Infections in womb linked to autism and intellectual disability risk

By the Editorial Team · Tuesday, September 22, 2026

Researchers at the Karolinska Institute found that congenital infections contracted before birth are linked to a threefold increase in autism risk and a sevenfold increase in intellectual disability among children. The study highlights the importance of vaccination and preventive measures during pregnancy to reduce fetal infection, although it cannot prove a direct causal relationship.

A recent study conducted by researchers at the Karolinska Institute in Sweden has found a potential association between congenital infections contracted in the womb and an increased risk of autism and intellectual disability. The study analyzed the health records of 3.7 million individuals born in Sweden between 1987 and 2021.

Among these cases, 975 were diagnosed with congenital infections classified under the "TORCH" group, which includes toxoplasmosis, syphilis, rubella, cytomegalovirus, and herpes simplex. The researchers found that children exposed to these infections before birth were approximately three times more likely to receive a diagnosis of autism and seven times more likely to be identified with an intellectual disability compared to those without such infections.

Unlike previous research that focused on whether the mother experienced an infection during pregnancy, this study concentrated on infections that had crossed the placental barrier to infect the fetus directly. The researchers emphasized that congenital transmissions of these infections are relatively rare. Reneé Gardner, a co-author of the study, noted, "It is important to emphasize that it is unusual for these infections to be transmitted from mother to child."

The research, published in JAMA Pediatrics, suggests that the findings bolster the importance of vaccination and other preventive measures to reduce the risk of infections passing from pregnant mothers to their unborn children.

However, the study was observational and cannot establish a direct cause-and-effect relationship between congenital infections and the development of autism or intellectual disability. Additionally, it relied solely on cases where congenital infections were clinically diagnosed, potentially overlooking milder or asymptomatic infections that may have gone undetected.

Overall, while the study points to a significant correlation between congenital infections and neurodevelopmental conditions, further research is needed to better understand the mechanisms involved and to guide public health interventions.

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