Prolonged stress, such as that experienced during military conflict, can have an adverse impact on sperm quality, according to a new study by researchers at Ben-Gurion University of the Negev (BGU) and Soroka University Medical Center in Beer-Sheva, Israel.

The study, which was presented last week at the International Summit on Assisted Reproduction and Genetics in Israel, indicated that more than a third (37%) of the sperm samples taken during a stressful period were found to have low sperm motility.

“Mental stress is known to have an adverse effect on fertility, but there is little research on the impact of stress on sperm quality,” says Dr. Eliahu Levitas, a member of the Ben-Gurion University Faculty of Health Sciences and director of the IVF Unit at Soroka. “This study shows that prolonged stress can have an effect on sperm quality.”

In general, the probability of weak motility in sperm samples taken during periods of prolonged stress was 47% higher. Weak motility makes it less likely that the sperm will successfully fertilize an egg.

The study included 10,536 samples donated during unstressful periods between 2009-2017, which were compared to 659 sperm samples taken during and up to 2 months after two military conflicts between Israel and Gaza in 2012 and 2014. The subjects’ average age was 32, and 44% were smokers.

According to Dr. Levitas, who is also director of the Soroka Sperm Bank, “Our reasoning was that even men who heard incoming rocket warning sirens during a conflict experienced stress throughout the day over a longer period. We were surprised to discover that there is a connection between the security situation and the sperm counts.”