Sperm DNA Fragmentation Impairs Early Embryo Development but Is Not Predictive of Pregnancy Outcomes: Insights from 870 ICSI Cycles

Sperm DNA fragmentation (SDF) is increasingly regarded as a biomarker of male infertility, but its predictive value for intracytoplasmic sperm injection (ICSI) outcomes remains controversial. This retrospective cohort study analyzed 870 fresh single-blastocyst ICSI cycles performed between January 2023 and December 2024. SDF was measured using the Sperm Chromatin Dispersion test and patients were categorized into low (SDF ≤ 20%, <i>n</i> = 664) and high (SDF > 20%, <i>n</i> = 206) groups. Higher SDF was significantly associated with reduced semen quality, lower fertilization rates, and poorer blastocyst development. In multivariable analysis, each 1% increase in SDF reduced the odds of achieving a fertilization rate > 80% by 1.6% (OR = 0.984, 95% CI: 0.971-0.997, <i>p</i> = 0.015) and decreased the chance of obtaining top-quality blastocysts on day 5 by 2.5% (OR = 0.975, 95% CI: 0.958-0.992, <i>p</i> = 0.004). A trend toward impaired day-3 embryo quality was observed (OR = 0.983, <i>p</i> = 0.068). No significant association was found with clinical pregnancy (OR = 0.989, <i>p</i> = 0.155), while the relationship with miscarriage was borderline (OR = 0.961, <i>p</i> = 0.053). These findings suggest that elevated SDF adversely impacts early embryological outcomes in ICSI, supporting its use as a prognostic tool during ART counseling.