During pregnancy, the body goes through a remarkable transformation, so it should come as no surprise that the brain does too. However, the extent of these changes has not been well studied.
Now, in the first study of its kind, scientists have documented the remodeling of the human brain during pregnancy.
Previous studies have compared snapshots of the brain before and after pregnancy and concluded that pregnancy reduces the volume of gray matter in parts of the brain involved in social cognition. Others have demonstrated how key pregnancy hormones directly switch genes on and off in our brain cells, resulting in this structural remodeling. But now, for the first time, scientists have mapped the human brain over the course of pregnancy and witnessed the different stages of this metamorphosis.
“We wanted to look at the trajectory of brain changes specifically within the gestational window,” said Laura Pritschet, the study’s first author and a current postdoc at the University of Pennsylvania, in a statement.
The study, published in the journal Nature Neuroscience, followed one first-time mother and scanned her brain every few weeks, from before her pregnancy all the way through to two years postpartum.
The data revealed significant changes in brain structure across gestation. In particular, they saw a marked decrease in cortical gray matter volume—the wrinkly part on the outside of the brain that is responsible for information processing—as hormone production rose during pregnancy.
This might sound like a bad thing, but the researchers emphasized that the change can indicate “fine-tuning” of the brain circuitry, not unlike what happens during adolescence.
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The team also noticed a prominent increase in white matter, which is located deeper in the brain and is involved in connecting regions of the brain and facilitating their communication.
While the changes in gray matter volume persisted long after giving birth, changes in white matter were transient, peaking during the second trimester and going back to pre-pregnancy levels when the child was born.
“The maternal brain undergoes a choreographed change across gestation, and we are finally able to see it unfold,” Emily Jacobs, said one of the study’s co-authors and a professor at the University of California, Santa Barbara, in the statement.
The team hopes to use their dataset to gain new insights into conditions like postpartum depression, which affects roughly 1 in 5 women.
“There are now FDA-approved treatments for postpartum depression, but early detection remains elusive,” Pritschet said. “The more we learn about the maternal brain, the better chance we’ll have to provide relief.”
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References
Hoekzema, E., Barba-Müller, E., Pozzobon, C. et al. Pregnancy leads to long-lasting changes in human brain structure. Nat Neurosci 20, 287–296 (2017). https://doi.org/10.1038/nn.4458
Ammari, R., Monaca, F., Cao, M., Nassar, E., Wai, P., Del Grosso, N.A., Lee, M., Borak, N., Schneider-Luftman, D., & Kohl, J. (2023). Hormone-mediated neural remodeling orchestrates parenting onset during pregnancy. Science, 382(6666), 76–81. https://doi.org/10.1126/science.adi0576
Pritschet, L., Taylor, C.M., Cossio, D., Faskowitz, J., Santander, T., Handwerker, D.A., Grotzinger, H., Layher, E., Chrastil, E. R., & Jacobs, E.G. (2024). Neuroanatomical changes observed over the course of a human pregnancy. Nature Neuroscience.
