Roy Suryo
The common stereotype of "baby brain" – a period of forgetfulness and reduced cognitive function often attributed to pregnant women – is being challenged by groundbreaking new research. A comprehensive study, the largest of its kind to date, suggests that pregnancy triggers significant structural changes in the brain, a transformation that may actually be an adaptive mechanism to prepare expectant mothers for the demands of childcare. The findings indicate a reduction in grey matter, the crucial brain tissue responsible for processing information, emotions, and empathy, by an average of nearly 5% during pregnancy. Far from being a sign of decline, scientists propose these neurological shifts are beneficial, enhancing a mother’s ability to bond with and care for her newborn.
Tania Esparza, a participant in the study and a new mother, voiced her support for the research, expressing her frustration with the infantilization of pregnant women. "Rather than becoming dumber, we are becoming more specialised for the job," she stated, emphasizing that the changes are a form of adaptation, not degradation. The BBC was granted exclusive access to the "Be Mother" project, which involved scanning the brains of 127 pregnant women at various stages – before, during, and after pregnancy – and comparing these to scans of non-pregnant women.
A key discovery from the study is the correlation between the extent of these brain changes and a woman’s reported ability to relate to and bond with her baby. Professor Susana Carmona, from the Gregorio Marañón Health Research Institute in Madrid and a co-lead of the study, explained that these structural alterations might represent the brain "rewiring" or remodelling itself to "prime it for motherhood." She uses the analogy of pruning a tree: "Some of the branches are cut to make it grow more efficiently." This perspective suggests that a reduction in certain neural pathways can lead to more focused and effective neural processing related to maternal care.
Carmona further posits that just as pregnancy induces physical changes in other organs, such as the heart and lungs, it is logical that the brain would also undergo significant alterations. She argues that the focus should shift from potential memory deficits to the acquisition of a whole new set of skills required for new motherhood. The study underscores the need for more research into this pivotal period in women’s lives, acknowledging that current investigations into the pregnant brain are relatively scarce.
The "Be Mother" project involved pregnant women in Madrid and Barcelona undergoing five MRI scans each, alongside hormone tests and questionnaires detailing their emotional changes. To differentiate between the biological effects of pregnancy and the psychological aspects of becoming a mother, the researchers also scanned the brains of 52 non-pregnant women, including 20 who were partners of the pregnant participants. This comparison helped to isolate whether the observed brain changes were a direct result of pregnancy itself or related to the broader experience of motherhood. Carmona emphasized that parenting encompasses more than just pregnancy, and that "You can be many types of parents, and you don’t need to be pregnant to be a good one."
The study, published in the prestigious journal Nature Communications, provides compelling evidence for structural brain changes during pregnancy. While not specifically designed to investigate the anecdotal "baby brain" phenomenon, it offers significant insights. The pregnant women experienced an average reduction of nearly 5% in grey matter volume, which partially, but not fully, returned by six months postpartum. In contrast, the control group of non-pregnant women showed only minor, stable fluctuations in grey matter volume. Carmona noted that these significant dips in grey matter were unexpected, given the usual small variations in brain volume over time.
One of the most notable areas exhibiting persistent changes in grey matter was the default mode network, a brain region intrinsically linked to self-perception, empathy, and altruism. This suggests that the brain restructuring might be directly enhancing the very traits crucial for nurturing and bonding with an infant. Carmona theorizes that this transformation could be attributed to the pruning of nerve networks, alterations in blood vessels, and changes in the cells that support nerve function, all contributing to a positive rewiring of the brain for motherhood. This process bears similarities to observed brain changes during adolescence, where a refining and pruning of neural networks occurs as the brain matures from childhood to adulthood.
Furthermore, decades of animal research have consistently demonstrated profound brain alterations during pregnancy in various mammalian species. Studies in mice, for instance, have indicated that pregnancy hormones directly influence specific nerve cells in the brain, activating parental behaviors. In the absence of these hormonal influences, mice often exhibit neglect towards their offspring.
Carmona’s team has identified hormones as a potential key player in this process for humans. Their research revealed that rising estrogen levels in some women tracked closely with the observed reduction in grey matter. The study, funded by the European Research Council, aims to build a detailed neurological map of the pregnant brain and chart its transformation into motherhood. Carmona believes this research could have significant implications for understanding and addressing issues such as postpartum depression.
Professor Liz Chrastil from the University of California echoed the importance of Carmona’s work, stating that it could "help with attachment between caregivers and infants, and to find better ways to provide support and recovery for new moms." While this particular study did not directly examine memory function, Carmona’s prior research in 2016 on a smaller group of pregnant women found no significant changes in memory, although evidence from other studies remains mixed.
Carmona acknowledges that some women do experience memory lapses and emphasizes that her work does not aim to diminish these individual experiences. She attributes these feelings to the immense metabolic demands of pregnancy, which can lead to reduced energy, sleep deprivation, and decreased alertness. Ana Mudrinic, a new mother from London, shared her own experience of forgetfulness during pregnancy, recalling a moment where she "simply couldn’t remember [her boss’s] name" when intending to send an email.
However, Mudrinic also noted a positive shift in her resilience at work. "I don’t get emotionally impacted by stress as I used to before, because all of a sudden, some things are not as important as they used to be," she explained. She added, "I might forget to do things that aren’t related to [my baby], but I’ve learnt to prioritise her." This sentiment reflects a reordering of priorities, a potential byproduct of the brain’s adaptation.
Tania Esparza stated that Carmona’s earlier research had influenced her decision to become a mother, "I was excited by the idea that I could meet a new, different version of myself." She advocates for a reevaluation of how mothers are perceived and treated, suggesting that they are undergoing a profound transformation and should be viewed as emerging from a cocoon into something new and different.
Additional reporting by Catherine Snowdon.
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