Analysis of semen parameters during 2 weeks of daily ejaculation: a first in humans study

BACKGROUND Timed and frequent intercourse around the time of female ovulation is recommended to improve conception. Although a significant number of articles have examined how the length of abstinence affects these semen analysis, the effects of frequent (daily) ejaculation has not been rigorously studied. METHODS Twenty normal men were recruited for daily ejaculation over 14 consecutive days, after a 3-5 days abstinence period. Semen samples were collected at the beginning of the study (day 1) and then on days 3, 7 and 14. In addition to the standard semen analysis, markers of sperm DNA quality were assessed. RESULTS The mean age of men completing the study was 25 years (range, 23-33 years). Significant decreases were observed in mean semen volume, total motile count (TMC) and sperm concentration during the study period without significant changes in motility or morphology. A large initial change in ejaculate volume, TMC and sperm concentration provided the primary difference in these values over the study period, with a plateau in values after this initial decrease (after study day 3). Metrics of DNA integrity did not change in a statistically or clinically meaningful way during the study period. CONCLUSIONS While a small study, this represents the most extensive examination of sperm quality with daily ejaculation. These findings generally support an approach of a short period of abstinence followed by daily copulation around ovulation to maximize the number of sperm available and optimize conception.