Men whose mothers were exposed to stressful life events while they were in the first 18 weeks of pregnancy may have reduced sperm counts when they become adults, according to a study published in Human Reproduction.
Research has shown that the first few months of pregnancy is when male reproductive organs are at their most vulnerable stage of development. This current study of 643 young men aged 20 found that those who were exposed to at least one stressful life event during early gestation (0-18 weeks) had worse sperm quality and lower testosterone concentrations than those who were not exposed, or who were exposed during later gestation, between 18-34 weeks.
The findings come from the Western Australia’s Raine Study, a multi-generational study that recruited nearly 3,000 women in their 18th week of pregnancy in the period between May 1989 and November 1991. The mothers completed questionnaires at 18 and 34 weeks’ gestation, and each survey included questions about stressful life events during the preceding four months of pregnancy. These events included death of a close relative or friend, separation or divorce or marital problems, problems with children, mother’s or partner’s involuntary job loss, money problems, pregnancy concerns, moving home or other problems.
The researchers found that the men who had been exposed to three or more stressful life events during early gestation had an average of 36% reduction in the number of sperm in their ejaculate, a 12% reduction in sperm motility and an 11% reduction in testosterone levels compared to those men who were not exposed to any stressful life event during that period.
“This suggests that maternal exposure to stressful life events during early pregnancy, a vulnerable period for the development of male reproductive organs, may have important life-long adverse effects on men’s fertility,” said senior author Roger Hart, Professor of Reproductive Medicine at the University of Western Australia and medical director of the Fertility Specialists of Western Australia IVF unit.
Hart said that exposure to stressful life events during early pregnancy was unlikely to cause a man to be infertile by itself, but when added to other factors, it could contribute to an increased risk of infertility.