A woman’s body undergoes extensive changes throughout pregnancy, including hormonal, cardiovascular, respiratory, gastrointestinal, and urine changes. A new study also shows that the brain changes significantly, with some alterations being temporary and others lasting longer.
On Monday, researchers said that, using data from 26 scans, which began three weeks before conception and continued for nine months of pregnancy and two years after delivery, they had finally traced the changes that occur when a woman’s brain reorganizes in response to pregnancy.
The research revealed both an improvement in the microstructural integrity of the white matter found deeper in the brain and a broad drop in the volume of cortical gray matter, the wrinkled region that makes up the brain’s outermost layer. Estradiol and progesterone levels increased in tandem with both modifications.
The cell bodies of the brain’s nerve cells make up gray matter. The bundles of axons, or long, thin fibers, from nerve cells that carry impulses across large distances throughout the brain, make up the white matter.
The first of its kind, the study focused on Elizabeth Chrastil, a cognitive neuroscientist and study co-author from the University of California, Irvine. Chrastil was a first-time mother who gave birth to a healthy boy who is now 4-1/2 years old. Chrastil is 43 now, while he was 38 throughout the study.
Since the study’s conclusion, the researchers have seen the similar pattern in many other pregnant women who had their brains scanned as part of the Maternal Brain Project, an ongoing research project. They want to push that figure up into the hundreds.
“It’s pretty shocking that in 2024 we have hardly any information about what happens in the brain during pregnancy. This (research) paper opens up more questions than it answers, and we are just scratching the surface of these questions,” Chrastil continued.
About 80% of the brain regions examined in the scans had reduced gray matter, with an average loss of about 4%. The volume did not return to pre-pregnancy levels despite a slight rebound after delivery. White matter microstructural integrity, a measure of the strength and quality of the connections between different brain regions, increased by almost 10% in the scans as well. This rise peaked late in the second and early in the third trimester and returned to pre-pregnancy status after delivery.
Neuroscientist Emily Jacobs of the University of California, Santa Barbara, the study’s principal author, stated, “The maternal brain undergoes a choreographed change across gestation, and we are finally able to observe the process in real time,” The study was published in the journal Nature Neuroscience.
“Previous studies had taken snapshots of the brain before and after pregnancy. But we’ve never witnessed the brain in the midst of this metamorphosis,” Jacobs continued.
It’s unclear whether losing gray matter has negative effects, according to the researchers.
Lead author Laura Pritschet of the University of Pennsylvania noted, “This change could indicate a fine-tuning of brain circuits, not unlike what happens to all young adults as they transition through puberty and their brain becomes more specialized. Some changes we observed could also be a response to the high physiological demands of pregnancy itself, showcasing just how adaptive the brain can be,”
In the future, the researchers intend to investigate how variations in these alterations may aid in the prediction of phenomena like postpartum depression and the potential brain effects of preeclampsia, a dangerous blood pressure disorder that may arise during pregnancy.
Chrastil claimed she felt no different during the research and was unaware of the evidence demonstrating her brain changes.
Lead author Laura Pritschet of the University of Pennsylvania noted, “This change could indicate a fine-tuning of brain circuits, not unlike what happens to all young adults as they transition through puberty and their brain becomes more specialized. Some changes we observed could also be a response to the high physiological demands of pregnancy itself, showcasing just how adaptive the brain can be,”
In the future, the researchers intend to investigate how variations in these alterations may aid in the prediction of phenomena like postpartum depression and the potential brain effects of preeclampsia, a dangerous blood pressure disorder that may arise during pregnancy.
Chrastil claimed she felt no different during the research and was unaware of the evidence demonstrating her brain changes.
