How Infections in Pregnancy May Shape Mental Health

Maternal infections during pregnancy could have long-lasting effects on a child’s mental health, according to new international research. A massive population study now shows that children exposed to infections in the womb face a higher risk of suicide attempts later in life.
The findings add to growing evidence that what happens during pregnancy matters not only for physical development, but also for future emotional well-being.
Researchers from McGill University, Danish Research Institute for Suicide Prevention, University of Copenhagen, and Johns Hopkins Bloomberg School of Public Health published their work in Molecular Psychiatry.

Looking beyond short-term suicide risk

Most suicide research focuses on warning signs that appear shortly before a crisis. However, lead author Massimiliano Orri said his team wanted to look much earlier in life.
Their goal was simple but important: understand whether infections during pregnancy could shape a child’s risk of suicidal behaviour years or even decades later.
Previous studies already linked inflammation during fetal brain development to certain mental health conditions. Since infections trigger inflammation, the researchers suspected they might also influence long-term suicide risk.

How the researchers studied more than 2 million people

The team analysed national health records from Denmark, covering over 2 million individuals. These detailed registries track hospital visits, diagnoses, education, employment, and family links.

This allowed scientists to:

Identify mothers who had bacterial or viral infections during pregnancy
Follow their children from age 10 onward
Record suicide attempts through hospital data
Adjust for social and economic factors

They also examined infections in fathers during the same periods. Because fathers do not carry the pregnancy, this comparison helped rule out shared family or environmental influences.

The study followed people from 1987 through 2021, making it one of the largest investigations ever conducted on maternal infections during pregnancy and suicide risk.

Key findings

Children whose mothers had an infection while pregnant showed a 46 per cent higher risk of attempting suicide later in life.

The risk appeared strongest when infections happened during the second or third trimester, a critical time for brain development.

Even more surprising, researchers saw a higher risk when mothers experienced infections shortly before or after pregnancy, compared with mothers who had no infections at all. This may point to longer-lasting biological effects or other hidden factors.

Importantly:

Maternal infections increase the risk
Paternal infections did not

This difference strongly suggests that changes in fetal development, not family stress or social background, likely drive the association.

Still, Dr Orri emphasised that the study shows association, not certainty.

Most children exposed to maternal infections during pregnancy do not go on to develop serious mental health problems or suicidal behaviour.

Why inflammation during pregnancy may matter

When a pregnant woman gets sick, her immune system releases inflammatory signals. These signals can cross the placenta and impact the developing brain.
Scientists believe this early disruption may subtly change how stress, mood, or emotional regulation systems form, increasing vulnerability years later.
This does not mean infections directly cause suicide. Rather, they may contribute to a chain of risks that builds over time.

What this means for mothers and public health

These findings highlight how important women’s health is before, during, and just after pregnancy.

Better infection prevention, early treatment, and close follow-up may help reduce future mental health risks in children. In the long run, this research could guide:

Improved prenatal care strategies
Early screening for at-risk adolescents
Targeted mental health support for young people

Maternal infections during pregnancy may become an important factor that doctors consider when assessing long-term well-being.

Conclusion

The research team plans to study other early life influences, including pregnancy complications and birth-related issues, to better understand how suicide risk develops across the lifespan.
By identifying these early markers, scientists hope to move prevention upstream and support vulnerable children long before a crisis begins.

Source: Inputs from various media Sources

Priya Bairagi

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I’m a pharmacist with a strong background in health sciences. I hold a BSc from Delhi University and a pharmacy degree from PDM University. I write articles and daily health news while interviewing doctors to bring you the latest insights. In my free time, you’ll find me at the gym or lost in a sci-fi novel.