Treating depression during pregnancy may benefit baby’s brain development – new research

Treating pregnant women’s depression with a short course of talk therapy doesn’t just improve their health – it can also shape how their babies’ brains develop before birth. That’s the finding of a new study we co-authored, published in the journal Nature Communications.

The study is part of an ongoing research project that explores how a form of brief interpersonal psychotherapy called MOMCare, which is specially tailored to treating prenatal depression, affects pregnant women with depression and their babies. MOMCare consists of eight 50-minute sessions focused on building interpersonal skills, reducing conflict and strengthening social support.

We enrolled 234 pregnant women who reported having symptoms of depression during their routine prenatal care appointments. Mothers joined the research project during the first or second trimester and were randomly assigned to one of two groups.

Women in one group received MOMCare. Women in the other group received education about mental health, strategies for managing depression symptoms and referrals to mental health support services, such as therapy, in the community. Both groups continued getting their usual medical care, which could also include referrals to therapy or medication.

In a previous publication, we found that 36% of moms enrolled in our study were diagnosed with depression in pregnancy before getting MOMCare and just 6% after it, showing the intervention was effective. Women who received the MOMCare intervention were also more likely to carry their baby to term, which is linked with shorter hospital stays after birth and improvements in many aspects of child health and development, including better school performance.

In the current study, to investigate how this form of talk therapy affects a baby’s developing brain, we measured the volume of different brain areas using an imaging technique called magnetic resonance imaging, or MRI, within a few weeks of birth. We found that a brain area called the hippocampus, which plays a role in learning, memory and emotional regulation, was 5% smaller by volume in infants whose mothers received MOMCare compared to mothers in the other group.

Six months later, we brought the babies back into the lab to examine their emotional responses to unfamiliar experiences, such as encountering a noisy toy robot that danced and moved unpredictably. According to earlier studies, babies who respond more negatively to these tasks have higher levels of depression and anxiety in adolescence.

In our study, we found that babies with a smaller hippocampal volume at birth tended to respond less negatively than those with larger volume.

It may seem counterintuitive that a smaller brain volume is associated with stronger emotional regulation, particularly since in adults smaller brain volume is often associated with negative effects. However, in infancy the brain is growing, and faster growth may not always be advantageous. For example, one hypothesis proposes that stress can accelerate early brain development.

Why it matters

Depression affects up to 1 in 5 women during pregnancy. It also raises the risk of pregnancy complications such as high blood pressure and preterm birth. And having depression during pregnancy raises the risk of mental illness in the child.

Pregnancy offers a unique opportunity to simultaneously improve the health of both mother and baby. This is because women often have more contact with the healthcare system during pregnancy than at other times in their lives. Treating a woman’s depression during her pregnancy benefits two generations, improving the health of the mother and her developing baby.

Even though both MOMCare and the control condition in our study provided more support than pregnant women experiencing symptoms of depression often receive, we still saw a big difference between the groups. This suggests that a targeted intervention, even a noninvasive and relatively low-cost one such as MOMCare, can make a big difference.

Our study is the first to show that treating a woman’s depression during pregnancy may influence infant brain development. It aligns with a small but growing number of randomized clinical trials showing that reducing maternal depression has benefits for babies, including improved emotional development and changes in stress-related hormones.

These findings, if confirmed, could explain the biological underpinnings behind why treating prenatal depression is so critical. Further, they support public health initiatives to increase accessible mental health support during pregnancy.

What’s still unknown

It’s not clear how lessening mom’s depression in pregnancy leads to changes in the baby’s brain. It’s possible, for example, that stress-related hormones or inflammation associated with depression could influence brain growth.

Another open question is how the brain changes we observed might affect babies’ development long term. We hope to address this by continuing to follow mothers and babies through early childhood. By tracking conditions such as depression and anxiety as the children get older, we hope to determine whether treating mothers’ depression in pregnancy has lasting benefits for their children’s mental health and well-being.

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