Treating depression in pregnancy may shape baby's brain, CU Anschutz study finds

Treating depression during pregnancy with a short course of talk therapy may also shape the baby's developing brain, according to a study published in the journal Nature Communications around October 16, 2026. Researchers at the University of Colorado Anschutz Medical Campus, led by assistant professor of psychiatry Catherine Demers, followed 109 infants whose mothers had taken part in a randomised clinical trial for depression during pregnancy. Babies whose mothers received brief interpersonal psychotherapy had a smaller right hippocampus, a brain region involved in memory and emotion, than babies whose mothers received enhanced usual care. In the study, a smaller right hippocampus went with lower negative emotionality, meaning fewer signs of distress, when the babies were six months old. The university describes it as the first randomised controlled trial to show that a treatment for prenatal depression can affect infant brain structure.

Depression during pregnancy is common, yet it is often missed or dismissed as ordinary worry or tiredness. Many women hesitate to seek help because of stigma, or because they fear that medicines could harm the baby. This study looks at a treatment that involves no medicine at all: a structured, time-limited form of talk therapy that helps a woman deal with conflicts, role changes and loneliness, and build support around her.

Earlier research has repeatedly linked a mother's depression or stress in pregnancy with differences in her baby's brain, though the findings vary between studies. What has been missing is evidence that treating the mother changes anything for the child. Because this study grew out of a randomised trial, in which women were assigned to therapy or usual care by chance, it gives a stronger hint that the therapy itself, rather than other differences between families, lies behind the brain difference.

The findings need careful reading. The brain measures were exploratory, the group of infants was relatively small, and the paper and the university's press material describe the result in slightly different terms. A smaller hippocampus is not simply better or worse; what matters is how the structure develops over time and how it relates to the child's behaviour, which only longer follow-up can show. The researchers' work is a reason to take prenatal mental health seriously, not a promise about any individual baby.

For women balancing work, family and a pregnancy, the practical message is simple. Low mood, loss of interest, constant anxiety or trouble sleeping that lasts for weeks during pregnancy is worth raising with a doctor or midwife, and effective help exists that does not depend on medication.

Study at a glance Item | Detail Journal | Nature Communications Published | Around October 16, 2026 Participants | 109 infants of mothers in a prenatal depression trial Treatment | Eight weekly 50-minute sessions of interpersonal psychotherapy Main brain finding | Smaller right hippocampus in the therapy group

Short-term: The study adds weight to calls for routine screening for depression during pregnancy and for making short talk-therapy programmes available in antenatal care, including in clinics that serve women with fewer resources.

Long-term: If later follow-up confirms that treating prenatal depression changes how children's brains and emotions develop, maternal mental health care could come to be seen as an early investment in children's health, not only a service for mothers.

Who is affected: Pregnant women living with depression or anxiety, their partners and families, obstetricians, midwives and community health workers, and mental health services that plan care around pregnancy.

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