Brain study identifies a cost of caregiving for new fathers
Parenting makes the heart grow fonder, and the brain grow … smaller? Several studies have revealed that the brain loses volume across the transition to parenthood, Darby Saxbe, a psychology professor at the University of Southern California, writes for The Conversation. However, researchers are still determining the significance of these changes for parents.
In a 2024 study examining brain changes in first-time fathers, Saxbe and her colleagues found that brain volume loss was associated with increased engagement in parenting, as well as more sleep problems and mental health symptoms. These results might point to a cost of caregiving, traditionally shouldered by women but increasingly taken on by men, as the author also says.
Brain changes for mom come with new baby
Caring for an infant demands new motivations and skills, so it is no surprise that it might also sculpt the brain. Research in rodents first identified remodeling of both the structure and function of the brain during pregnancy and parenthood. A new body of research is also uncovering similar effects in human parents.
In a pair of studies, researchers recruited first-time mothers for a brain scan conducted before they became pregnant, then scanned them again a few months after giving birth. Gray matter—the layer of brain tissue that contains neuronal cell bodies—shrank in the mothers but not in a comparison group of women who did not become mothers.
Although a shrinking brain sounds undesirable, researchers theorize that this more streamlined brain could be adaptive, enabling it to process social information more efficiently and thereby facilitating sensitive caregiving. In keeping with this hypothesis, studies have linked maternal brain changes with women’s degree of attachment to infants and with their responses to images of their infants. Women who lost more gray matter volume also appeared more bonded with their babies.
New dads’ brains change, too.
Most studies of the parental brain have focused on women; however, emerging evidence suggests that similar brain changes may also occur in new fathers. The USC team had previously identified brain volume loss in men transitioning to fatherhood, in comparable parts of the brain that changed in mothers.
Before you picture the shrunken-head guy from the movie “Beetlejuice,” keep in mind that these changes were subtle. Fathers showed fewer, less statistically significant brain changes than mothers.
Dads vary in their level of investment in caring for the baby, so as a next step, we wanted to know how men’s brain changes across the transition to fatherhood map onto their experiences of new parenthood.
To test this question, the researchers examined 38 men in California more closely, scanning them before and after their babies’ birth. During pregnancy and again at three, six, and 12 months postpartum, the team asked the fathers how they felt about their infants and how well they slept. They also asked about their symptoms of depression, anxiety, or other mental health problems.
As before, they observed significant prenatal-to-postpartum brain differences across the entire cortex, the brain’s outermost layer that performs many higher-order functions, such as language, memory, problem-solving, and decision-making. On average, men in the sample lost about 1% of their gray matter volume across the transition to parenthood.
Consistent with the research on mothers, men’s brain volume reductions did indeed seem to track with their parenting. If men said during pregnancy that they wanted to take more time off from work after the birth, and felt more bonded to their unborn child, they subsequently lost more gray matter volume, especially in the frontal and parietal lobes—parts of the brain involved in executive functioning and sensorimotor processing, respectively.
Greater volume loss also emerged among fathers who reported spending more time with their infants at three months postpartum, taking more pleasure interacting with their infants, and experiencing less parenting stress. Taken together, the results aligned with prior studies on mothers and suggested that more motivated, hands-on fathers experienced greater loss of gray matter volume during their transition to parenthood.
The plot thickened when researchers looked at mental health and sleep quality. Men who lost more brain volume also reported greater depression, anxiety, general psychological distress, and worse sleep at both six and 12 months after birth. These results held up when controlled for the same measures during pregnancy.
This finding provides a clue to a possible direction of causality: Rather than prenatal sleep problems or psychological distress predicting greater brain change, the team found instead that fathers’ gray matter volume loss preceded their postpartum sleep problems and mental health, above the effect of their well-being before birth.
Parenting comes with highs and lows
Importantly, this research is preliminary: USC had a small sample of fathers willing to participate in the intensive research study. These results need to be replicated in larger and more representative groups of fathers.
Still, as one of the first longitudinal studies of male brain changes across the transition to first-time parenthood, the findings illustrate that perinatal brain changes may reflect adaptation and vulnerability. The very same changes linked with fathers’ greater investment in caregiving also seemed to heighten their risk of sleep trouble and mental health problems.
As any new parent will tell you, caring for an infant is challenging. Becoming a parent forces a realignment of life priorities and can bring magic and meaning to everyday life. But parenting can also be dull, repetitive, lonely, and draining.
Perhaps these findings in fathers point to a cost of caregiving. This burden has long been familiar to mothers but may be increasingly shared by men as fathers step up their participation in hands-on parenting.
The take-home message here is not that men should stop caring for children. A slew of research suggests that children with involved fathers do better across the board: academically, economically, and emotionally. Fathers report that parenthood makes their lives richer and more fulfilling.
Instead, results like these support public health priorities that invest in fathers—and parents in general—through policies that reduce stress for new parents in the first months after birth, such as paid leave and workplace efforts to normalize leave-taking among men.
This story was produced by The Conversation and reviewed and distributed by Stacker.
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