First Trimester Stress Linked to Brain Disorders

A new study draws a connection between a mom's stress levels early in pregnancy, during the first trimester, and the mental health of her baby. Here's what to do.

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Stress and early parenthood inevitably go hand in hand. But unnecessary stress during pregnancy should be avoided if possible for a few newly specified reasons, according to a study published in Endocrinology. It seems that stress can actually affect the microbes that reside in an expectant mother's vagina, which, in turn, are transferred to the newborn during vaginal birth, resulting in changes to the little one's gut microbiome and brain development. As a result, these changes have an impact on the infant's immune system and metabolism. In fact, scientists believe that the altered gut microbiota is linked to a greater risk of neurodevelopmental disorders, including autism and schizophrenia.

Stress in pregnancy

These effects were observed in a University of Pennsylvania lab in pregnant mice who had to endure such stressors as unfamiliar noises, predator odors, and being restrained. This all occurred during early gestation, or what might be considered the first trimester, and the offspring of these mice experienced negative outcomes with regard to their metabolism and amino acid processing in the brain. Interestingly, the effects were more dramatic in male mice than in females.

"We were very surprised in our observation that effects of stress so early in pregnancy lasted so long, resulting in a stable and long-term change to the mother's vaginal microbiota, and that these same changes were passed on to the offspring," postdoctoral researcher and study author Eldin Jašarevi says.

The critical first trimester

The team of Penn researchers found that the first trimester was a particularly critical window of time when stress exerts its greatest impact. "These results would suggest that stress might exert an effect on her offspring's development well before the woman discovers she is pregnant," JaÅ¡arevi advises. "Our findings in our mouse model are consistent with epidemiological studies indicating that the first trimester is a dynamic and critical period to a variety of environmental factors—stress, infection, and malnutrition—that have been associated with an increased risk for neurodevelopmental disorders, such as autism, schizophrenia, and ADHD."

Some of the team's previous work also looked at stress during mid and late pregnancy, but they didn't find these periods to be as vulnerable. Still, other studies in different animal models have discovered that chronic and unpredictable stress during any stage of pregnancy might lead to a variety of negative outcomes, according to Jašarevi.

What about C-sections?

It's worth nothing that babies delivered by C-section are not exposed to the mother's vaginal microbes. (Instead, their guts are likely to be colonized by bacteria from their mother's skin or the hospital environment.) In these cases, one might expect that maternal stress has less of an impact on the newborn. But the researchers claim that they've separately observed how maternal stress still influences the "transmission of critical nutrients necessary for neurodevelopment" well before labor and childbirth.

Given that these investigations involved animals and not human participants, the results should be taken with a grain of salt. Nevertheless, relieving stress during pregnancy is a good idea for any soon-to-be mom. As far as how much stress is too much stress, it's hard to say. Jašarevi knows that responses are highly individual, and usually determined by genetics and the environment. Some people can shoulder a lot of it, while others can't.

If you're feeling tense, under a lot of pressure, or stretched too thin, take a 5-minute break to practice some controlled breathing. Other methods for relieving stress include listening to calming music, stretching, yoga or kickboxing, meditating, drinking peppermint tea, and sniffing lavender essential oil. You'll not only be giving yourself some much-needed relief, but your baby may benefit as well.