The effect of daily ejaculation on semen parameters and sperm DNA damage in normal men

Abstract

Poor semen quality and sperm DNA damage have been associated with deleterious effects on male reproductive potential, including decreased fertility rates and increased rates of miscarriage. Although increased days of abstinence may have a negative effect on semen quality, the effects of increased frequency of ejaculation on semen quality have not been extensively studied. Here we assessed the effects of 14 days of daily ejaculation on standard semen parameters and sperm DNA damage in normal men. Prospective study with subject as his own control. Nineteen healthy men, without history of smoking or infertility and mean age 25, underwent daily ejaculations for 14 consecutive days after a 3-5 day abstinence period. Semen samples were collected on Days 1, 3, 7 and 14. Standard semen parameters were assessed as well as: 1) DNA fragmentation index (DFI) and high DNA stainability (HDS) using flow cytometry/acridine orange (SDFA) test, and 2) reactive oxygen species damage, oxidative stress adduct (OSA) test. To date, complete data on 11/19 men were obtained. All 11 men began the study with normal standard semen parameters. Semen volume for all time points and total motile count for days 3 and 14 decreased with respect to day 1 (P<0.05). No significant changes were observed in other parameters including: motility, DFI, HDS, and OSA. Two of the 3 men with DFI's above 15%, showed 30% and 50% reduction (improvement) in DFI by day 14. This study represents one of the most extensive examinations of parameters of semen health with daily ejaculation in normal men. Daily ejaculation for up to 14 days produced expected reductions in semen volume and total motile concentration but did not result in significant worsening of parameters of semen health including percent motility, DNA integrity, immature sperm, and end damage from reactive oxygen species. Future studies will focus on oligospermic men with sperm with high DNA damage which may be improved by more frequent ejaculation.