (female age:number MII) was 35:6, 36:9, 37:12, 38:15, 39:18, 40:21, 41:24, 42:27, 43:30, 44:32, 45:35, 46:38, 47:41, 48:44, 49:47, 50:50. Limitations, reasons for caution The main limitation of this study is its retrospective design. In addition, it’s important to keep in mind that many other variables should be taken into consideration along with maternal age in the assessment of the number of oocytes needed to obtain at least one euploid blastocyst in IVF treatments. Wider implications of the findings Results from this study may constitute a useful tool for both clinical and patient. The clinician may be able to better decide the best strategy for each patient, while the patient will understand more easily this information, helping her morally with the treatment. Trial registration number 2204-VLC-040-CR

P-696 Identification of novel candidate genes associated with meitotic aneuploidy in human embryos by whole-exome sequencing (WES)

Abstract Study question Can certain genetic variants in women cause a genetic predisposition to aneuploidy? Summary answer Our results suggest that the maternal variants identified in genes regulating meiotic processes could be useful genetic biomarkers for predicting a predisposition to embryonic aneuploidies. What is known already Errors in chromosome segregation during meiosis as chromosome synapsis, crossing-over and spindle building, occur frequently in human oocytes and cause aneuploidy in embryos. These errors increase dramatically in the oocytes of older women. However, the rate of producing aneuploidy oocytes varies among IVF patients for a given age. Recent publications have identified genetic variants that are crucial for producing healthy oocytes in female IVF patients. The association between maternal genetic variants and embryonic aneuploidy risk suggests the potential of using genomic data to predict embryonic aneuploidy risk. Our aim was to identify novel variants and candidate genes for embryonic aneuploidy. Study design, size, duration A prospective observational cohort study was done including 127 trophoectoderm biopsies from 29 couples who performed whole-exome sequencing (WES) and PGT-A between November 2019 and March 2022. Women were 35 years old or younger and normal karyotype for men and women. Patients were divided in two groups according to the embryo aneuploidy rate expected by their maternal age: ≤ 50% of aneuploid blastocysts as control group(n = 14), and ≥ 50% of aneuploid blastocysts as study group(n = 15). Participants/materials, setting, methods WES was performed using Trusight One Expanded Sequencing Panel (Illumina®). The following criteria were used for filtering and annotation of candidate variants: (1) minor allele frequency (MAF) &amp;lt;0.05 in the gnomAD and 1000 genomes, (2) variants in genes previously associated with chromosome segregation, chromatin cohesion, meiosis and cell division processes, (3) exonic/splicing boundaries variants, (4) variants having potentially strong/moderate functional effects on the protein evaluated using three in silico prediction algorithms (SIFT, PolyPhen-2 and MutationTaster). Main results and the role of chance Overall, the mean female and male age was 26.21 + 4.11y and 40.69 + 9.07y respectively. No differences were shown between groups for patient characteristics. Regarding PGT-A cycle no differences were seen between the number of oocytes and MII retrieved. However, the mean number of biopsied embryos per patient (5.36 + 2.50 vs 3.47 + 1.36; p &amp;lt; 0.05) as well as the percentage of embryos biopsied on day 5 (85.33 vs 32.69; p &amp;lt; 0.05) were higher in the control group. Finally, as expected, the percentage of aneuploidies was higher in the study group (18.64 vs 71.89; p &amp;lt; 0.05). 45 variants were identified in genes potentially associated to the mechanism related to the phenotype. After the variant filtering six probably pathogenic variants were identified. The variants found in the genes were: c.1397T&amp;gt;C (TLE6), c.169G&amp;gt;A (IKBKG), c.1227A&amp;gt;C (BUB1B), c.277G&amp;gt;A (TP73), c.190C&amp;gt;T (PLXNA3) and c.744C&amp;gt;G (AURKC). All variants were heterozygous and all of them were of maternal origin. The females carrying the candidate variants belonged to the study group, and two variants in different genes were identified in one patient. No potentially pathogenic variants were detected in patients from the control group. Therefore, the average detection rate of genetic variants with potential impact in embryo aneuploidy was 33.33% (5/15). Limitations, reasons for caution A notable strength of our study is the inclusion of both (male and female) genomic data. On the other hand, our study has certain limitations including the inherent challenges of any observational study, also, the pathogenicity of the identified variants should be validated in further functional studies. Wider implications of the findings We described new candidate genes that have never been associated to meiotic embryo aneuploidy and are involved in important biological processes (cell division and chromosome segregation). WES may be considered as an efficient tool to identify patients with higher risk of embryo aneuploidy allowing an individualized genetic counselling in advance. Trial registration number Not applicable

Correlation study of male semen parameters and embryo aneuploidy in preimplantation genetic testing for aneuploidy.

The purpose of this study was to evaluate the influence of abnormal semen parameters on embryo aneuploidy based on single nucleotide polymorphism microarray (SNP array). A total of 464 blastocysts from 103 PGT-A cycles were analyzed. The embryo quality and embryo aneuploidy rates were compared between different groups which divided by male semen parameters (sperm concentration, motility, morphology, and DFI) according the WHO criteria (2021). The total blastocysts chromosome aneuploidy rate was 42.3% (191/452). In the teratozoospermia group, the good-quality embryo and blastocyst formation rate were lower than the normal group(44.4% vs 60.7%, P <0.01; 33.3% vs 43.5%, P<0.05), The good-quality embryo rate in normal DFI group was significantly higher than high-DFI group (59.0% vs 48.4%, P < 0.05). The blastocyst aneuploidy rate in low sperm concentration group, and high DFI group was no differences between with that in normal sperm concentration and DFI group (47.7% vs 37.8% and 44.7% vs 37.8%, P>0.05). The aneuploid rate of blastocyst in teratozoospermic and asthenozoospermia group was significantly higher than that of normal morphology and motility group (50.0% vs 34.0% and 46.7% vs 33.7%, P<0.05). Our study revealed that sperm DFI were positively correlated with blastocyst aneuploidy rate, while sperm motility and sperm morphology rate were negatively correlated with blastocyst aneuploidy rate. Abnormal semen parameters may affect embryo quality and increase the aneuploidy rate of blastocyst chromosomes, suggesting that in clinical practice of assisted reproduction patients with abnormal semen parameters can be treated in advance to improve sperm quality, so as to reduce the impact on embryo quality and achieve a better pregnancy outcome.

Can a sperm selection technique improve embryo ploidy?

Spermatozoa with the highest motility retain a superior genomic integrity, and elevated sperm chromatin fragmentation (SCF) has been linked to a lower ability of the conceptus to develop and implant. Therefore, the utilization of a sperm selection method, such as microfluidic sperm selection (MFSS), is capable of reducing the SCF by yielding the most motile fraction of spermatozoa with the highest embryo developmental competence. What remains unclear, however, is the causal mechanism that linksSCF to an impaired embryo development. To identify a relationship between SCF and an unexpectedly high proportion of embryo aneuploidy, while addressing treatment options. We identified couples with a high incidence of embryo aneuploidy in a previous intracytoplasmic sperm injection (ICSI) cycle with pre-implantation genetic testing for aneuploidy (PGT-A), utilizing spermatozoa selected by density gradient (DG). Terminal deoxynucleotidyl dUTP transferase nick-end labeling (TUNEL) and neutral Comet assays were carried out on the semen specimens to assess total SCF and double-stranded DNA (dsDNA) fragmentation, respectively. These couples underwent subsequent ICSI/PGT-A cycles with MFSS. Total SCF and dsDNA fragmentation were compared between the two sperm selection methods. Embryo aneuploidy, implantation, clinical pregnancy, delivery,and pregnancy loss rates were compared between the couples' historical DG and subsequent MFSS cycles. In 57 couples undergoing 71 ICSI/PGT-A cycles, where DG sperm selection was carried out, a high incidence of aneuploid embryos (74.7%) resulted in poor implantation and no viable pregnancies. Testing for SCF, inclusive of dsDNA breaks, evidenced a SCF of 26.2% and dsDNA break of 3.6% in the raw specimen, that decreased to 18.0% (p < 0.001) and 3.1%, respectively, in the DG processed specimen. Following MFSS, total SCF and dsDNA fragmentation decreased to 1.9% and 0.3%, respectively (p<0.001). The embryo euploidy rate remarkable improved from 25.3% in the DG cycles to 42.9% in the MFSS cycles (p<0.001). The 6.7% implantation rate in the DG cycles increased to 65.5% in the MFSS cycles (p<0.001). Similarly, the clinical pregnancy rate rose from 10.5% (DG) to 64.6% (MFSS), resulting in a 62.5% delivery rate (p<0.001). In couples with a relatively young female partner with a negative infertility workup, and a male partner with semen parameters adequate for ICSI, presenting with a high rate of embryo aneuploidy, an additional subtle male factor component may be the culprit. Thus, it is crucial to assess the SCF and test for the dsDNA breaks, which can eventually contribute to embryo chromosomal abnormalities. Given the inverse relationship between SCF and motility, a selection of the most motile gamete by MFSS enhanced the proportion of spermatozoa with an intact genome, contributing to the generation of moreeuploid embryos that are capable of implanting and yielding increased term pregnancies.

THE EFFECT OF STANDART ICSI AND PICSI ON PGT-A RESULTS DURING IVF CYCLES

There is insufficient evidence about the effect of HA sperm selection method for ICSI (PICSI) on embryo aneuploidy rates. Therefore, the aim of this study to compare two sperm selection protocols (Standart ICSI vs. PICSI) on embryo aneuploidy rates, clinical pregnancy and live birth rates based on PGT-A results.

A diagnosis of diminished ovarian reserve does not impact embryo aneuploidy or live birth rates compared to patients with normal ovarian reserve

To estimate the aneuploidy rates in young women with diminished ovarian reserve (DOR) before treatment and poor ovarian response (POR) postretrieval. Retrospective cohort study. A single academically-affiliated fertility clinic. Autologous frozen embryo transfer cycles from December 2014 to June 2020 were reviewed. Demographic and clinical factors that impact outcomes were used for propensity score matching (PSM) in a ratio of 2:1 and 4:1 for preimplantation genetic testing for aneuploidy pre-cycle DOR and POR after stimulation, respectively. None. Aneuploid rates, defined as the number of aneuploid blastocysts divided by the number of biopsied blastocysts per cycle. No euploid embryos to transfer, defined as all cohorts of embryos being aneuploid. A total of 383 women diagnosed with DOR were compared with matched controls. Aneuploid rates did not differ significantly between the two groups (42.2% vs. 41.7%; RR = 1.06; 95% CI, 0.95-1.06). No differences were identified in live birth rates per transfer between women with and without DOR after euploid single-embryo transfers (56.0% and 60.5%, respectively). An additional PSM analysis to assess aneuploidy rates for patients with POR (<5 oocytes) vs. those without it, resulted in similar rates of aneuploidy between the two comparison groups (41.1% vs. 44%, R = 1.02; 95% CI, 0.91-1.14). The prevalence of cycles with "no euploid embryos" in the POR cohort was higher (26% vs. 13%); however, rates of cases with a single embryo available for biopsy were lower in the DOR group, relative to controls (11% vs. 31%). Young women diagnosed with DOR or POR exhibited equivalent aneuploidy rates and live birth rates per euploid embryo transfer in a large matched population, based on age, body mass index, and IVF cycle initiation. The lower percentage of cycles with no euploid embryo available for transfer in DOR and POR patients is because of the decreased total number of oocytes/developing embryos and not because of increased aneuploidy rates in these groups.

P-628 Do ovarian reserve markers and female age predict the rate of euploid blastocysts in IVF/ICSI cycles?

Abstract Study question Are female age and ovarian reserve markers (anti-Mullerian hormone (AMH) and Antral Follicle Count (AFC)), able to predict euploid blastocyst rate in IVF/ICSI cycles? Summary answer Female age, serum AMH, AFC and the number of mature oocytes collected during IVF/ICSI cycles significantly affect the rate of euploid blastocysts What is known already The age-associated decline in female reproduction has been clearly demonstrated, due to the reduction of the ovarian reserve and the increased risk of chromosomal abnormality occurring in the oocyte. Lately, it has been debated whether a reduced ovarian reserve, independently of age, could be associated with higher aneuploidy rate in embryos. Ovarian reserve can now be accurately measured by serum AMH levels and AFC, both markers with similar high reliability. Study design, size, duration This analysis includes data from 10556 blastocysts after preimplantation genetic testing for aneuploidy (PGT-A) with Next Generation Sequencing (NGS). Embryos were obtained from 2564 IVF/ICSI cycles of infertile couples, at ART Fertility Clinics UAE, from November 2016 to December 2020. Participants/materials, setting, methods 10556 blastocysts with chromosomal information for ploidy were included, mosaic and non-informative embryos were excluded. Trophectoderm biopsy was performed on day 5, 6 or 7 blastocysts. Serum AMH concentrations were measured by Elecsys® AMH automated assay (Cobas 601 platform, Roche®) for all patients in a single laboratory. AFC (sum of small antral follicles in both ovaries) was evaluated with transvaginal 2D-sonography (Voluson E8, GE Healthcare). Ethical approval was obtained from the Research Ethics Committee (REFA023b). Main results and the role of chance Patients’ characteristics are described as mean ± SD (min-max): age: 34.72±6.13(18-50), years of infertility: 3.43±3.43(0-25), AMH: 2.52±2.70ng/mL(0.01-23.00), AFC: 11.57±7.86(0-61), body mass index (BMI): 28.57±4.83Kg/m2(14.34-44.96), Metaphase II (MII) inseminated oocytes: 10.11±6.53(1-50), 2PN embryos 7.32±5.12(1-42), blastocysts 4.12±3.21(1-26). Fertilization rate was 73.31%(±19.30), blastulation rate 61.05%(±25.69) and euploidy rate 39.42%(±35.24). A significant negative Pearson correlation coefficient was found between age and euploidy rate (ρ=-0.5398, p &amp;lt; 0.001). AMH, AFC and total of MII inseminated oocytes showed a significant positive Pearson correlation coefficient with euploid rate (AMH:ρ=0.2076, p &amp;lt; 0.001; AFC: ρ = 0.2578, p &amp;lt; 0.001; MII:ρ=0.2036, p &amp;lt; 0.001). Linear regression analysis was conducted to evaluate the predictability of the variables on euploid rate. As expected, age clearly had a negative impact (Coef=-3.10, Std. Err=0.10, p &amp;lt; 0.0001). A positive effect was observed for AMH (Coef=2.75, Std. Err=0.31, p &amp;lt; 0.0001), AFC (Coef=1.16, Std. Err=0.09, p &amp;lt; 0.0001), number of MII inseminated oocytes (Coef=1.10, Std. Err=0.10, p &amp;lt; 0.0001) and 2PN embryos (Coef=1.43, Std. Err=0.13, p &amp;lt; 0.0001). For patients &amp;gt;35 years old and AMH lower than 1.3 ng/mL, euploid rate was significantly lower compared with the patients &amp;gt;35 years old and AMH equal or higher than 1.3 ng/mL (21.2% vs 25.5%, p = 0.0192). Limitations, reasons for caution Despite the large number of cycles and embryos included, the retrospective study design is a limitation. Wider implications of the findings Ovarian reserve is not only a quantitative, but also a qualitative biomarker of oocyte-embryo competence. Cumulative success rates for IVF/ICSI cycles are dependent on the availability of euploid blastocysts. Age and ovarian reserve markers should be combined for adequate counselling. Trial registration number Not applicable

Chromosome aneuploidy analysis in embryos derived from in vivo and in vitro matured human oocytes

BackgroundIn vitro oocyte maturation (IVM) is being increasingly approached in assisted reproductive technology (ART). This study aimed to evaluate the quality of embryos generated by in-vitro matured immature follicles, as a guideline for further clinical decision-making.MethodsA total of 52 couples with normal karyotypes underwent in vitro fertilization, and 162 embryos were donated for genetic screening. Embryos in IVF group were generated by mature follicles retrieved during gonadotrophin-stimulated in vitro fertilization (IVF) cycles. And embryos in IVM group were fertilized from IVM immature oocytes.ResultsThe average age of the women was 30.50 ± 4.55 years (range 21–42 years) with 87 embryos from IVF group and 75 embryos from IVM group. The rate of aneuploid with 28 of the 87 (32.2%) embryos from IVF group and 21 of the 75 (28%) embryos from IVM group, with no significant difference. The frequency of aneuploid embryos was lowest in the youngest age and increased gradually with women’s age, whether in IVF group or IVM group and risen significantly over 35 years old. The embryos with morphological grade 1 have the lowest aneuploidy frequency (16.6%), and increase by the grade, especially in IVF group. In grade 3, embryos in IVM group were more likely to be euploid than IVF group (60% vs 40%, respectively).ConclusionsIVM does not affect the quality of embryos and does not increase the aneuploidy rate of embryos. It is clinically recommended that women more than 35 years have a high aneuploidy rate and recommended to test by PGS (strongly recommended to screened by PGS for women more than 40 years). Women aged less than 35 years old for PGS according to their physical and economic conditions. Embryo with poor quality is also recommended to test by PGS, especially for grade III embryos.

THE INCIDENCE OF COMPLEX CHROMOSOMAL ABNORMALITY (CCA) IN HUMAN EMBRYOS IS AGE-DEPENDENT AND FOLLOWS A U-CURVE OVER FEMALE REPRODUCTIVE AGE

It is well known that the embryo aneuploidy rate increases with women’s age [1], but the effect of age on complex chromosomal abnormality (CCA) is less clear. Here, we addressed the relationship between maternal age and CCA with a retrospective cohort study.

P–262 Comparison of embryo aneuploidy rate and reproductive outcomes of ART cycles using fresh and vitrified donor oocytes

Abstract Study question Is there any difference in blastocyst morphology, embryo aneuploidy rate and ART clinical outcomes when using fresh or vitrified donor oocytes? Summary answer Frequency of good quality blastocyst obtained from fresh oocytes is significantly higher compared to vitrified.No difference in embryo aneuploidy rates nor clinical outcomes were found. What is known already Oocytes vitrification is an efficient method that allows non only fertility preservation but also the creation of donor oocytes banks, optimizing clinical resources for patients undergoing Assisted Reproductive Technology. Although the benefits of donor oocytes vitrification are well known, some studies have shown that this cryopreservation process can induce spindle abnormalities and chromosomal changes, leading to aneuploidy. Comparative studies between fresh and vitrified oocytes to evaluate embryo developmental competence, aneuploidy and clinical pregnancy rate (CPR) are needed. Study design, size, duration This retrospective study includes ICSI cycles with fresh donor oocytes(N = 2795) and vitrified donor oocytes (N = 1225) between January 2019 and September 2020. Pre-implantation Genetic Testing for Aneuploidy (PGT-A) was performed on Day 5 and Day 6 blastocysts. Fertilization rate, blastocyst morphology, aneuploidy status and CPR were analysed and compared between the groups. Recipients were equally distributed in terms of maternal age (40.86 years) and previous history, sperm samples were also similar in profile and origin (fresh-frozen). Participants/materials, setting, methods A total of 266 subfertile couples participated in the study, ICSI was carried out in all cycles. Vitrification and warming protocols were performed with a commercial kit. All embryos were cultured to blastocyst stage in a Time-Lapse incubator and assessed by Gardner’s blastocyst grading scale. PGT-A testing was performed on trophectoderm biopsies by Next Generation Sequencing (NGS). Single/double embryo transfers were performed in all cases. Odd-ratios were calculated,and Chi-square was performed for the statistical analysis. Main results and the role of chance A total of 266 patients underwent 289 donor oocyte cycles yielding an overall of 4557 oocytes. ICSI was performed on 2795 fresh and 1225 vitrified mature oocytes. Similar fertilization rates were achieved with fresh and vitrified oocytes (75.9% (2122/2795) and 75.2% (921/1225), respectively (P = 0.6)) yielding a significant difference in blastocyst rate of 71.7% (1522/2122) and 62.5% (576/921) (OR 1,519; 95% CI 1,290–1,789; p &amp;lt; 0.001). In addition, when blastocysts morphology was analysed, a significant difference was shown in the frequency of good quality embryos that decreases from 56.6% (861/1522) with fresh oocytes to 51% (294/576) with vitrified oocytes (OR 1,249; 95% CI 1,031–1,514; P &amp;lt; 0.02). PGT-A testing of blastocysts revealed not significant differences in euploidy rates (73.6% in fresh oocytes vs 76.8% vitrified oocytes, P = 0.2). With regards to clinical outcomes, similar results were found between the groups. A total of 322 embryo transfers were performed (237 from fresh and 85 vitrified) achieving a CPR of 48.9% (116/237) with fresh oocytes and 54% (46/85) with vitrified (P = 0.7) and a pregnancy loss of 6.7%(16/237) in fresh oocytes and 11.7%(10/85) vitrified oocytes (P = 0.1). Limitations, reasons for caution The study was conducted on a small number of cases. Further studies are needed to confirm our findings. Moreover, although the same stimulation protocol was used, donors from different background were included. Wider implications of the findings: This study supports the use of vitrified oocytes in the laboratory routine without compromising clinical outcomes. Although oocyte vitrification may have an influence on embryo morphology, blastocyst rate, no impact of this cryopreservation process is seen on embryo aneuploidy, developmental competence and CPR. Trial registration number Not applicable

P–005 Magnetic-activated cell sorting in couples undergoing preimplantation genetic testing for aneuploidies (PGT-A) using autologous oocytes shows slightly lower aneuploidy rates compared to standard semen processing

Abstract Study question Does the selection of non-apoptotic sperm via magnetic-activated cell sorting (MACS) reduce the aneuploidy rate of embryos from couples undergoing ICSI cycles with PGT-A using the patients’ own oocytes? Summary answer It does. The aneuploidy rate in the MACS group was 4.34% lower than the one obtained using semen samples processed according to standard clinical practice. What is known already MACS is a successful tool in eliminating proapoptotic sperm from a semen sample. However, the true effect of this technique on reproductive outcomes and the quality of the resulting embryos are a matter of controversy. Some studies report that its use improves the percentage of good quality blastocysts in women older than 30 years old compared to standard ICSI. Randomized clinical trials that compare MACS to a control sample consider parameters of embryo quality such as morphology at day 3 or day 5, symmetry of the blastomeres, blastocysts’ stage of expansion, but they do not consider embryo ploidy. Study design, size, duration Retrospective, multicentre, observational cohort study. 14,145 patients and 18,710 cycles were evaluated in the reference group. In the MACS group, 615 patients and 974 cycles were considered. Data were exported from cycles performed in Spanish IVIRMA clinics between January 2008 and February 2020. Participants/materials, setting, methods Unselected males in couples undergoing PGT-A cycles, then subdivided into male factor (MF) - total progressive motile sperm count lower than 5 million - and non-male factor (NMF) infertility. Statistical analysis performed using R v.4.0.0. Means were calculated and compared using two-tailed paired t-test, while proportions were compared using Fisher’s exact test and the chi-squared test and the appropriate correction for multiple comparisons. The aneuploidy rates for each group were compared using Fisher’s exact test. Main results and the role of chance In the control group 73,228 biopsied embryos, from which 71,439 were informative in the PGT-A. In the MACS group 3,919 biopsied embryos, from which 3,843 were informative. The aneuploidy rate, computed per informative embryo, was 68.87% (68.40%, 69.34%) in the reference group and 64.53% (62.43%, 66.64%) in the MACS group. Both comparisons were statistically significant (p-value ˂0.00001). According to these results, an embryo in the PGT-A programme using non-apoptotic sperm selected through MACS and autologous oocytes had a 5% less chance of being aneuploid than those embryos fertilised with standardly selected sperm (relative risk of 0.95 (0.91–0.98) p = 0.006769). Embryos conceived from NMF patients whose semen had been processed using MACS had a 4.27% lower aneuploidy rate than the reference (65.52% (63.16%, 67.88%) vs 69.79% (69.20%, 70.37%) respectively). This difference was statistically significant. Those embryos conceived using semen from patients with MF using MACS also showed a lower aneuploidy rate than the reference with MF (0.28% (55.48%, 65.08%) vs (64.94% (63.35%, 66.23%) respectively), although this difference was not statistically significant. Thus, the decrease in aneuploidy rate observed when comparing MACS and reference groups undergoing PGT-A cycles using autologous oocytes remained approximately the same in both MF and NMF semen samples. Limitations, reasons for caution The retrospective nature of the study subjects the data to biases or inaccuracies in their annotation in the clinics’ informatic platform from which they were exported. However, the statistical analysis aimed at controlling these biases as much as possible. Wider implications of the findings: The vast amount of data compiled for this study confirms that the selection of non-apoptotic sperm through MACS slightly decreases the aneuploidy rate of embryos compared to semen samples processed according to the clinics’ standards. This would be interesting for patients who are considering undergoing PGT-A cycles in the future. Trial registration number Not applicable

P–551 Blastocyst cohort size is not associated with embryo aneuploidy: comprehensive multi-centre data from current preimplantation genetic testing cycles

Abstract Study question Does blastocyst cohort size impact aneuploidy rates, evaluated by next generation sequencing (NGS)? Summary answer Embryo aneuploidy rates were independent of blastocyst cohort size across all patient ages. What is known already The effects of ovarian response on oocyte and embryo quality remain controversial. Several studies have proposed that a high response to ovarian stimulation may negatively impact oocyte competence. Alternatively, irrespective of maternal age, a poor ovarian response may potentially compromise embryo quality. Using blastocyst cohort size as an indirect measure of ovarian response, previous studies applying array comparative genomic hybridisation (aCGH) have demonstrated that the number of embryos available for biopsy does not impact embryo aneuploidy rates. Nevertheless, these findings remain to be confirmed in a comprehensive cohort, using current approaches for preimplantation genetic testing for aneuploidies (PGT-A). Study design, size, duration Retrospective, international, cohort study of 3998 patients from 16 clinics undergoing PGT-A from 2016–2020. We evaluated 11665 blastocysts, tested using trophectoderm (TE) biopsy and next generation sequencing (NGS). To eliminate bias of multiple treatments, we considered only the first PGT-A cycle for all patients. Both autologous and donation cycles were included in the analysis. Cycles were excluded if they utilised preimplantation genetic testing for monogenic disorders (PGT-M) or preimplantation genetic testing for structural rearrangements (PGT-SR). Participants/materials, setting, methods We evaluated aneuploidy and mosaicism rates, as well as the proportion of patients who had at least one euploid embryo suitable for transfer. Findings were stratified according to SART-defined maternal age groups, &amp;lt;35 (n = 698/2622 patients/blastocysts), 35–37 (n = 988/3141 patients/blastoycsts), 38–40 (n = 1447/3939 patients/blastocysts), 41–42 (653/1562 patients/blastocysts) and &amp;gt;42 (212/401 patients/blastocysts) and blastoycst cohort size (1–2, 3–5, 6–9 and 10 or more biopsied blastocysts). Main results and the role of chance The mean maternal age was 37.0±3.7. The overall embryo aneuploidy rate was 50.6% (5904/11665), while mosaicism was established in 4.0% (469/11665) of blastocysts. As expected, the proportion of aneuploid embryos increased steadily with advancing maternal age (31.8%, 41.5%, 58.4%, 71.2%, 87.8%; p &amp;lt; 0.0001), while mosaicism rates did not vary significantly (p = 0.2). Within each age group, we observed no association between the number of blastocysts biopsied and aneuploidy or mosaicism rates. However, as previously suggested, the chance of having at least one euploid embryo increased linearly with the number of embryos biopsied. We observed that young patients (&amp;lt;35) with 1–2 blastocysts had a 70.4% of having at least one embryo suitable for transfer, which increased to 96.4% and 99.2% with 3–5 and 6–9 blastocysts, respectively. Similar trends were observed in the 36–38 and 39–40 age groups. Patients in the 40–41 age group had a significantly lower chance of having a suitable embryo for transfer. Nevertheless, the chance increased from 27.2% with 1–2 embryos to 61.2% with 3–5 blastocysts. Patients with &amp;gt;10 embryos had at least one euploid embryo in 100% of cases, across all ages. Albeit, the numbers of patients within this category was low, and decreased significantly with advancing maternal age. Limitations, reasons for caution While blastocyst cohort size is considered to be an indirect measure of ovarian reserve, the number of oocytes retrieved was not evaluated. Our study only included the first PGT-A cycle for all patients. Subsequent, alterations in stimulation protocols may have resulted in an improved response in some patients. Wider implications of the findings: The comprehensive nature of the study, based on current PGT-A approaches and a large number of cycles across 16 centres increases clinical confidence in the notion that ovarian response is independent of embryo aneuploidy. Importantly, our findings may serve as a valuable clinical resource to guide patient counselling strategies. Trial registration number NA

P–066 Does microfluidic sperm sorting (MSS) affect embryo euploidy rates in couples with high sperm DNA fragmentation (SDF)?

Abstract Study question Does MSS (microfluid chip-sorted spermatozoa selection) provide improvement on embryo quality and euploidy rates in couples with high SDF (sperm DNA fragmentation) and previous failed in vitro fertilization/ intracystoplasmic sperm injection (IVF/ICSI) cycles? Summary answer Use of MSS technique provides higher number of top quality blastocysts compared to density gradient centrifugation (DGC), however euploidy and live birth rates weren’t improved. What is known already Previously it has been reported that sperm DNA damage leads to poor embryo development and there is a significant association between SDF and high embryo aneuploidy rates. Recently this fact raised attention to sperm selection techniques such as MSS to enhance embryo quality, miscarriage rates and embryonic euploidy rates. Study design, size, duration This was a retrospective electronic medical record (EMR) analysis of a tertiary assisted reproduction center between 2016 and 2020. All EMR were reviewed to select eligible cases as; couples undergoing a new IVF/ICSI cycle with PGT-A (preimplantation genetic testing for aneuploidies). In total, data from 243 patients were obtained for the analysis that accounts for 688 embryos. Participants/materials, setting, methods Patients had at least 2 previous failed IVF cycles and males had at least 20% SDF. In their new cycles, MSS was offered, preceding ICSI and PGT-A. Couples who accepted the technique were assigned to MSS group (92 cycles with 310 embryos) and the rest were managed with DGC and assigned as controls (151 cycles with 378 embryos). Azoospermia cases and women with age&amp;gt;43, uterine abnormalities, trombophilia were excluded. Biopsies were performed at blastocyst stage. Main results and the role of chance Two groups were comparable in terms of demographic data including women and men age, SDF, sperm parameters and cycle characteristics. There was no difference between groups in terms of fertilization rates (MSS 85% vs DGC 79% p = 0.9), euploidy rates (MSS 53.2% vs DGC 50.7% p = 0.3), mean no of euploid embryo per patient (MSS 1.09 vs DGC 0.95 p = 0.3), positive pregnancy test (MSS 50% vs DGC 38.4% p = 0.06), clinical miscarriage (MSS 7.6% vs DGC 6.6% p = 0.7) and live birth rates (LBR)(MSS 42.4% vs DGC 31.7% p = 0.09). Total no of blastocysts and top quality blastocysts were significantly higher in MSS group than in DGC (3.9 vs 2.5 p &amp;lt; 0.01 and 1.6 vs 0.8 p &amp;lt; 0.001 respectively). Limitations, reasons for caution Retrospective design, small sample size, lack of proper randomization and power analysis are the main limitations. Wider implications of the findings: Offering PGT-A to couples with unexplained repeated IVF failures and high SDF seems feasible. MSS for such cases improves embryonic division process as improved blastulation rates were documented. However, euploidy rates were not improved in MSS group revealing that other factors influence comprehensive chromosomal status of an embryo. Trial registration number Not applicable

Methylenetetrahydrofolate reductase gene polymorphisms are not associated with embryo chromosomal abnormalities and IVF outcomes

ABSTRACT The aim of our study was to investigate the effect of maternal and embryo MTHFR C677T and A1298C polymorphisms on embryo aneuploidies and mosaicism and the correlation between these genetic variants in transferred euploid embryos and IVF outcomes. MTHFR genotype was analyzed in 77 women who performed an IVF/ICSI cycle with PGT-A. Moreover, to evaluate the effect of embryo MTHFR polymorphisms on embryo aneuploidies and mosaicism, the MTHFR genotype was analyzed in 191 biopsied embryos from the PGT-A cycles of these patients. Additionally, 218 DNA samples from trophectoderm biopsies belonging to a different group of patients were also genotyped. MTHFR polymorphisms were analyzed in a total amount of 409 trophectoderm samples. The main parameters analyzed were embryo aneuploidy and mosaicism rates. Finally, the IVF outcomes of 241 single euploid embryo transfers were assessed and compared between different MTHFR embryo genotypes. The aneuploidy rates were similar in embryos from homozygous normal women and women with at least one mutated allele (54.7% vs. 30.2% in 677C>T and 37.8% vs. 42.7% in 1298A>C). Furthermore, no differences were observed in the mosaicism rate (24.0% vs. 13.8% in 677C>T and 17.1% vs. 17.3% in 1298A>C). A similar analysis was performed, taking into account the embryo genotype results. No differences in aneuploidy rate were observed between the study groups. The only significant difference was the mosaicism rate among 677C>T genotype (13.5% in 677CC group vs. 5.4% in 677CT/TT; p = 0.019). Implantation rate, biochemical and clinical miscarriage rates, and ongoing pregnancy rate were compared between different embryo genotypes, and no statistically significant differences were found. In conclusion, the maternal MTHFR genotype did not influence embryo chromosomal abnormalities. Moreover, the embryo MTHFR genotype was not associated with embryo aneuploidy or IVF outcomes such as implantation, pregnancy loss, and ongoing pregnancy when euploid embryos were transferred. Abbreviations: MTHFR: methylenetetrahydrofolate reductase; IVF: in vitro fertilization; PGT-A: preimplantation genetic testing for aneuploidies; SAM: S-adenosyl methionine; SNP: single nucleotide polymorphism; SPSS: Statistical Package for Social Sciences; RIF: recurrent implantation failure; RPL: recurrent pregnancy loss; hCG: human chorionic gonadotropin; PBS: phosphate buffered saline; CGH: comparative genomic hybridization; NGS: next generation sequencing

Effect of ovarian stimulation on embryo aneuploidy and mosaicism rate

ABSTRACT There is a high incidence of chromosome abnormalities in human embryos that leads to a failed IVF cycle. Different studies have shown that maternal age is the determining factor in the appearance of chromosomal alterations in the embryo. However, the possible influence of ovarian stimulation on oocyte and embryo aneuploidies and mosaicism is controversial. A retrospective study was carried out in which 835 embryos from 280 couples undergoing reproductive treatment using their oocytes were chromosomally analyzed. A binary logistic regression analysis was performed to evaluate the relationship between different parameters characterizing controlled ovarian stimulation (COS) and the rate of aneuploidy and embryonic mosaicism. The embryo aneuploidy rate showed no association with the use of oral contraceptives, type, total and daily doses of gonadotropins, stimulation protocol type, and drugs used for ovulation trigger (p > 0.05). In contrast, the duration of the ovarian stimulation treatment was correlated with the aneuploidy rate: patients requiring more days of stimulation presented a lower rate of aneuploid embryos (p = 0.015). None of the variables studied showed any association with the rate of embryo mosaicism. However, the duration of COS showed association with the appearance of aneuploidy, suggesting that faster recruitment could be deleterious for those reassuming meiosis, yielding more abnormal karyotype. Abbreviations: IVF: in vitro fertilization; COS: controlled ovarian stimulation; PGT-A: preimplantation genetic test for aneuploidy; hCG: human chorionic gonadotropin; GnRH: gonadotropin-releasing hormone; LH: luteinizing hormone; FSH: follicle-stimulating hormone; NGS: next-generation sequencing; a-CGH: comparative genomic hybridization; TUNEL: Terminal transferase dUTP Nick End Labeling; FISH: fluorescent in situ hybridization