[Correlation of sperm DNA fragmentation index with age and semen parameters and its influence on the outcomes of IVF-ET].

Objective: To explore the correlation of the sperm DNA fragmentation index (DFI) with age and other semen parameters in infertile men and its influence on the outcomes of in vitro fertilization and embryo transplantation (IVF-ET).

Methods: Semen samples were obtained from 6 162 infertile males in our hospital between July 2017 and December 2018. Sperm concentration, the percentages of progressively motile sperm (PMS) and morphologically normal sperm (MNS) and sperm DFI were determined by computer-assisted semen analysis, modified Papanicolaou staining and sperm chromatin structure assay, respectively. According to the sperm DFI, the samples were divided into three groups: DFI≤15%, 15%30%. Comparisons were made among different groups in the rates of fertilization, embryo cleavage, embryo formation and pregnancy.

Results: Spearman correlation analysis showed that DFI was correlated positively with age (r = 0.508, P < 0.05), but negatively with sperm concentration (r = －0.155, P < 0.05) and the percentages of PMS (r = －0.111, P < 0.05) and MNS (r = －0.315, P < 0.05). With sperm DFI >20%, the clinical pregnancy rate of IVF-ET was significantly reduced, while with sperm DFI >30%, the rate of available embryos markedly decreased and that of biochemical pregnancy remarkably increased. No correlation was found between sperm DFI and the rates of fertilization, embryo cleavage and high-quality embryos in IVF-ET.

Conclusions: In infertile males, sperm DFI is correlated positively with age but negatively with sperm concentration and the percentages of PMS and MNS, and it significantly affects the outcomes of IVF-ET.