Pregnancy affects not only a woman's body: It changes parts of her brain, too, a new study published in Nature Neuroscience says. 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, were mostly still present two years after childbirth. (Based on prior research findings, the researchers think the brain changes happened during pregnancy). No brain changes were seen in first-time fathers, reports the AP.
What's going on? Elseline Hoekzema, a study author at Leiden University in the Netherlands, and colleagues think the differences result from sex hormones that flood the brain of a pregnant woman. In 11 places in the brain, 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 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, perhaps to prepare a woman for motherhood. One analysis linked brain changes to how strongly a woman felt emotionally attached to her infant.