1 July 2009
Daily sex boosts male fertility
by Kate Melville
Ejaculating more frequently improves men's sperm quality by reducing the amount of DNA damage and improving sperm motility, Australian researchers reported to the 25th annual meeting of the European Society of Human Reproduction and Embryology in Amsterdam. Until now there has been no evidence-based consensus as to whether or not men should refrain from sex for a few days before attempting to conceive with their partner.
"We didn't know what was the best advice for the period leading up to ovulation or egg retrieval for IVF. I thought that frequent ejaculation might be a physiological mechanism to improve sperm DNA damage, while maintaining semen levels within the normal, fertile range," fertility specialist David Greening told the conference.
To investigate his hypothesis, Greening studied 118 men who had higher than normal sperm DNA damage. The men were instructed to ejaculate daily for seven days and no other treatment or lifestyle changes were suggested. Before they started, levels of DNA damage ranged between 15 - 98 percent, with an average 34 percent DFI (DNA Fragmentation Index) when measured after three days' abstinence.
When the men's sperm was assessed after the week, Greening found that nearly all the men had a decrease in sperm DNA damage. The average DFI for the whole group dropped to 26 percent.
"These changes were substantial and statistically highly significant," noted Greening. "In addition, we found that although frequent ejaculation decreased semen volume and sperm concentrations, it did not compromise sperm motility and, in fact, this rose slightly but significantly. Further research is required to see whether the improvement in these men's sperm quality translates into better pregnancy rates, but previous studies have shown the relationship between sperm DNA damage and pregnancy rates."
Greening added that while the optimal number of days of ejaculation might be more or less than seven days, a week appeared to be manageable. "It seems safe to conclude that couples with relatively normal semen parameters should have sex daily for up to a week before the ovulation date. In addition, these results may mean that men play a greater role in infertility than previously suspected, and that ejaculatory frequency is important for improving sperm quality."
Greening said he thought the reason why sperm quality improved with frequent ejaculation was because the sperm had a shorter exposure in the testicular ducts and epididymis to reactive oxygen species, high levels of which can damage cells.
Source: European Society for Human Reproduction and Embryology