Maternal Infection and Autism, Intellectual Disability Links Examined

Associations attenuated in sibling analysis indicating that the links were not causal

TUESDAY, Sept. 13, 2022 (HealthDay News) — Maternal infection in pregnancy is associated with autism and intellectual disability in offspring, although the association does not appear to be causal, according to a study published online Sept. 7 in The Lancet Psychiatry.

Martin Brynge, M.D., from Karolinska Institutet in Stockholm, and colleagues examined the associations between maternal infection during pregnancy and children’s risk for intellectual disability and autism and examined whether there is a causal role. Children living in Stockholm born in 1987 to 2010 were included, with data analyzed for 549,967 children.

The researchers found that 1.3 and 3.3 percent of 34,013 children exposed to maternal infection during pregnancy were diagnosed with intellectual disability and autism, respectively, as were 1.0 and 2.5 percent of 515,954 unexposed children, respectively. Exposure to maternal infection during pregnancy was associated with autism and intellectual disability. There was also an association seen for maternal infection in the year preceding pregnancy with autism, but not with intellectual disability. In sibling comparisons, there was an attenuation of the association for maternal infection during pregnancy with autism and to a lesser extent with intellectual disability.

“These models indicate that the commonly observed association between maternal infection during pregnancy and exposed children’s likelihood of autism might be confounded by unobserved factors shared within families, such as shared environment or genetic variation,” the authors write.