Sperm H3K9me3 levels are associated with embryo developmental dynamics and biochemical pregnancy in IVF patients with normozoospermia

This study reveals that sperm H3K9me3 levels vary among normozoospermic men and correlate with early embryo development and biochemical pregnancy rates following IVF. However, no significant association was found with ongoing pregnancy, suggesting that additional mechanisms may determine long-term pregnancy viability. The non-linear relationship between H3K9me3/H3 ratio and embryo development suggests an optimal range for this epigenetic mark. These findings highlight the potential influence of paternal epigenetic variation, undetectable by standard semen analysis, on embryo quality and IVF outcomes. Further studies in larger cohorts are warranted to confirm these findings and clarify underlying mechanisms.