Multiple brain changes seen during pregnancy

new york» Pregnancy affects not only a woman’s body: It changes parts of her brain too, a new study says.

When researchers compared brain scans of women before and after pregnancy, they spotted some differences in 11 locations. They also found hints that the alterations help women prepare for motherhood.

For example, they might help a mother understand the needs of her infant, Elseline Hoekzema, a study author at Leiden University in the Netherlands, explained via e-mail.

The women also were given memory tests, and they showed no signs of decline.

Hoekzema, a neuroscientist, began working on the study while at the Autonomous University of Barcelona. She and colleagues present the results in a paper released Monday by the journal Nature Neuroscience.

The study includes data on 25 Spanish women scanned before and after their first pregnancies, along with 20 women who didn’t get pregnant during the study. The brain changes in the pregnancy group emerged from comparisons of those two groups.

The results were consistent: A computer program could tell which women had gotten pregnant just by looking at results of the MRI scans.

And the changes, first documented an average of 10 weeks after giving birth, mostly were present two years after childbirth. That’s based on follow-up with 11 study participants.

Further work showed they’re a motherhood thing: No brain changes were seen in first-time fathers.

Based on prior research findings, the researchers think the brain changes happened during pregnancy rather than after childbirth.

What’s going on? Hoekzema and colleagues think the differences result from sex hormones that flood the brain of a pregnant woman. In the 11 places, the MRI data indicate reductions in volume of the brain’s gray matter, but it’s not clear what that means.

For example, it could reflect loss of brain cells or a pruning of the places where brain cells communicate, called synapses.

Losing some synapses is not necessarily a bad thing. It happens during a hormonal surge in adolescence, producing more specialized and efficient brain circuits. The researchers suspect that could be happening in the pregnant women.

Some study results hint that such upgrades may prepare a woman for motherhood.