Mother's illnesses don't cause autism in child - scientists

Source: Janecka et al. "Most associations between maternal health and autism are attributable to familial confounding" Nature Medicine (2025). DOI: 10.1038/s41591-024-03479-5

Previously, many experts believed that various maternal health disorders could increase the risk of autism spectrum disorders (ASD) in the next generation. However, fresh evidence indicates that in fact almost all such "links" can be explained by genetic predisposition, external factors (e.g., pollution), and even the health care system.

To reach these conclusions, the researchers analysed the medical records of more than 1.1 million pregnancies from Denmark's nationwide registry. Unlike in the US, where medical data is often scattered across different clinics, in Denmark all health information for each resident is stored under a single number. Because of this, scientists were able to check over 1,700 different diagnoses encountered by mums-to-be, and then focused on the 236 that were caught most often.

The results showed that almost all of the conditions found in pregnant women lost their statistical association with autism after taking into account important factors: the mother's age, social status, presence of other diagnoses, and family characteristics, including the role of the father. It turned out that if a man had the same disorder and yet the child developed autism, it was most likely the genes passed down from both parents, rather than the mother's condition during pregnancy, that was the cause.

The only group of disorders that retained a significant association with autism risk were complications related not to the pregnant woman's body, but to the fetus itself. According to the authors, this indicates that such "symptoms" may be early manifestations of ASD rather than the true causes of it. The scientists suggest that the features of autistic development are laid down even before birth and gradually progress in the child's body.

Thus, the new study refutes the popular belief that various maternal illnesses - from depression to hypertension - directly cause autism. Many mums feel guilty thinking that their health during pregnancy may have influenced a future diagnosis. However, the findings of a team from NYU Langone Health suggest that much of such fears are unfounded. The authors emphasise that ridding families of guilt and incorrect stereotypes can help direct efforts to better help children with ASD and their relatives.