Correlation of DNA fragments with routine semen parameters and lifestyle and their impact on assisted reproductive outcomes.

Objective: This study investigated the correlation between sperm DNA integrity and routine semen evaluation parameters in male infertile patients, the influencing factors, and the impact of the DNA fragmentation index (DFI) on embryo quality and clinical outcomes in in vitro fertilization and embryo transfer (IVF-ET).

Methods: Sperm DFI and semen routine parameters of 6160 infertile men admitted between June 2017 and June 2018 were analyzed. Patients were divided into three groups according to their DFI: low-DFI (DFI<15%), medium-DFI (15%30%). The correlations of DFI with patients' age, sperm concentration, sperm percentage of forward movement and sperm percentage of normal shape were analyzed. The clinical data of 5040 infertile couples who received IVF treatment between June 2016 and 2021 and had embryos transferred in a fresh cycle were reviewed. The fertilization rate, cleavage rate, blastocyst rate, and pregnancy rate in different DFI groups were compared.

Results: Semen evaluation parameters (concentration, spermatozoa with progressive motility, and the normal morphology rate), the high-quality embryo rate, blastocyst development rate, and pregnancy rate in the high-DFI group were significantly lower than those in the other two groups. The correlation analysis revealed that sperm DFI was negatively correlated with semen concentration, sperm motility, and normal sperm morphology and positively correlated with the man's age, BMI, and unhealthy habits (smoking and drinking). There was no significant difference in the number of mature eggs and normal fertilization rate among groups.

Conclusion: A strong correlation exists between sperm DFI and semen evaluation parameters. Smoking, drinking, and other unhealthy habits lead to an increase in DFI, reducing the high-quality embryo rate and blastocyst development rate and affecting pregnancy outcomes.