Second Pregnancy Causes Distinct Brain Changes, Study Shows
A new study reveals that a second pregnancy uniquely alters the female brain, with distinct changes in attention and sensory networks compared to the first pregnancy. The research also links brain changes to mother-child bonding and peripartum depression.
A second pregnancy brings patterns of brain changes that are both similar to and distinct from those of a first pregnancy, according to research published in Nature Communications. The study followed 110 women over time — some expecting their first child, some pregnant with a second, and others remaining childless — using repeated MRI brain scans to track structural and functional shifts.
"With this, we have shown for the first time that the brain not only changes during the first pregnancy, but also during a second," said Elseline Hoekzema, head of the Pregnancy Brain Lab at Amsterdam UMC. "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."
During a first pregnancy, the largest changes occurred in the structure and activity of the brain's Default Mode Network, a system involved in self-reflection and social thinking. In a second pregnancy, this network changed again but to a lesser degree. Instead, the most noticeable changes emerged in networks responsible for directing attention and responding to sensory information.
"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," explained researcher Milou Straathof. "These processes may be beneficial when caring for multiple children."
The study also found a link between pregnancy-related brain changes and the emotional bond between mother and child, a relationship that was stronger after a first pregnancy than a second. Additionally, researchers identified the first evidence that structural changes in the brain's cortex during pregnancy are associated with peripartum depression. For first-time mothers, these associations were most apparent after childbirth; for women expecting a second child, they were more noticeable during pregnancy.
"This knowledge can help to better understand and recognize mental health problems in mothers. It is important that we understand how the brain adapts to motherhood," the researchers noted. The findings offer new insight into the adaptability of the maternal brain and could eventually improve care for mothers, including efforts to prevent and treat postpartum depression.