Prenatal talk therapy linked to calmer infant responses and altered hippocampus

A brief course of interpersonal therapy for depression during pregnancy was associated with a smaller right hippocampus and less negative emotional reactivity in babies at six months.

Treating depression during pregnancy with a short, targeted course of talk therapy may do more than ease symptoms for the mother.It may also shape early brain development in the baby, according to a study published in Nature Communications and described by researchers involved in the work.

The trial followed 234 pregnant women who reported depressive symptoms during routine prenatal visits and were enrolled in the first or second trimester. Participants were randomly assigned either to MOMCare, a brief form of interpersonal psychotherapy designed specifically for prenatal depression, or to an education-and-referral group that received mental health information, coping strategies and help accessing community services. Both groups continued with standard obstetric care. In earlier reporting on the same study, the researchers said depression diagnoses in the MOMCare group fell from 36% before treatment to 6% afterwards, and that those women were also more likely to carry to term.

Using MRI scans taken within weeks of birth, the researchers found that infants whose mothers received MOMCare had a right hippocampus that was about 5% smaller than that of babies in the comparison group. The hippocampus is involved in memory, learning and emotional regulation. When the babies were assessed again at six months of age, those with smaller hippocampal volumes tended to show less negative emotional responses in a lab test that included an unexpected, noisy toy robot.

The result may sound counter-intuitive, since a smaller brain volume in adulthood is often associated with poorer outcomes. But in infancy, the brain is still rapidly developing, and the authors say faster growth is not always better. They suggest that reducing maternal stress may alter hormones or inflammation that influence fetal brain development. The study does not yet prove how those biological changes work, nor whether the brain differences will persist as children grow, but the researchers plan to continue following families into early childhood to see whether the benefits extend to later mental health and development.

The findings add to a small but growing body of evidence that treating depression during pregnancy can benefit both mother and child. The researchers argue that pregnancy may be a particularly important window for intervention because women often have repeated contact with healthcare providers at that time, making it easier to identify and treat depression before it affects the rest of the family.