Second pregnancy alters the female brain

A second pregnancy alters the female brain in ways distinct from a first, according to research examining how motherhood affects brain structure and function.

The study tracked 110 women using repeated brain scans. Some became mothers for the first time, others had a second child, while a third group remained childless, allowing researchers to identify pregnancy-related brain changes.

During a first pregnancy, the greatest changes occurred in the default mode network, a brain system involved in self-reflection and social processes. During a second pregnancy, this network changed again, but less strongly.

Instead, a second pregnancy was associated with more changes in brain networks linked to directing attention and responding to stimuli, functions that may be useful when caring for more than one child.

Each pregnancy produced both shared and distinct effects on the brain, with patterns differing between first and second pregnancies.

Elseline Hoekzema, head of the Pregnancy Brain Lab at Amsterdam UMC, said: “With this, we have shown for the first time that the brain not only changes during the first pregnancy, but also during a second. During a first and second pregnancy, the brain changes in both similar and unique ways. Each pregnancy leaves a unique mark on the female brain.”

Milou Straathof, a researcher who analysed the data, said: “It appears that during a second pregnancy, the brain is more strongly altered in networks involved in reacting to sensory cues and in controlling your attention. These processes may be beneficial when caring for multiple children.”

The researchers also found a link between brain changes and the bond between mother and child, which was more pronounced during a first pregnancy than a second. They also observed associations between structural brain changes and peripartum depression, a form of depression that can occur during pregnancy or after birth, in both first and second pregnancies.

This provides the first evidence that changes in the cortex, the brain’s outer layer, during pregnancy are linked to maternal depression.

For women who became mothers for the first time, this link was especially visible after childbirth. For women having their second child, it was particularly apparent during pregnancy.

The researchers said: “This knowledge can help to better understand and recognise mental health problems in mothers. It is important that we understand how the brain adapts to motherhood.

They added that the findings could support better care for mothers, including the prevention and treatment of postnatal depression. Although most women experience pregnancy once or multiple times, scientists are only beginning to understand how it affects the brain.