When Susana Carmona became a mother more than a decade ago, she struggled to reconcile her experience with the expectation that she would enjoy every aspect of caring for her daughter. The neuroscientist, who lives in Spain, told CTVNews.ca Thursday she found the reality of motherhood didn’t always match the “romantic narrative” spun for new mothers, particularly the assumption that wanting to care for a baby was the same as enjoying it. Around the same time, Carmona started to research the neuroscientific impact of pregnancy on the brain, a topic she said hadn’t been explored much then. She said she learned that a region in a mother’s brain perceives any stimuli associated with the baby as a “motivator,” which prompts a mother to take care of the baby. But the motivation doesn’t “immediately translate into pleasure,” she added. “To me, it was very obvious that motherhood many time entails wanting (to care for the baby) but not always liking (it).” Carmona said the findings, comforted her on her own experience as a new mother. Her book, A Mother’s Brain: The New Science of the Neuro-Maternal Revolution, released earlier this month, dispelled stereotypes about what a woman’s brain goes through during pregnancy. Carmona said that experts once assumed that pregnancy could cause cognitive decline and that a woman, post-labour, would be able to return to normal in a relatively short period of time If anything, Carmona said changes in the brain during pregnancy may be more dramatic than those affecting children during adolescence, a phase typically defined as the most pronounced in brain development over an individual’s life. “Those are the most pronounced changes I have seen in my career,” she said. Brain architecture changes According to Carmona, pregnancy, quite literally, changes the organ’s structure. Researchers found that the volume of grey matter tissue found in the brain’s cortex - the organ’s outer layer - decreased during pregnancy. While the tissue did increase during the postpartum period, it did not go back to pre-conception levels. It also strengthened parts of the brain’s white matter architecture, which functions as a “communication highway” within the brain, according to a 2026 study published in the U.S. National Library of Medicine. Previously, the decline in grey matter was thought of as “something bad,” Carmona said, with some experts assuming it to be the cause of cognitive decline in pregnancy women. Most changes in the brain appear to be confined to a set of brain regions known as the “default mode network,” she added, which acts as an individual’s “internal voice” and contributes to their ability to empathize. At first, researchers thought that the changes might help the mother better understand her baby. However, as her team collected more data on the topic, Carmona said the link between the changes in a mother’s cognitive functioning and behaviour remains inconclusive. “But we know that they correlate with maternal well-being and mother-infant bonding,” she said. “ The more that the brain changes, the better the mother feels, and the easier it is for her to bond with the baby.” Researchers also found that some cells containing the baby’s DNA settle directly into the mother’s brain and organs, and could remain there for the rest of her life. However, Carmona saidit’s unclear what impact that has on the mother’s neurobiology. Dispelling the ‘mommy brain’ Carmona said that many people believe that once a woman has given birth, she can return to how she functioned prior to pregnancy, maybe in as little as two weeks. But she warned the changes the brain goes through during pregnancy are “long-lasting” and could “last forever.” Pregnancy is typically associated with “mommy brain,” a common colloquial applied to the mental fog and forgetfulness many women experience during the nine months. “We are all born with this idea that once you become a mother, your mental resources, your memory, your attention will decline,” she said. But according to Carmona, the data told a different story. Biologically, the gestation and postpartum periods are “metabolically demanding,” Carmona said, which can mean a tired body and brain. “(It) doesn’t matter if you’re a mother or a CEO ... you’re going to notice that your memory or attention is going to decline, because sleeping cleans your brain too.” Mothers are especially sensitive to baby stimuli in the first weeks post-labour. “Mothers who breastfeed also feel like, just by hearing the small sound of a baby, all the body reacts,” she said. “(T)hat leaves a little bit less to the other things that our body does not consider as important during the postpartum period.” However, Carmona said in the long term, motherhood can protect against aging and cognitive decline. Researchers have found that long-time mothers “show signs of what we call a younger-looking brain,” she said. “Women who have been mothers decades ago show signs of what we call a younger-looking brain,” she said. “It’s like raising a child is constantly doing sudokus, right? You have to be constantly thinking and planning, and it’s exercising your brain for the long term.” The hormonal and immune changes during gestation may also partly protect women from entering their perimenopausal period with inflammation, she said. Medical knowledge gap Carmona said she can’t recall her doctors initiating a conversation on the cognitive impact of her pregnancy. “I don’t even have an anecdote because that was not even something to discuss,” she said. While she relied on perinatal psychologists for support, she expressed concern that some might rely on untrustworthy sources for advice. In the past, medical advice focused on the physiological care of the unborn child and mother - or “from the neck down,” as Carmona put it. “If you look at medical textbooks, you open the typical illustration about the physiological changes of pregnancy,” she said. “The illustration is usually the body of a woman, but only from the neck down.” The illustration choice “reflects what we know and what we don’t know,” she added. Past advice shared with pregnant women was based on non-human animal studies and psychological theories. She recalled a past conversation with a nurse during a blood test appointment. The nurse said that pregnancy hormones kill brain cells. “Since there’s no data, (medical experts) cannot get anything wrong,” she said. “It’s just that they are not based their assumptions on scientific research, right?” Many questions still unanswered Carmona hopes the research will ultimately help experts understand how to prevent and treat prenatal medical health disorders. That entails connecting the findings to existing knowledge of a pregnancy’s physiological impact on the body. Carmona is also exploring the impact of pregnancy in other types of parenthood, including fathers and adoptive mothers. She hopes the book will encourage mothers to see what’s “going on” with a “curiosity lens” and help others better understand the neuroscientific impact of pregnancy and motherhood.
