A study from scientists in Madrid has shed new light on what happens in the brains of pregnant women who experience postpartum depression, which affects about one in every seven mothers who give birth.
Researchers scanned the brains of dozens of women in the weeks before and after childbirth and found that two brain areas involved in the processing and control of emotions increased in size in those who developed symptoms of postpartum depression.
The results, published in the journal Science Advances, constitute some of the first evidence that postpartum depression is associated with changes in the brain during pregnancy, reports The New York Times.
The researchers found that women with symptoms of depression in the first month after giving birth also had increases in the volume of their amygdala, a brain area that plays a key role in emotional processing.
Women who rated their childbirth experience as difficult or stressful – a perception often associated with postpartum depression – also showed increases in the volume of the hippocampus, a brain area that helps regulate emotions.
“This is really the first step in trying to understand how the brain changes in people who have a normal course of pregnancy and then those who experience perinatal depression, and what can we do about it,” said Dr Sheila Shanmugan, an assistant professor of psychiatry, obstetrics-gynaecology and radiology at the University of Pennsylvania, who was not involved in the study.
“The big takeaways are about how there are these profound brain changes during pregnancy and how now we’re seeing it in depression circuitry specifically,” she said.
The Spanish study was conducted by a team that has led efforts to document the effects of pregnancy on the brain. It is part of a growing body of research that has found that certain brain networks, especially those involved in social and emotional processing, shrink during pregnancy, possibly undergoing a fine-tuning process in preparation for parenting.
Such changes correspond with surges in pregnancy hormones, especially oestrogen, and some last at least two years after childbirth, researchers have found.
The latest study appears to be the first to scan and compare brain areas during pregnancy and after childbirth and link the changes to postpartum depression, said Elseline Hoekzema, a neuroscientist who heads the Pregnancy and the Brain Lab at Amsterdam University Medical Centre and was not involved in the study.
The study authors and other researchers said it was not clear whether the increased volume in the amygdala and hippocampus drove depressive symptoms and perceptions of stress during childbirth or whether the brain changes were occurring in response to the symptoms and stressors.
It was also unclear from the brain scans why some women seemed to be more vulnerable to these symptoms than others.
“It might be that those women whose amygdala is more susceptible to change are also at higher risk of suffering postpartum depression,” said the study’s senior author, Susana Carmona, a neuroscientist who leads the Neuromaternal Laboratory at the Instituto de Investigación Sanitaria Gregorio Marañón in Madrid. “It can also be the other way around,” she said, “that somehow these depression symptoms produce an increase in the amygdala volume.”
The researchers studied 88 pregnant women who had not previously given birth and who did not have previous histories of depression or other neuropsychiatric conditions.
For a control group, they also looked at 30 women who were not pregnant. The pregnant women underwent brain scans during their third trimester and about a month after they gave birth.
The women completed standard questionnaires to assess whether they had symptoms of postpartum depression. After childbirth, 15 of them showed moderate symptoms of depression and another 13 showed symptoms of depression serious enough to warrant seeking medical help, Carmona said.
The women also completed questionnaires about whether they perceived their childbirth experience as difficult. Previous studies have shown that “a negative birth experience is associated with increases in depression scores”, Carmona said.
She added that difficult childbirth experiences were not necessarily medically challenging deliveries, but could be uncomplicated deliveries that the women perceived as stressful because of factors like rude hospital staff.
Laura Pritschet, a postdoctoral scholar in psychiatry at the University of Pennsylvania who was not involved in the study, called the results “really fascinating”, saying they 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”.
Pritschet, who wrote an article with Shanmugan in the same issue of the journal that advocates for research to determine individualised brain signatures of perinatal depression, said the findings help identify a road map for eventually improving the prediction, diagnosis and treatment of postpartum depression.
“If we routinely show certain brain areas are implicated, what do we do? How can we intervene early?” she said. “What is the normal amount of change? Why might that area be vulnerable? Lots of interesting questions to ask next.”
Study details
Linking birth experience and perinatal depression symptoms to neuroanatomical changes in hippocampus and amygdala
Cristina Ballesteros, H Maria Paternina-Die, Susana Carmona et al.
Published in Science Advances on 5 March 2025
Abstract
Childbirth is a life-changing event in a mother’s life. While the transition to motherhood has recently been recognised as one of the most neuroplastic periods in adulthood, no study has yet explored whether the hippocampus and amygdala change during the peripartum in relation to childbirth experience and perinatal depression symptoms. In this longitudinal neuroimaging study, we assessed 88 first-time gestational mothers in late pregnancy and early postpartum and 30 nulliparous control women. We used optimized high-resolution MRI scans to quantify volumetric changes in the hippocampus and amygdala, along with their substructures. We found that increases in depression symptoms during the peripartum were positively correlated with changes in the right amygdala. A more challenging birth experience was associated with bilateral increases in hippocampal volume. These findings show that studying the neuroanatomical changes during the transition to motherhood can inform not only about adaptive processes but also about potential vulnerabilities, highlighting the importance of tracking perinatal experiences to enhance women’s health.
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Perinatal depression: mums, dads, babies all at risk – London meta-analysis