Pregnancy is a time of massive physiological upheaval that disturbs every major organ system in the body. “We’re often told, ‘don’t worry, it all resolves afterwards,’” said Liisa Galea, a behavioral neuroendocrinologist at the Center for Addiction and Mental Health. “But does it really? Or is there a long-lasting signature? I’ve always been fascinated by that.”

     Liisa Galea smiles at the camera while wearing a purple shirt and black jacket.
Liisa Galea studies how sex-specific factors such as pregnancy affect brain health and disease.
Paul Joseph

In a new study in rodents, Galea identified some of these signatures of motherhood in the brain, describing persistent differences in markers of neuroinflammation and plasticity.1

In humans, research suggests that male and female brains age differently in the context of both health and neurodegenerative disease, but the mechanisms underlying these complex sex differences are not fully understood.2,3 “We need to understand what kind of female-specific experiences might be driving increased risk or resilience,” said Galea.

To begin unraveling this mystery, Galea and her team examined cellular and molecular differences in the hippocampi of rats with zero, one, or two litters of pups.1 They found that rats with one or two litters had higher levels of post-synaptic density 95 protein—which plays a key role in the ability of neurons to alter their connections with each other—compared to non-mothers, both shortly after giving birth and in middle age. While rats without pups experienced a decline in neural stem cells with age, mothers had similar neural stem cell densities at both time points. In middle age, rats with two litters had greater densities of microglia, the brain’s immune cells, compared to rats without pups.

“I found the conclusions to be insightful,” said Jessica Bradshaw, who studies maternal brain health at the University of North Texas Health Science Center and was not involved in the study. “This highlights that even a healthy pregnancy can have short-term and long-term effects on the brain.”


  1. Duarte-Guterman P et al. Open Biol. 2023;13(11):230217.
  2. Armstrong NM et al. Neurobiol Aging. 2019;81:146-156.
  3. Laws KR et al. Curr Opin Psychiatry. 2018;31(2):133-139.