Sperm SCSA DNA fragmentation index does not influence the euploidy rate of viable blastocysts in advanced-age women

Oocytes from older females have a diminished ability to repair sperm DNA damage compared with those from younger females. Previous research has indicated that there is no significant correlation between sperm DNA fragmentation index (DFI) and the blastocyst euploidy rate in cycles utilizing oocytes donated by young individuals. However, it is still unclear whether a high DFI impacts the euploidy rate of blastocysts derived from oocytes obtained from women of advanced reproductive age.

The aim of this study was to investigate the potential association between sperm DFI and the euploidy rate of viable blastocysts in women of advanced age undergoing preimplantation genetic testing for aneuploidy (PGT-A).

A total of 667 blastocysts from 492 couples, all with maternal ages of 38 years or older, who underwent intracytoplasmic sperm injection (ICSI) combined with PGT-A were included in this study. The sperm DFI values were measured using the Sperm Chromatin Structure Assay (SCSA), and the couples were divided into three groups based on sperm DFI values: low DFI (DFI < 15%), moderate DFI (15% ≤ DFI ≤ 30%), and high DFI (DFI > 30%).

No statistically significant differences were found in the rates of normal fertilization among the low, moderate, and high DFI groups (73.3%, 75.8%, and 75.4%, respectively; p > 0.05). Similarly, the rates of high-quality embryos were comparable among the groups (47.2%, 45.5%, and 45.7%, respectively; p > 0.05). The blastocyst formation rates also exhibited no significant differences among the groups (49.9%, 48.0%, and 49.3%, respectively; p > 0.05). Additionally, the aneuploidy rates of viable blastocysts were comparable across the groups (55.1%, 59.1%, and 60.6%, respectively; p > 0.05). Both the categorical analysis based on clinical DFI thresholds (<15%, 15%-30%, >30%) and the multiple linear regression treating DFI as a continuous variable (adjusted for female age, female body mass index [BMI], duration of infertility, number of miscarriages, and male age) revealed no statistically significant association between DFI and blastocyst euploidy rates (p = 0.733 for the categorical analysis; B = -0.003, standard error [SE] = 0.002; p = 0.136 for the continuous model). Furthermore, clinical pregnancy outcomes and neonatal results following the transfer of euploid blastocysts were comparable among the groups.

This study's findings suggest that elevated sperm DFI, as measured by the SCSA, does not significantly influence the euploidy rate of viable blastocysts in couples with advanced maternal age, whereas maternal age remains the predominant factor influencing embryo euploidy.