Pregnancy Changes a Mother's Brain Structure and Size for Years

Can having a baby change your brain? Science says "yes" and the changes stick around for years. WIN-Initiative/Getty Images

For any woman who has become a little more forgetful as pregnancy has progressed, there's validation in a recent scientific report, which indicates that "pregnancy brain" is real — and lasts longer than previously thought.

While many are familiar with the "momnesia" that can occur during gestation, a new study published in the journal Natural Neuroscience contends that — along with sweeping hormonal, emotional, chemical and outward physical changes — pregnancy alters regions of the brain for up to two years after a woman gives birth. These marked changes are also incredibly useful, aiding a mother's ability to bond with and give undivided attention to a newborn.

These pregnancy-induced brain changes involve the pruning of the size and structure of certain areas of the brain that process social information, such as the feelings, intentions, thoughts or beliefs of others.

The colored areas of these brain scans show regions with volume changes following a pregnancy.
Oscar Vilarroya

Using magnetic resonance imaging (MRI), a team of scientists lead by Oscar Vilarroya and Susanna Carmona, of the Autonomous University of Barcelona, analyzed the MRIs of 25 first-time mothers before and after their pregnancies, and 19 of their male partners. They also analyzed a control group of 20 women who had never been pregnant, as well as 17 additional male partners.

Over a five-year period, the researchers took MRI scans of the study participants at regular intervals, and these scans revealed changes in the pregnant women's brains. Specifically, there was a reduction in grey matter in the prefrontal and temporal cortexes, which are the areas that correspond with social cognition and self-focused processing. Interestingly, these deficits did not create a cognitive struggle, but actually enhanced certain functions.

"The findings point to an adaptive process related to the benefits of detecting the needs of the child," said Vilarroya in a press release, "such as identifying the newborn's emotional state."

The changes to pregnant women's brains, as shown in the scans, were so prevalent and consistent that scientists could tell whether a woman had been pregnant before based just by looking at a brain scan. Scientists also were able to predict a mother's attachment to her newborn based on brain changes.