The Baby’s Got Her Eyes, Her Nose and Her Stress

Pregnancy is naturally stressful. But too much prenatal stress can change the DNA of a fetus, leading to long-term behavioural impacts.


Growing a tiny human is hard work. While the pregnant body is piecing together a little bundle of joy, soon-to-be parents are fretting about, well, everything. It’s not surprising moms-to-be are stressed.

Of course, some stress is normal. But for a developing fetus, exposure to stress can have long-term implications. Researchers have long known that prenatal stress is associated with higher risk for behavioural and psychiatric disorders. But now we have a better idea of how this happens.

Led by Nadine Provençal, an assistant professor of health sciences at Simon Fraser University, a team of international researchers recreated the impact of stress on the fetal brain by exposing developing fetal neurons to high levels of stress hormones in the lab.

This stress caused structural changes in the DNA, changes that lasted long after the stressors were removed.

The researchers describe these changes as epigenetic marks, a type of “cellular memory” that primes neurons to be more responsive to stress in future. This finding could help explain why some individuals are more sensitive to stress later in life.

Next, the researchers wanted to confirm whether their findings would translate from lab to life. To do this, they studied umbilical cord blood from newborns exposed to prenatal stress, depression or anxiety. Again, the patterns were similar.

“The prenatal period is one of the most dynamic and sensitive periods in a person’s life,” explains Provençal. “Prenatal stress experienced by the mother during pregnancy not only impacts the mother’s health but can also impact her developing fetus.

“Our research demonstrates an association between the epigenetic mark, or cellular memory, and an increased response to stress hormones, which could help to explain why some individuals are more vulnerable to stress later in life.”

For parents-to-be, pregnancy is an inherently stressful time. These findings highlight the potency of stress, and the importance of stress-management during the delicate prenatal period. While it’s not always possible to stay stress-free, helping moms-to-be mitigate and manage stress could have benefits long into the future.

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Amy Noise is a science communicator who is fascinated by how and why the world works. Always learning, she is passionate about science and sharing it with the world to improve and protect our health, society and environment. Amy earned her BSc (biology and science communication) at the University of Manchester, and MSc (nutrition science and policy) at King’s College London, UK. She tweets sporadically @any_noise