Pregnancy stress linked to lower sperm count in male offspring

A link between mothers who undergo distressing events during the first 18 weeks of being pregnant and having a boy with a lower sperm count once grown up.


Pregnancy is a time of many changes. A pregnant lady can add new stresses to your life. Feeling stressed is common during pregnancy. But too much stress can be uncomfortable. Stress can trouble a pregnant woman while sleeping. It may also cause headaches, etc.

It’s been said that pregnancy stress causes a bad impact on both mother and child. A new study has added power to this fact, suggesting stress in early pregnancy may affect a woman’s chances of having grandchildren.

Scientists identified a link between mothers who undergo distressing events during the first 18 weeks of being pregnant and having a boy with a lower sperm count once grow up. They believe the developing male reproductive organs are at their most vulnerable during this time.

For the study, scientists recruited 643 men aged 20 and their mothers. They tested the men for sperm count and testosterone concentrations and compared this to the results of a questionnaire to their mothers. 63 percent of the men had been exposed to at least one stressful life event in early gestation, while fewer stressful life events occurred in late gestation.

Those who were exposed to stressful life events in early gestation had lower total sperm counts, fewer sperm that could swim well, and lower concentrations of testosterone than those exposed to no events.

Scientists had found only an association between stressful life events in early pregnancy and reduced sperm quality and testosterone concentrations in offspring, not that one definitely caused the other.

Study senior author Professor Roger Hart, from UWA’s Medical School and medical director of the Fertility Specialists of Western Australia IVF unit said, “We found that men who had been exposed to three or more stressful life events during early gestation had an average of 36 percent reduction in the number of sperm in their ejaculate, a 12 percent reduction in sperm motility and an 11 percent 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. This contrasts with the absence of any significant effect of exposure to maternal stressful life events in the late gestation.”

Professor Hart said that exposure to stressful life events during early pregnancy was unlikely to be the sole cause of male infertility, but when added to other factors could contribute to an increased risk.”

“Like most things in life, if exposure to stressful life events in early gestation is added to other things that are known to affect men’s fertility, it may contribute to an increased risk of male infertility.”

“These may include being overweight or obese, smoking, excessive alcohol intake, high blood pressure, high cholesterol, sugar, or fat levels in the blood, or exposure to chemicals in the environment that interfere with natural hormones, both before birth and in adulthood.”

“Our findings suggest that improved support for women, both before and during pregnancy, but particularly during the first trimester, may improve the reproductive health of their male offspring.”

“Men should also be made aware that their general health is also related to testicular health, so they should try to be as healthy as possible to ensure that not only do they have the best chance of maintaining fertility, but also of remaining healthy in later life.”

“To provide some perspective, the association between exposure to stressful life events and reduction in sperm counts was not as strong as the association between maternal smoking and subsequent sperm counts, as this was associated with a 50 percent reduction in sperm number.”

The study was conducted by The University of Western Australia with scientists from the University of Copenhagen in Denmark, The University of Sydney, and The University of Melbourne.

Journal Reference

  1. E V Bräuner, Å M Hansen, D A Doherty, J E Dickinson, D J Handelsman, M Hickey, N E Skakkebæk, A Juul, R Hart; The association between in-utero exposure to stressful life events during pregnancy and male reproductive function in a cohort of 20-year-old offspring: The Raine Study. Human Reproduction, Volume 34, Issue 7, July 2019, Pages 1345–1355, DOI: 10.1093/humrep/dez070
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