O-216 The impact of maternal age on cumulative life birth rates after single euploid embryo transfer: differences between autologous and donor oocyte cycles

Abstract Study question How much of an impact has the maternal age on cumulative life births after euploid Single Embryo Transfer (SET) in autologous and donor oocyte cycles? Summary answer A maternal age ≥ 42 years old affects negatively the cumulative Life Birth Rates (cLBRs) even after euploid SET, but only in the autologous cycles. What is known already Despite the improvements in assisted reproduction technologies (ART) in the last decades, the LBRs remain suboptimal, especially when advanced maternal age is considered. Although several factors could explain these outcomes (i.e. infertility history; uterine pathologies/surgery; advanced paternal age), maternal age-related aneuploidies remain the most limiting factor for a favorable clinical outcome. Thus, the Genetic Testing for Aneuploidies (PGT-A) has been integrated into ART as a strategy to evaluate chromosomal status before transfer. Interestingly, recent studies show that, even after the transfer of euploid blastocyst, the maternal age negatively influences the LBRs. Study design, size, duration This study, carried out in Villa Mafalda Reproductive Medicine Department (Italy), included 568 euploid SET: 542 from autologous cycles (divided in four subgroups according to maternal age: ≤ 34 y.o. (n = 207); 35-38 y.o. (n = 193); 39-41 y.o. (n = 106); ≥ 42 y.o. (n = 36)) and 26 from oocyte donation (OD) cycles (average recipient age is 44.2). All cycles were performed from May 2020 to February 2023. PGT for Monogenic disorders (PGT-M) cycles were excluded. Participants/materials, setting, methods All blastocysts included in this study were analyzed by Next Generation Sequencing (NGS) after a day 5/6 trophectoderm biopsy. For each subgroup was annotated the embryo morphology- divided into good (AA-AB-BA); average (BB-BC-CB) and poor (CC) according to Gardner/Schoolcraft blastocyst grading system- and the day of expanded blastocyst formation (grade 4 of Gardner/Schoolcraft blastocyst grading system). Primary analysis included the cumulative LBRs. Secondarily, blastocyst morphology and blastocyst expansion were examined for all embryo categories considered. Main results and the role of chance The pairwise comparison between groups was performed by Chi-square analysis and p 0.05 was considered statistically significant. The cLBRs for each subgroup were respectively: ≤ 34 (63.09%); 35-38 (58.47%); 39-41 (56.84%); ≥ 42 (48.57%); OD (69.23%). Data showed that cLBRs decreased with the increase of maternal age, although statistical significance was observed only among women ≤ 34 y.o. and ≥ 42 y.o. (P=0.029). Notably, there was no statistical significance in cLBRs comparing women ≤ 34 y.o. and OD patients (P=0.086). The good-quality blastocyst rate was respectively: ≤ 34 y.o. (54.58%); 35-38 y.o. (47.66%); 39-41 y.o. (60.37%); ≥ 42 y.o. (50%); OD (59.37%). The pairwise comparison showed no significant difference between groups. Furthermore, there was not found significant difference about the day of expanded blastocyst formation: ≤ 34 y.o. (D5: 78.92%; D6 21.07%); 35-38 y.o. (D5: 78.49%; D6: 21.50%); 39-41 y.o. (D5:75.70%;D6: 24.29%); ≥ 42 y.o. (D5:69.44%; D6: 30.55%); OD (D5: 87.5%; D6: 12.5%). Data showed that maternal age ≥ 42 y.o. affects negatively cLBRs even after euploid SET, suggesting that other factors age-related, rather than aneuploidies, influence implantation. Interestingly, these factors do not affect OD recipients, with advanced maternal age, who, instead, reach successful LBRs like patients ≤ 34. Limitations, reasons for caution These results should be evaluated carefully because of the small sample size of the OD patients. A greater number of OD cycles are needed to verify the results obtained. Wider implications of the findings Our findings suggest that embryonic age-related factors - changes in gene expression, metabolism or epigenetics - could influence the embryo capability to, successfully, support implantation other than the ploidy status. This thesis was supported by the OD recipient’s behavior, who had cLBRs comparable to young autologous patients. Trial registration number Not Applicable