Stress during pregnancy could affect the baby's development

Maternal stress could leave epigenetic imprints on genes in the placenta associated with cortisol — a necessary hormone for fetal development — and this would affect the baby’s development from very early stages. That’s according to a study published in the journal European Neuropsychopharmacology, which suggests that a mother’s emotional wellbeing during pregnancy is not only important for her, but also the future health of her baby.

The placenta is an essential organ during pregnancy — not only does it provide oxygen and nutrients to the fetus, it also responds to factors such as maternal stress and helps the fetus adapt to its environment. However, the mechanisms by which the placenta adjusts to these stressors and how it influences fetal development remain largely unexplored.

A team of Spanish and German researchers, led by Professor Lourdes Fañanás from the University of Barcelona and the Network Centre for Biomedical Research in Mental Health (CIBERSAM), observed that maternal stress may leave epigenetic marks on certain placental genes. Specifically, these marks do not modify the genetic structure, but they do alter its function. The study identified epigenetic changes in genes related to the regulation of cortisol, an essential hormone in the body’s response to stress.

The pilot study involved 45 healthy, first-time pregnant women. During pregnancy, their cortisol levels and depressive symptoms were measured and, after delivery, placentas were analysed. At seven weeks, the neurodevelopment of the babies was assessed using a specialised test (Brazelton’s NBAS).

The research team used an advanced sequencing technique that allows them to look at epigenetic changes in large areas of DNA and thus gain a very detailed view of the placental response to maternal stress. This method identified changes in key genes involved in cortisol regulation, such as HSD11B2, NR3C1 and FKBP5. The results suggest that maternal stress — especially in early pregnancy — can cause alterations in these genes, which could affect fetal development and the future health of the baby.

“This study reinforces the importance of taking care of the mental health of mothers from the beginning of pregnancy, since stress could leave a biological imprint on the baby’s development through epigenetic mechanisms that we are just beginning to understand,” said first author Águeda Castro, a CIBERSAM researcher at the University of Barcelona.

Although this is a pilot study, the results open the door to future research and possible interventions to support pregnant women in vulnerable situations from the earliest stages. While the findings need to be replicated in larger studies, they underscore the importance of psychological care and emotional support during pregnancy — not only for the mother’s wellbeing, but also for the long-term health of the baby.

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