Women who have given birth often file the same complaint: They can’t seem to focus as sharply as they did before motherhood. The body visibly and hormonally changes during pregnancy and after labor, but it’s harder to see what’s happening to the mind. One expert, Pilyoung Kim, director of the Family & Child Neuroscience Lab at the University of Denver, has looked into the gray matter of new mothers. Here she explains the reasons behind the fog of the so-called Mommy Brain and why rodents may provide evidence that being a parent makes people more productive.
On Becoming a Mother
Even before the baby is born, certain parts of the brain show a structural increase as well as greater function. This continues for about three or four months after birth. “We see evidence of this in areas of the brain related to maternal instinct, and also in the reward centers,” says Dr. Kim, whose Denver lab studies the parental brain. This growth urges new mothers to bond with their babies, take care of them and think about them constantly. Researchers have also shown an increase in activity and structure in the prefrontal cortex, which is responsible for executive functions, such as decision making, learning and emotion regulation.
Becoming a mother is “actually a gradual neurological and psychological process,” Dr. Kim says.
A Time of Anxiety
All those urges to nurture can result in anxiety, which is why many mothers worry constantly about their baby’s health. That anxious feeling should diminish as mothers become more confident in their parenting skills. “When we follow parents over time, the anxiety decreases gradually over a few months, as they learn how to take care of and interact with their babies, and the babies become more independent,” Dr. Kim says.
Dr. Kim believes that it’s only natural to feel like you don’t have time in the day for things that used to be important—taking care of yourself, seeing friends, getting work done—because the brain is trying so hard to adapt to its new circumstance, “and there are only 24 hours in a day,” she adds.
“If we borrow from animal research, we can extrapolate there is evidence to suggest that multiple pregnancies enhance memory,” she says. Rodents, Dr. Kim explains, show increased hippocampus function after giving birth multiple times, becoming increasingly better at remembering where to find food. “For them, sourcing food is critical to raising their babies.”
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In humans, she says, it’s possible that the brain similarly adapts to become better at remembering certain things, and to work more efficiently and productively, in order to have more time to allocate to parenting. Researchers are still in the process of finding strong evidence to support the notion that working mothers may be more productive than they were before they had babies, says Dr. Kim, “but I wouldn’t be surprised if this were proven true.”
New fathers, too, show an increase in brain activity during the first few months postpartum. In Dr. Kim’s own published studies, “there were fewer brain areas affected compared to mothers,” she says. The striatum, the parental-instinct region of the brain, was one of the areas that showed a structural increase in fathers.
However, she cautions, it’s hard to tease out if researchers see fewer changes in dad brains because fathers typically spend less time with their newborns and infants as they head back to work. Though they show less amount of the “love hormone” oxytocin that comes from breastfeeding, fathers do show an increase in that chemical, as well as the feel-good hormone dopamine in response to interaction with their babies; their response just might be even more gradual than for mothers during the early post-partum period.
Lasting Brain Changes
Dr. Kim’s most recent paper is not published, but preliminary results show that the cortical layers, where the connections between neurons lie, become thicker during the first six months postpartum. One of them, the prefrontal cortex, plays a major role in memory, attention, language and emotion. A few months after having a baby, you may even feel smarter, more confident and better able to concentrate on nonmaternal work, whether that be office work or helping a friend.
Parenting is clearly critical work, says the neurologist, since the dramatic growth in the brain that stems from it is not common during any other period of adulthood. “We see this amazing plasticity in the brain during the early months of parenting that leads to mostly positive growth. So I cannot help thinking that the Mommy Brain is ultimately a good thing,” Dr. Kim says.