A second pregnancy does not simply repeat the brain changes of the first. It rewires the mother's brain in its own distinct pattern, according to new research from Amsterdam University Medical Center in the Netherlands.
Published in Nature Communications, the study followed 110 women over time. Some were pregnant with their first child, some with their second, and others were not pregnant. Repeated brain scans allowed researchers to track how the brain changed across each pregnancy.
First pregnancy targets the default mode network
During a first pregnancy, the largest changes appeared in the brain's Default Mode Network. This system is involved in self reflection, social thinking, and other core mental functions. The changes were significant in both structure and activity.
Second pregnancy shifts attention and sensory networks
When women became pregnant a second time, the Default Mode Network changed again but to a lesser degree. Instead, the most noticeable shifts occurred in networks that control attention and respond to sensory information. Researcher Milou Straathof, who analyzed the data, said these changes may help a mother care for multiple children at once.
Brain changes linked to bonding and depression risk
The study also found a connection between pregnancy related brain changes and the emotional bond between mother and child. That link was stronger after a first pregnancy than after a second. Researchers also identified ties between structural changes in the brain's cortex and peripartum depression during both first and second pregnancies. This is the first evidence linking cortical changes during pregnancy to maternal depression. The timing differed: for first time mothers, the association was strongest after childbirth. For women expecting a second child, it was more noticeable during pregnancy.
Elseline Hoekzema, head of the Pregnancy Brain Lab at Amsterdam UMC, said the findings show for the first time that the brain changes not only during a first pregnancy but also during a second. Each pregnancy, she noted, leaves a unique mark on the female brain.
These results open a new window into maternal mental health. By understanding how each pregnancy reshapes the brain differently, researchers may eventually find better ways to recognize and treat conditions like peripartum depression.
