Stress in pregnancy affects baby’s brain before birth, discovers Israeli researchers

The discovery led by researchers from the Hebrew University of Jerusalem (HU) could pave the way for new treatments or interventions to support a baby's healthy development after birth

Jerusalem: Israeli researchers have discovered that stress experienced by mothers during pregnancy affects the foetus’s brain.

The discovery led by researchers from the Hebrew University of Jerusalem (HU) could pave the way for new treatments or interventions to support a baby’s healthy development after birth, Xinhua news agency reported.

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Published in the journal Molecular Psychiatry, the study revealed that maternal stress during pregnancy could “reprogramme” key molecular pathways in the foetus, particularly the cholinergic system — a network of nerve cells responsible for regulating stress responses and inflammation.

The researchers analysed blood samples from 120 newborns and their mothers collected at birth, focusing on small RNA molecules known as tRNA fragments (tRFs), many of which originate from mitochondrial DNA.

These molecules play a critical role in regulating cellular functions and responses to stress.

“We found that even before babies take their first breath, the stress their mothers experience can shape how their bodies manage stress themselves,” said Prof. Hermona Soreq, from the Hebrew University of Jerusalem.

The study also uncovered major differences between male and female infants. Baby girls showed a sharp decrease in specific tRFs, called CholinotRFs, which are involved in the production of acetylcholine — a brain chemical crucial for memory and immune function.

While baby boys showed elevated levels of an enzyme (AChE) that breaks down acetylcholine, suggesting a diminished capacity to manage stress.

Using machine learning, the researchers determined with 95 per cent accuracy whether baby girls had been exposed to maternal stress during pregnancy based on their RNA profiles.

This discovery may help explain why children exposed to stress in the womb are more likely to face mental health or developmental challenges later in life.

The researchers said the findings could raise awareness and lead to better support for pregnant women under stress, even if they don’t have a formal diagnosis of anxiety or depression.