Pregnancy Changes Mothers’ Brains. These Recent Discoveries Are Showing Us How

“Baby brain” isn’t the deficit it’s stereotyped to be, research suggests. Neural adaptations during pregnancy can prime soon-to-be-moms to become more attuned to their children and enhance social cognition

Daliah Singer

May 8, 2026 8:23 p.m.

I’d looked in every drawer, through every basket and on every countertop. I’d emptied out the contents of my purse and searched my coat pockets. Nothing. My husband’s keys had disappeared. It wasn’t until I walked outside 30 minutes later that I found them, dangling from the lock on our front door. That sort of absent-mindedness was unusual for me—and incredibly frustrating. Since becoming pregnant with my first child in early 2024, my mind has felt different. I commonly lose my train of thought and grasp for words on the tip of my tongue. Deep, critical thinking can be exhausting.

None of this is unusual. Up to 80 percent of pregnant women report memory issues and, for many, those struggles continue into the early postpartum period. Often referred to as “mommy brain” or “baby brain,” these feelings of brain fog, forgetfulness and trouble concentrating are generally portrayed and experienced as deficits. But a body of recent research is revealing what actually happens inside women’s heads during this period: Their brains’ structures and functions are profoundly changing—and that remodeling, the studies suggest, is largely positive.

Throughout pregnancy, the body is flooded with hormones—namely, estrogen and progesterone—that support fetal development and create a stable environment for the baby. But these fluctuations, among other physiological shifts, also have implications for the mind. Mothers’ brains look different, and the changes facilitate their connection to and understanding of their infants.

“We women were right,” says Susana Carmona, a neuroscientist and director of the neuromaternal lab at Hospital Gregorio Marañón in Madrid. “We knew that something happens to our brains, or the way we perceive the world and the way we feel. Now, we have neuroimaging data that very powerfully demonstrates that motherhood changes you completely.”

A rewiring of the brain

Neuroscientists are learning a lot from mothers. Among the most important recent lessons: The brain doesn’t stop growing and changing after adolescence. Rather, neuroplasticity, or the brain’s ability to reorganize itself, continues well into adulthood.

Track the brain of a pregnant woman and you’ll note significant changes to its structure throughout the trimesters, including a decrease in the volume of gray matter, which forms the outer layer of the brain and facilitates information processing. There’s a drop in cortical volume, which is associated with cognitive ability, memory and sensory processing. You may also see suppressed production of new neurons in the hippocampus, which is linked to learning and memory.

Losing anything in the anatomy of our brains may sound alarming, but researchers are quick to note that this is a rewiring, not a shrinking. “I think the best analogy is to think of it like adolescence, where the brain is undergoing this transformation, also driven by these massive endocrine changes, and once it’s changed, that’s the point,” says Emily Jacobs, a neuroscientist at the University of California, Santa Barbara, and director of the Ann S. Bowers Women’s Brain Health Initiative. “It can take on these new things, new behaviors that it didn’t experience before.”

Jacobs directed a 2024 study in which her team took brain scans and blood samples from a fellow neurobiologist from preconception through two years postpartum. The results highlighted the “highly dynamic changes that unfold in a human brain across pregnancy,” per the paper, including the reduction in gray matter and cortical volume. They also observed enhanced microstructural integrity of white matter, including in the tracts that relate to communication between the brain’s emotional and visual processing areas. Another 20 women have since gone through the protocol, Jacobs says, and those results are expected to be published soon.

These brain tweaks may have a functional purpose. A partial rebounding of gray matter volume in the first months of motherhood is believed to facilitate mother-infant bonding. In 2025, a paper published by Carmona and others showed that women who had the greatest degree of brain remodeling also had the highest infant attachment scores. 

Soon-to-be mothers’ abilities to read facial expressions, particularly if the faces are fearful, angry or sad, may be enhanced later in pregnancy. Regions of the Default Mode Network, which informs how we think about ourselves and our social cognition, have also shown increased connectivity during and after pregnancy. In humans and rats, there’s some evidence of improved memory postpartum, and in the former, brains actually appear younger after childbirth than they did preconception.

“We’ve gone as far as talking about parenthood as being enrichment and cognitive enrichment—that you’re actually showing the potential for growth. If you’re showing that there’s efficiency through the reorganization that’s happening … you’re actually showing a positive gain from parenthood,” says Helena Rutherford, a psychologist at Yale University and director of the Before and After Baby Lab. These benefits are rarely discussed, she adds. “It’s always a negative.”

These impacts also appear to be long-lasting, says Elseline Hoekzema, head of the Pregnancy Brain Lab at the Amsterdam University Medical Center. Some adaptations, such as the reduced gray matter volume, can last six years, if not longer; the functional modifications, including the operation of the Default Mode Network, rebound to near preconception levels within the first postpartum year. (Those who breastfeed longer may maintain those functional alterations for an extended period.)

In second pregnancies, these adaptations are fine-tuned, with the brain networks that direct attention and respond to sensory cues seeing more substantial changes, according to a study published by Hoekzema and others in February.

“We have seen that the observed changes are incredibly consistent across different women,” Hoekzema says. Longitudinal studies tracking women throughout pregnancy in the United States, Spain, the Netherlands and Germany have shown similar results to Jacobs’ work as well, indicating that the brain changes are widespread.

What’s also common: the confusion pregnant women and new mothers may feel as these adjustments occur. “Her brain is going through a process of change,” Hoekzema adds, “but this will normalize, and it seems to be for a good purpose.”

The role of hormones

Chelsea Conaboy thought she was prepared to have her first child in 2015. She read books, took classes, toured the hospital where she’d be delivering and felt financially ready for a kid. She and her husband “checked all of those boxes,” she says, “and I still felt really blindsided by the experience of new motherhood.”

Worry and anxiety were regular companions for the health and science journalist in the early months—a common response to a significant life change and the boost in cortisol the pregnant body produces to support the fetus. While hormones are a significant point of conversation throughout pregnancy as doctors track the growing baby, OB/GYNs likely won’t mention that those same hormones also play a role in significant brain modifications for the mom.

“Those [brain] changes can cause anxiety, but they also are these massive, lifelong changes that we don’t talk much about,” says Conaboy, author of Mother Brain: How Neuroscience Is Rewriting the Story of Parenthood. “That wasn’t part of my prenatal education at all,” she adds. “Why weren’t we giving expectant parents this information to help them understand themselves and this transition in the way their brain works?”

Pregnancy sparks a 100- to 1,000-fold increase in hormone production, which leads to changes across the whole body, including increased oxygen consumption, metabolism and blood volume, as well as shifts in the nervous and immune systems. These chemical messengers are also involved in the brain’s reorganization.

“Hormones are essentially the sculptor,” Jacobs says. “They’re sculpting the brain, allowing it to sort of become super-efficient, super attuned to this new time of life.” A 2020 report by Jacobs demonstrated that the brain circuits that facilitate memory and mind-wandering are enhanced when estrogen levels peak during the menstrual cycle, which might shed light on pregnancy. “The insights that we can glean from understanding how the brain responds to a smaller modulation like the menstrual cycle can definitely presage the things we might see across pregnancy,” Jacobs says. “The two are yoked.”

Much of the research into these hormone-fueled adaptations in humans has only occurred in the last decade or two, though animal models have shown these trends for much longer. They suggest that gestational hormones generate caregiving behaviors and facilitate stronger connections between mother and baby. A 2023 study, for example, showed a remodeling of hypothalamic neurons in pregnant mice that prompted the development of maternal behaviors, “in anticipation of future behavioral need.” Another, published last year, found that the pre-pregnancy estrous cycle in female mice was responsible for molding the structure and function of neurons in the hippocampus.

Taken together, the work shows just how much pregnancy changes the brain. “It is one of the biggest effects I have ever seen in neuroscience,” Jacobs says, “this magnitude of change over such a short period.”

Many questions remain

The brain fog and memory struggles I experienced postpartum may not be direct results of these brain changes. Research has not yet answered the questions of whether, and how, the brain’s alterations during pregnancy are correlated with behavior or with women’s reported declines in cognitive performance. “As much as we might see these imaging differences, what do they actually mean on a behavior level? We don’t know,” says Sasha Davies, a psychologist at the Cairnmillar Institute in Australia. “And when we do look at the cognitive functioning, we don’t know really what the day-to-day impact is, if any.”

Some of those issues may be the result of major lifestyle changes during this time, like a lack of sleep and the mental load that accompanies pregnancy and parenting.

Researchers are conducting longitudinal studies to better understand these and other questions, including what the potential effects of age, race and other demographics might be. Much of the published work in this area has had a dearth of racial diversity, researchers wrote last year.

Studying “mommy brain” also has a potentially lifesaving upshot: It might shed light on postpartum depression. The condition affects one in eight women in the U.S., but experts estimate that around half of all mothers experiencing symptoms are undiagnosed. The U.S. maintains the highest maternal mortality rate among developed nations, with suicide being one of the country’s leading causes of postpartum deaths. “If parents are struggling, there’s going to be an impact then on the developing child, too. So we’re propagating risk across generations, when we could be doing a lot more to support that,” says Rutherford, the Yale psychologist. Recent research, she adds, suggests the transition to parenthood is “a period we should be talking more about.”

As labs across the world strengthen their databases on pregnancy-related changes in the brain, hormones and more, it could allow them to predict the onset of postpartum depression and identify other markers of maternal well-being.

“There’s an urgency,” to this work, neuroscientist Carmona says. “It’s not something that affects the economy of this person. It also affects the development of the baby and the whole system and the whole family.”