Since giving birth to my year-old daughter, I’ve had countless moments like this. I have trouble recalling words, forget to respond to text messages, and even missed an appointment. What I’m experiencing is often called “mommy brain”— the forgetful, foggy and scatterbrained feeling many pregnant women and new mothers experience.
But is mommy brain real?
Anecdotally, yes. Ask any new mom if she has felt the above, and she'll likely say she has — as many as 80 percent of new moms report feelings of mommy brain. Scientifically, it also appears the answer is yes: A growing body of research supports the argument that moms' brains change during pregnancy and after giving birth. A clear explanation for the phenomenon still remains somewhat elusive, however.
There are countless variables that experts say contribute to mommy brain, such as fluctuating hormones postpartum, sleep deprivation in dealing with a new baby, anxiety over new parenthood, elevated stress levels, and a general of lives that having a baby forces.
Put together, it’s only natural that changes in mental processing would occur, says Moriah Thomason, Barakett associate professor of child and adolescent psychiatry at New York University School of Medicine. When our brain needs to make space for a new priority — keeping a baby alive — remembering a grocery list takes a back seat.
“Does it mean that you literally cannot do those things that you used to do as well? Probably not,” she says. “It’s just not the most important thing for you to be accessing.”
Several small studies have come out in the past few years that support the existence of mommy brain. Abigail Tucker, author of “Mom Genes: Inside the New Science of Our Ancient Maternal Instinct,” says that a meta analysis of all these studies concluded that women experience cognitive changes like forgetfulness and trouble with verbal recall in the immediate months and years after giving birth.
Many Americans expect women to be on the ball again just six weeks after giving birth, Tucker says. They chalk mommy brain up to sleep deprivation when that’s really just the tip of the iceberg. In reality, our brains are undergoing changes that extend well beyond six weeks.
“When women talk about this idea of mommy brain or mommy fog, maybe we ought to believe them and not say, ‘Oh, you’re just making this up,’ ” Tucker says. “There really is something there.”
Some neuroscience research also supports the idea that women’s brains physically change after giving birth. A 2017 study published in Nature Neuroscience found there is a decrease in gray matter in the area of moms’ brains that is responsible for social cognition. This shrinkage was still present two years after childbirth, suggesting that having a baby may lead to permanent structural changes in the brain.
But experts aren’t sure what this reduction in gray matter means. The study subjects with the largest gray matter shrinkage also tended to have the highest levels of maternal bonding. Some experts believe the gray matter shrinkage is part of a neural pruning effect in which moms’ brains are essentially rewiring to adapt to their new role as parents, a process that is also seen during adolescence — a time of significant brain development and maturation.
“Brain shrinkage sounds sad and depressing, but people have argued that this drop in volume in certain parts of the mom brain might not actually mean these brain parts are getting worse,” Tucker says. “There could be a neural pruning effect that goes on where these circuits are getting weeded out and being made leaner and leaner.”
Alternatively, some research suggests new mothers’ brains don’t shrink but rather grow.
Pilyoung Kim, a developmental psychologist at the University of Denver who studies how mothers’ brains change during the postpartum period, says her research has shown increases in some brain areas including the prefrontal cortex, which controls planning, learning and emotional regulation, in the parietal lobe, which is related to empathy, and in the temporal lobe, which helps moms understand babies’ cues.
That research squares with some of what I have encountered as a new mom. Although I’ve struggled to recall simple words or remember to reply to text messages, I’ve also noticed that I can easily distinguish between my daughter’s four different cries. I also feel incredibly alert and hypervigilant at all times — even when I’m sleep deprived.
“You’re more focused on subtle things that you might not have noticed before,” Tucker says, adding that research has shown pregnant women and new moms often are better than nonpregnant women at everything from distinguishing between subtle color differences to riding out stressful events like earthquakes. “The cognitive advantages [new moms] have are something like a super power.”
One small 2020 study suggests that brain fog is overstated. Study co-author Valerie Tucker Miller, an anthropology doctoral candidate at Purdue University, looked at 60 moms who were at least one year postpartum vs. 70 non-mothers, and found that the new moms’ reaction times (a stand-in for attention) were as good if not better than the non-mothers’ — despite the new mothers being on average 10 years older.
“Moms were not as distracted by those outside, incongruent items,” Miller says in a news release about the study. “It makes perfect sense that moms who have brought children into this world have more stimuli that needs to be processed to keep themselves and other humans alive, and then to continue with all the other tasks that were required before the children.”
When my daughter was just a few months old, I told my husband about my newfound absent-mindedness. He said he often felt the same. He chalked it up to sleep deprivation, both from countless night wakings and his long hours as a medical resident. But was it all just sleep deprivation, or is there a daddy brain, too?
Dads’ brains were also looked at in the 2017 gray matter study, and the authors found they did not have the same changes as new mothers. Kim has also studied dads’ brains, and she says that although dads experience structural changes in the brain during the first few months postpartum, their changes are not as significant as the ones moms experience.
Still, dads do undergo a transformation of sorts. One 2014 study looked at first-time mothers, heterosexual fathers and homosexual fathers, all of whom were the primary caregivers. The researchers found that brain activity in areas of vigilance, reward, social understanding, cognitive empathy and motivation were consistent across all three parent types.
There’s still no “slam dunk” when it comes to understanding the mommy brain, Tucker says, since there’s not enough science yet on the topic.
“What is clear is that there is measurable change and that mothers are organisms in flux,” she says. “I think that insight is enough to startle people and strongly imply that we structure social policies and create a set of cues for moms that will allow their brains to go through this metamorphosis.”