A new study from Columbia University’s Mailman School of Public Health in New York and Rutgers School of Public Health in Poscataway, NJ, investigated the effects stress has on sperm quality and quantity. Their findings revealed that higher levels of stress may hurt the quality of men's sperm. The results  do not prove cause-and-effect, since there is a possibility that stressed-out men share another trait that disrupts their reproductive systems. Also, it is not clear if men with more stress are actually less fertile.

Approximately 40 percent of infertile couples shows that the male counterpart is either the sole reason or contributing reason of infertility, according to the American Society for Reproductive Medicine. The main cause of infertility is due to sperm defects, such as low sperm production or stationary sperm.

Published in the journal Fertility and Sterility, the researchers evaluated 193 men aged 38 to 49, who were a part of the Study of the Environment and Reproduction at the Kaiser Foundation Health Plan in Oakland, CA.

The researchers found that men who experienced two or more stressful life events in the past year had a lower percentage of sperm motility and a lower percentage of sperm of normal shape, compared with men who did not experience any stressful life events. They added that this finding remained even after accounting for other factors that may influence semen quality, such as age, other health problems and history of reproductive health problems.

Study lead author Teresa Janevic, an assistant professor at Rutgers School of Public Health's Department of Epidemiology in Piscataway, N.J, points out that, “It's very possible that the levels of work stress in the men in our study were not high enough to see an effect.” She did add that the sperm with the worst shape were found in unemployed men compared to men with jobs.

More studies are needed to find the cause of the reduced semen quality, but this is a starting point.

Additional Resources:

Effects of work and life stress on semen quality