Stress During Pregnancy Likely To Affect Your Baby’s Brain

Taking stress during pregnancy is not good for your baby—another research reasons it with its surprising study results. The stress that mother experiences can pass from the mother to the baby during birth and you just can’t imagine how.

It is through the bacteria in your vagina that the baby gets affected. There are more bacteria that are living inside us than the cells present in our body—most of them are found in our digestive tract.1 The good bacteria help in absorbing nutrients and strengthening our immune system—they are our allies.


Your baby gets the first exposure to the bacteria from the mother’s vagina during birth. These bacteria then reach the baby’s gut—don’t ask how—and start multiplying. The research targeted these gut bacteria in mice to study their impact on the baby’s brain development and finding whether the stress encountered during pregnancy affects the baby in any way.

The study was conducted by Chris Howerton and his team at the University of Pennsylvania.


Studying The Vaginal Bacteria

Scientists created two groups of pregnant mice—one group containing 10 mice were introduced to stress on a regular basis. Stressful situations included exposing them to fox odor and keeping their cages lit at night—a set of psychologically stressful events that were different from their normal day. The rest of the mice had a happy pregnancy.

To study the kind of bacteria that the bodies of these mice hosted, the scientists took some samples of their vaginal bacteria during their pregnancy and after the delivery.


The Results

There was a difference in the type of bacteria found in mice mothers who were stressed and those who weren’t. The stressed mice had more types of bacteria, but a significant gut bacteria called Lactobacillus had reduced in count—the same bacteria is largely responsible for breaking down the food, absorbing nutrients and fighting infections.

Studying The Effect Of Stress On Babies

After the birth of the baby mice or pups, studying a sample of their gut bacteria, it was found that the type of bacteria was similar to those found in the stressed mother mice.


The team also studied the brain area that was responsible for hormones control, behavior and sleep in the pups. Due to the reduced count of Lactobacillus bacteria, as many as 20 genes were impacted including the genes responsible for new nervous connections inside the brain.

Such a deep impact was attributed to the change in metabolism and type of nutrients due to the decrease in the number of gut bacteria. The blood that circulated in the body of these pups had fewer elements that are required for formation of chemicals that help in transmitting signals to the brain.


Tracy Bale, director of the University of Pennsylvania lab told that these tiny changes are a lot more significant in determining how the brain of the pups will respond to the stress in future. A considerable change in the count of microbes could also affect the immune system of the animal.
All in all, it was concluded that the bacteria count in the body passed from the mother does play an important role in the other body mechanisms.

Howerton says that as humans we can still control the bacteria count in newborns of stressed mothers by injecting them with a dose. This could also be helpful for babies who are born via c-section and missed upon receiving the essential bacteria from the mother. It could also prove beneficial for newborns of those mothers who had antibiotics during pregnancy, which affected their gut bacteria.


Tracy is also keen on finding out if this is the case with humans—whether the moms who have had traumatic experiences affected their babies’ gut bacteria.

She also considers the fact that what makes a person unique is the brain. If these tiny microbes could act as a factor in affecting our brains, it becomes equally important to understand how these factors bring about these changes.


Above all, one thing is for sure—stress is bad for you and your baby under all circumstances.