Study of 40 first-time fathers finds that fatherhood changed their brains in ways that could help them be better parents

Centers for Disease Control and Prevention photo

A growing body of research finds that children with engaged fathers do better on a range of outcomes, including physical health and cognitive performance, and a new study finds that fatherhood causes changes in the brain in ways that could influence their parenting, Darby Saxbe and Magdalena Martinez Garcia report for The Conversation, a platform for journalistic writing by academics.

Garcia, who works at the Instituto de Investigación Sanitaria Gregorio Marañón in Madrid, Spain, was the lead author on the study. Saxbe, of the University of Southern California in Los Angeles, contributed to the research.

Despite fathers' increasing participation in child care, they note, there is surprisingly little research about how fatherhood affects men, and even fewer studies focus on the brain and biological changes that might support fathering. Since pregnancy-related hormonal changes help explain why a new mother's brain might change, they explored whether fatherhood also reshapes the brains and bodies of men, in a study of first-time fathers in Spain and California.

Spanish researchers had scanned first-time mothers before conception and two months after delivery, and found that compared to childless women, "The new mothers’ brain volume was smaller, suggesting that key brain structures actually shrank in size across pregnancy and the early postpartum period," Saxbe and Garcia report. "The brain changes were so pronounced that an algorithm could easily differentiate the brain of a woman who had gone through a pregnancy from that of a woman with no children." They also found changes across the brain's gray matter, the layer that is rich in neurons, and changes in the cortex, which is linked to thinking about others, and the subcortex, which is linked to more primitive functions, including emotion and motivation.

The authors say experience-induced brain plasticity happens when you learn a new language or master a new musical instrument, and suggest that this could also happen with the new experience of caring for an infant. They note that there is a small, but growing body of research being done on this topic. 

To learn more about plasticity in new dads’ brains, the researchers studied 40 expectant fathers who were put into an MRI scanner twice: during their partner’s pregnancy, and after their baby was 6 months old. The study also included a control group of 17 childless men.

"We found several significant changes in the brains of fathers from prenatal to postpartum that did not emerge within the childless men we followed across the same time period," they report. "In both the Spanish and Californian samples, fathers’ brain changes appeared in regions of the cortex that contribute to visual processing, attention and empathy toward the baby." They offer the possibility that the brain plasticity in fathers may be tied to how much they interact with their baby, and say that raises the question of whether family policies that increase the amount of time a father can spend with their child during the early postpartum period could help to support the development of the fathering brain. 

"Spanish fathers, who, on average, have more generous paternity leaves than fathers have in the U.S., displayed more pronounced changes in brain regions that support goal-directed attention, which may help fathers attune to their infants’ cues, compared with Californian fathers," they write. However, men who show more remodeling of the brain and hormones may be more motivated to participate in hands-on care. The authors called for more research, noting that future studies with more detailed measures of postpartum caregiving can reveal more about parental brain plasticity in both men and women.