Maternal infections during pregnancy increase the risk of suicidal behaviors in their offspring, study finds

Past medical research consistently showed that specific events unfolding during pregnancy can influence the health of their offspring after birth. While this has been widely observed in the context of physical health, for instance, when it comes to the effects of drinking alcohol, high caffeine intake or smoking during pregnancy, the link between a mother’s health during pregnancy and their children’s mental health remains widely unexplored.

Researchers at McGill University, the Danish Research Institute for Suicide Prevention, University of Copenhagen and Johns Hopkins Bloomberg School of Public Health recently carried out a large-scale study investigating the possible connection between maternal infections during pregnancy and the risk that offspring will exhibit suicidal behavior later in life. Their findings, published in Molecular Psychiatry, suggest that children who were exposed to an infection while they were still in their mother’s womb are at a higher risk of attempting suicide.

“Most studies on suicide risk have focused on what happens shortly before a crisis, helping clinicians identify who may be at immediate risk,” Dr. Massimiliano Orri, first author of the paper, told Medical Xpress. “However, research increasingly shows that vulnerability to suicide can begin much earlier in life. We wanted to look further upstream and understand how early-life factors might shape suicide risk over the long term.”

A large-scale study of maternal infections and suicide risk

Infections caused by an exposure to specific viruses or bacteria activate an immune response known as inflammation. Dr. Orri and his colleagues decided to focus on maternal infections during pregnancy because inflammation at crucial stages of brain development has previously been linked to a higher risk of developing some mental health disorders.

As part of their recent study, the researchers analyzed a large amount of data extracted from Denmark’s national health registers. The Danish national health registers store detailed health-related information and records for all individuals living in Denmark, including their hospital visits, emergency care they received and any medical or psychiatric diagnoses.

“These records also include data on education, employment, and living conditions,” explained Dr. Orri. “Crucially, they allow researchers to link parents and children, making it possible to identify mothers who experienced infections during pregnancy and then follow their children over time. This enabled us to examine whether suicide attempts were more common among people whose mothers had an infection while pregnant, compared with those who did not, while taking social and economic factors into account.”

The dataset analyzed by Dr. Orri and his colleagues is remarkably large, as it contains information relating to over 2 million individuals. This ultimately allowed the researchers to reliably search for associations between maternal infections and suicidal behaviors, which would be difficult to uncover within smaller datasets.

The researchers analyzed the health records of all individuals above the age of 10 in the period spanning from 1987 to 2021. They specifically looked for maternal and paternal infections, before, during and after they were expecting a child, as well as their children’s hospital visits after the age of 10.

“Ours was one of the largest studies to date examining the link between maternal infections during pregnancy and suicidal behavior, and one of the few to look closely at different types of infections and differences between males and females,” said Dr. Orri.

“We also used a particularly robust approach by comparing maternal infections with paternal infections that occurred during the same period. Because fathers are not biologically involved in pregnancy, their infections cannot directly affect fetal development.”

Implications and future research directions

Based on their analyses, Dr. Orri and his colleagues estimated that if a mother was exposed to a bacterial or viral infection while she was pregnant, her child had a 46% higher risk of attempting suicide. This percentage appeared to be higher if infections occurred during the second or third trimester. Surprisingly, the risk of offspring attempting suicide was also higher when mothers contracted an infection before or after their pregnancy than if they contracted no infection at all, which could suggest either long-lasting effects of infections or the presence of residual confounding factors.

“It is important to know that this study shows statistical association,” added Dr. Orri, “This means that an infection in pregnancy does not usually or necessarily lead to later suicidal behavior. Indeed, most children whose mothers have had infection during pregnancy grow up without developing serious mental health problems or suicide risk.”

Interestingly, the researchers found that while maternal infections were linked to a higher risk of suicide attempts in offspring, paternal infections were not. This suggests that the link they observed is unlikely to be a result of social or family-related factors, as it would also hold true for paternal infections, but that it is instead rooted in fetal brain development.

The results of this recent study suggest that women’s health before, during and right after pregnancy could be very important for the prevention of mental health-related issues and the reduction of suicide rates. If they are validated by further studies, these findings could inform the development of new preventative care strategies or targeted interventions for teenagers or young adults who are at a higher risk of suicide.

“Future research will continue to explore other early-life factors that may shape long-term vulnerability to suicide, including complications during pregnancy and childbirth,” added Dr. Orri. “By broadening this perspective, we hope to better understand how risks accumulate over the life course.”

© 2026 Science X Network