Effects of sperm DNA fragmentation on embryo morphokinetic parameters and laboratory outcomes in women of different ages during intracytoplasmic sperm treatment cycles.

Abstract

Background: Whether SDF (sperm DNA fragmentation) influences embryo development and the clinical outcomes of assisted reproductive technology (ART) cycles remains controversial. Oocytes derived from women of different ages have varying abilities to repair SDF.

Objective: This study aimed to explore the correlation between SDF and the morphokinetic parameters of embryos during intracytoplasmic sperm injection (ICSI) treatment cycles with consideration of the different ages of female patients.

Materials and methods: A total of 301 ICSI cycles between April 2022 and December 2023 were analyzed in this retrospective study. Cycles were categorized into two groups according to female age: the older group (females aged ≥ 35 years) and the younger group (females aged < 35 years). Moreover, each age group was further divided into low- and high- sperm DNA fragmentation index (DFI) subgroups. The morphokinetic parameters of embryo development and the laboratory outcomes were compared between the two DFI subgroups within each age category.

Results: In the younger group, there were no differences between the two DFI groups in terms of the rate of usable blastocyst formation on Day 5; time to 2, 3, 4, 5, 6, 7, and 8 cells; or timing of blastulation. However, in the older group, the rate of usable blastocyst formation on Day 5 was significantly greater in the low DFI group than in the high DFI group (35.6% vs. 23.4%, p = 0.030). Although the times to reach 2, 3, 4, 5, 6, 7, and 8 cells were similar across the two DFI groups, the time to blastulation (tB) was significantly shorter in the low DFI group than in the high DFI group (106.5 ± 9.0 h vs. 111.1 ± 10.3 h, p = 0.013).

Conclusion: SDF could adversely affect the rate of usable blastocyst formation on Day 5 and delay the formation of usable blastocysts only when oocytes were derived from women of advanced maternal age. These results may indicate that oocytes derived from younger females have a greater capacity to repair SDF than those from women of advanced maternal age.