Children whose grandmothers were stressed during pregnancy are more likely to suffer from mental health problems, a study has suggested.
Research on rats discovered that maternal stress in females was passed on not only to their young but to the next generation of offspring too.
The University of Edinburgh study is the first to find evidence that greater levels of mental illness linked to differences in the genes that regulate emotions could be transmitted through multiple generations.
The link between maternal stress and mental illness is thought to relate to how hormones released in response to stress affect the developing baby’s brain.
Experts said the findings had long-term health implications not only for the unborn children of pregnant women but also for future generations. Researchers hope the findings will help in developing new ways to relieve stress in mothers and discovering new treatments for mental illnesses such as depression and anxiety.
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Paula Brunton, who led the study at the university’s Roslin Institute, said: “This suggests that your life history from before you were born, or even from before your mother was born, could have an impact on your mental health.
“We have no reason to expect that the same sort of effect [as in rats] would not happen in women and children because the systems involved are almost exactly the same, with the same hormone release in response to stress and the same pathways of hormones in the brain.
“There have been a lot of studies which have shown, not only in animals but in humans too, that stress can have an impact on the first generation. This research is the first one that shows it can do that across generations too.”
In the paper, published in the journal Psychoneuroendocrinology, the authors state that the findings have implications for “the management of pregnant women in order to promote healthy long-term outcomes for their children, and indeed future generations”.
Researchers now plan to focus on improving their understanding of how prenatal stress is transmitted through generations. They hope that analysis could help to develop new therapies and other ways of treating mental health conditions.
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In evolutionary terms, maternal stress is thought to have had beneficial results in some cases by signalling a hostile environment, such as the presence of predators. Passing on greater anxiety to offspring could aid their survival by making them more vigilant.
The research was supported by the Biotechnology and Biological Sciences Research Council.
Melanie Welham, the council’s executive director for science, said: “The factors that can influence health throughout our life course, including before birth, are an important and intriguing area of study to fully understand bioscience for health.
“This study in rats adds to our understanding of the effects that maternal stress may have on future generations.”
The National Childbirth Trust welcomed the potential future benefits that the research could bring but said that urgent work was needed now to improve inadequate support services for the many women experiencing mental health issues including stress, anxiety and depression during pregnancy and after birth.