Talk therapy for depression in pregnancy linked to changes in babies’ brains

A short course of interpersonal psychotherapy was associated with smaller hippocampi and less negative emotional responses in infants, although the long-term significance remains unclear.

Treating depression during pregnancy with a short course of talk therapy may do more than ease symptoms for the mother. New research published in Nature Communications suggests it can also influence how the baby’s brain develops before birth, adding to growing evidence that maternal mental health care can have benefits across generations.

The study followed 234 pregnant women who reported depressive symptoms during routine antenatal visits and were enrolled in the first or second trimester. Participants were randomly assigned either to MOMCare, a brief form of interpersonal psychotherapy designed for prenatal depression, or to an education and referral programme that offered information, coping strategies and links to community mental health support alongside usual medical care. MOMCare typically involves eight 50-minute sessions centred on relationships, conflict resolution and strengthening social support, according to the University of Washington programme description.

In earlier analysis from the same project, the researchers found that depression diagnoses fell sharply among women who received MOMCare, and that they were also more likely to carry their pregnancies to term. That matters because preterm birth is linked with longer hospital stays and poorer outcomes for children, while untreated depression during pregnancy is associated with complications including high blood pressure and a higher risk of later mental illness in offspring, according to clinical reviews and previous trials of brief interpersonal psychotherapy.

The new study looked at babies within weeks of birth using MRI scans and found that infants whose mothers had received MOMCare had a hippocampus that was about 5% smaller in volume than those in the comparison group. The hippocampus is involved in learning, memory and emotional regulation. When the babies were brought back at six months and exposed to a mildly unsettling toy designed to provoke an emotional reaction, those with smaller hippocampal volume tended to respond less negatively. The researchers said the result may seem surprising, but in early life a smaller brain volume does not necessarily imply poorer development, since the infant brain is still rapidly growing and stress may alter the pace of that growth.

The findings do not yet explain how treating maternal depression changes the baby’s brain, and the researchers say hormones linked to stress or inflammation may be part of the answer. They also caution that it remains unknown whether the differences seen in infancy translate into long-term effects. Even so, the study adds to a small but expanding body of research suggesting that reducing depression during pregnancy can improve outcomes for both mother and child, supporting wider efforts to make accessible mental health care a routine part of antenatal care.