Improved sperm DNA fragmentation levels in infertile men following very short abstinence of 3-4 hours

Background: Limited data exists on possible approaches to improve sperm DNA fragmentation index (DFI) when no identifiable cause is found. The effect of short abstinence on sperm parameters has been extensively studied, but rarely reported on the effect on DFI in infertile men. In this study, we aimed to determine whether a second ejaculate provided after very short abstinence demonstrates lower DFI rates in infertile men.Methods: This prospective cohort study was conducted at Mount Sinai Hospital, Toronto, Canada, a tertiary university affiliated hospital. All men having DFI testing in addition to the standard semen analysis were identified via a prospectively collected database. Infertile men were instructed to provide two semen samples 3-4 hours apart (the first sample was given after 2-5 days of abstinence) to test the effect on DFI levels. Data analysis was performed for the comparison of the change in sperm parameters and DFI between samples and between men with DFI above and under 30%.Results: A total of 52 men provided double ejaculates 3-4 hours apart. In the entire group, DFI decreased from 38.9%+/- 21.4% to 35.1%+/- 21.6% in the second sample (P<0.001). Semen volume was lower on the second sample (2.3 +/- 1.4 vs. 1.5 +/- 0.9 mL, P<0.001), while the remaining parameters did not change. Forty out of 52 patients (76.9%) had improved DFI (average of 6.0 +/- 4.0 percentage points). Change in DFI varied with 22/52 (42.3%) and 7/52 (13.5%) of patients found to have decreases in DFI >5% and >10% in the second ejaculate, respectively. For men with DFI of 30-40%, 64% (7/11) of DFIs reduced to the under 30% range. First DFI value was the only parameter associated with DFI decrease to under 30% in multivariate models [odds ratio (OR), 0.62; 95% confidence interval (CI): 0.39-0.98; P=0.04].Conclusions: This study identified significant improvements in DFI in infertile men providing a second sample after 3-4 hours. Controlled trials are needed to determine if reproductive outcomes are improved using a second ejaculate for infertile men with high initial sperm DFI values.