Researchers are investigating the significant changes that take place in the brain during pregnancy.
Pregnancy is a pivotal time that brings quick physiological changes in a person as they prepare for motherhood. While this is widely recognized, the impacts of the extensive hormonal changes during pregnancy on the brain have remained somewhat unclear. A research team led by Professor Emily Jacobs at UC Santa Barbara has made strides in this area, creating the first comprehensive map of a human brain throughout pregnancy.
“Our goal was to examine how the brain changes specifically during the pregnancy period,” explained Laura Pritschet, the lead author of a newly published paper in Nature Neuroscience. Past research has only looked at brain changes before and after pregnancy, she noted, and this study is unique as it tracks the brain during the transformative stages of pregnancy.
By focusing on one first-time mother, the researchers performed brain scans every few weeks, beginning before she became pregnant and continuing for two years after giving birth. This data was gathered in partnership with Elizabeth Chrastil’s team at UC Irvine, revealing shifts in both gray and white matter in the brain across the duration of pregnancy. These findings indicate that even in adulthood, the brain can exhibit remarkable neuroplasticity.
Utilizing advanced imaging techniques allowed them to capture the ongoing reorganization of the brain in great detail. This method enhances previous studies that compared women’s brains before and after pregnancy. The authors remarked, “our aim was to bridge the gap and comprehend the neurobiological changes that occur during the pregnancy itself.”
Decrease in gray matter, increase in white matter
The most significant alterations they observed during the brain scans were a reduction in the volume of cortical gray matter, which is the wrinkled outer layer of the brain. This gray matter volume diminished as hormonal production increased during pregnancy. However, the researchers emphasized that a decrease in gray matter is not necessarily negative; it may signify a “fine-tuning” of brain circuits, similar to changes that young adults undergo during puberty when their brains specialize. Thus, pregnancy could represent another phase of cortical refinement.
“Laura Pritschet and her team conducted an outstanding range of analyses that revealed new insights into the capabilities of the human brain and its remarkable plasticity during adulthood,” Jacobs remarked.
Less apparent but equally noteworthy was the notable increase in white matter, which is situated deeper within the brain and generally aids in communication between different brain areas. While the gray matter volume reduction continued for an extended period after childbirth, the increase in white matter was temporary, peaking during the second trimester and returning to pre-pregnancy levels around the time of delivery. This phenomenon had not been previously observed in conventional before-and-after studies, underscoring just how quickly the brain can adapt.
“The maternal brain undergoes a coordinated transformation throughout pregnancy, and we are finally able to observe this process,” Jacobs stated. These changes imply that the adult brain can experience prolonged neuroplasticity, which may support the behavioral adjustments required for parenting.
“Eighty-five percent of women experience pregnancy at least once in their lives, with around 140 million women becoming pregnant each year,” said Pritschet, who aims to “challenge the notion” that women are fragile during pregnancy. She asserted that understanding the neuroscience of pregnancy is an essential area of research, as findings in this field can “enhance our overall knowledge of the human brain and its aging.”
The open-access dataset, available online, is intended to spark further research into whether the intensity or speed of these brain changes could provide insights into a woman’s risk of postpartum depression, which affects about one in five women. “While there are now FDA-approved treatments for postpartum depression,” Pritschet noted, “early detection still remains elusive. The more we understand the maternal brain, the better we can support those in need.”
This is precisely what the authors intend to achieve. With backing from the Ann S. Bowers Women’s Brain Health Initiative, led by Jacobs, the team is expanding on these initial findings through the Maternal Brain Project. More women and their partners are being included in this research at UC Santa Barbara, UC Irvine, and through an international collaboration with researchers in Spain.
“Experts in neuroscience, reproductive immunology, proteomics, and artificial intelligence are working together to deepen our understanding of the maternal brain,” Jacobs concluded. “Together, we have a chance to address some of the most urgent yet least understood challenges in women’s health.”
