• Posted March 6, 2025

Brain Changes May Help Explain Postpartum Depression

Subtle changes in the brain during pregnancy may help explain why some women develop postpartum depression.

A study published March 5 in Science Advances found that women with signs of depression after childbirth had increased volume in two brain areas involved in emotion and stress: the amygdala and the hippocampus.

“This is really the first step in trying to understand how does the brain change in people who have a normal course of pregnancy and then those who experience perinatal depression, and what can we do about it,” Dr. Sheila Shanmugan told The New York Times. Shanmugan, who co-wrote a related article published in the same journal, is an assistant professor of psychiatry at the University of Pennsylvania.

The research appears to be the first to directly link specific brain changes during pregnancy to postpartum depression, a condition that affects about 1 in 7 women.

Researchers tracked 88 women who were pregnant for the first time and who had no history of depression or other mental health disorders. 

They underwent brain scans during the third trimester and again about a month after giving birth. They were compared to a control group of 30 women who were not pregnant.

The scans revealed that women with moderate or severe postpartum depression symptoms had larger amygdalae, a brain region critical to processing emotions and stress.

Women who described their childbirth experience as stressful or difficult also had larger hippocampi, a brain region that helps regulate emotions.

“It might be that those persons whose amygdala is more susceptible to change are also at higher risk of suffering postpartum depression,” said senior study author Susana Carmona, a neuroscientist who leads the Neuromaternal Laboratory at the Gregorio Marañón Health Research Institute in Madrid. 

“It can also be the other way around,” she told The Times, “that somehow these depression symptoms produce an increase in the amygdala volume.”

What's more, the researchers linked stressful childbirth experiences, even if the delivery itself was medically uncomplicated, to more significant changes in the brain. 

Factors such as feeling dismissed by hospital staff contributed to this theory.

Previous studies have shown that “a negative birth experience is associated with increases in depression scores,” Carmona added.

Laura Pritschet is a postdoctoral scholar in psychiatry at the University of Pennsylvania who co-authored the accompanying article with Shanmugan.

She told The Times the findings point the way to further research “trying to figure out which areas of the brain are changing the most in relation to a variety of outcomes after you give birth, such as mood, anxiety, depression.”

“If we routinely show certain brain areas are implicated, what do we do? How can we intervene early?” Pritschet added. “What is the normal amount of change? Why might that area be vulnerable? Lots of interesting questions to ask next.”

More information

The Mayo Clinic has more on postpartum depression.

SOURCE: The New York Times, March 5, 2025