Hidden Costs of Stress During Pregnancy

A groundbreaking study spearheaded by Prof. Hermona Soreq and Shani Vaknine Treidel from the Edmond and Lily Safra Center of Brain Science reveals the profound impact of prenatal stress on newborns—especially female babies. Published in the journal Molecular Psychiatry, this research highlights how a mother’s psychological state during pregnancy can trigger molecular changes in her child.

The Science Behind Prenatal Stress

Focusing on perceived prenatal stress (PPS), the researchers examined how a mother’s mental strain during pregnancy rewires molecular pathways in her baby’s body. The cholinergic system, which plays a pivotal role in managing stress and inflammation, appears to be notably affected. As Prof. Soreq put it, "The stress experienced by mothers shapes how their children will manage stress long before they even take their first breath."

Remarkable Findings from Umbilical Cord Analysis

The study analyzed umbilical cord blood from infants born to mothers who reported elevated stress levels during their third trimester. Researchers honed in on tiny RNA molecules known as tRNA fragments (tRFs), crucial in regulating gene expression. Astonishingly, the impact of maternal stress extended beyond individual tRFs and affected entire families of these molecules, particularly those derived from mitochondrial DNA.

Sex-Specific Responses: Girls in the Spotlight

Remarkably, the effects of prenatal stress were sex-specific. Female newborns experienced the most significant alterations, including a dramatic reduction in certain mitochondrial tRFs, dubbed "CholinotRFs." These specific tRFs are closely linked to genes that control acetylcholine—a neurotransmitter vital for brain function and immune health.

Unraveling the Impact on Stress Responses

The study further analyzed the enzyme acetylcholinesterase (AChE), which breaks down acetylcholine. Newborns of stressed mothers, particularly the boys, exhibited notably higher levels of AChE, hinting at a disrupted stress-response system from birth.

Implications for Future Health

These molecular modifications may shed light on why children exposed to elevated maternal stress during pregnancy are at a higher risk for neurodevelopmental and psychiatric conditions in later life. The researchers utilized machine learning methods to categorize female newborns based on their CholinotRF profiles, achieving a remarkable 95% accuracy in identifying whether they were exposed to prenatal stress.

A Call to Prioritize Maternal Mental Health

Vaknine Treidel emphasized, "This study offers a profound insight into how the maternal environment can impart lasting biological effects on future generations. It highlights the critical need to support mental health during pregnancy—not just for the mother, but also to safeguard the health of the child well into adulthood."

A Collaborative Exploration

This research was part of the international FELICITy project, in cooperation with institutions such as the Technical University of Munich and the University of Washington. Over 120 mother-infant pairs provided blood samples for this revelatory study, analyzed at the Hebrew University's Center for Genomic Technologies.