“Pregnancy brain” has long been described as a foggy, forgetful mental state that many mothers recognize—but until recently, science had little to say about it. That’s changing thanks to new research by Liz Chrastil, associate professor at the UC Irvine Center for the Neurobiology of Learning & Memory. Her personal journey into the science of motherhood offers a window into how pregnancy may reshape the brain—and opens important conversations about maternal health and dignity from a Catholic perspective.
Chrastil, who specializes in learning and memory, chose to become the subject of her own study during her 2019 pregnancy, undergoing 26 MRI scans before, during, and after childbirth. “We don’t really know what this means,” she admits, yet her work—published in Nature Neuroscience—is already prompting important questions about how pregnancy transforms a woman’s brain physically and neurologically (according to her interview with Korin Miller).
One of the clearest findings was a measurable decrease in gray matter volume, up to 4%, during pregnancy—changes that appear long-lasting. Gray matter plays a key role in memory, decision-making, and sensory processing. Though Chrastil herself reports no noticeable difference in how she thinks, these findings hint at a real, biological shift. Meanwhile, her scans also showed that white matter—the brain’s communication “highways”—actually improved in structural integrity during the second trimester before returning to baseline postpartum.
From a Catholic view, this reinforces a profound truth: motherhood is not only a spiritual and physical vocation, but one that reshapes the very core of a woman’s being. The Catechism of the Catholic Church teaches that “God himself is the author of marriage and the family,” and with it, the unique dignity of motherhood (CCC 2203). If God knits life together in the womb, it is no surprise that the womb also transforms the mother in body and mind.
Chrastil and her colleagues acknowledge that “we don’t know yet what these findings mean.” Some researchers believe the brain may be “morphing on purpose to help with maternal care,” while others suggest it may be a trade-off—resources temporarily diverted from the brain to other vital areas during pregnancy. Either way, it affirms what the Church has always held: the maternal vocation is sacrificial, mysterious, and holy.
