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Brain changes seen in pregnancy may help prepare for baby

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 were also 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 in Spain. She and colleagues presented 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 the 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 follow-up with 11 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.

Hoekzema and colleagues think the differences result from sex hormones that flood the brain of a pregnant woman.

In a separate study, scientists found that US women are increasingly using marijuana during pregnancy, sometimes to treat morning sickness. Though the numbers are small, the trend raises concerns because of evidence linking the drug with low birth weights and other problems.