Racial and Ethnic Differences in Maternal Health and Autism.

Importance: Autism affects 1 in every 31 children in the US, with significant racial and ethnic disparities in prevalence, age at diagnosis, and access to services. Maternal health conditions during pregnancy have been linked with autism in offspring. However, the extent to which these associations vary by maternal race and ethnicity remains understudied. Objective: To evaluate whether associations between maternal conditions during pregnancy and the risk of autism in offspring differ by maternal race and ethnicity. Design, Setting, and Participants: This retrospective cohort study included children born at Kaiser Permanente Northern California from 2010 to 2017, followed up until February 29, 2020, autism diagnosis, disenrollment, or death. Data were analyzed from September 2024 to July 2026. Exposures: Maternal International Classification of Diseases, Ninth Revision and Tenth Revision diagnoses of any of 25 conditions previously identified as associated with autism during the perinatal period. Main Outcomes and Measures: Cox proportional hazards models examined associations between maternal diagnoses and autism with racial and ethnic differences evaluated via stratified and interaction models. Covariates included maternal age at delivery, insurance type, child sex, birth year, and maternal health care utilization. Results: Of 224 353 children, 5448 (2.4%) were diagnosed with autism, with prevalence varying by maternal race and ethnicity (493 Black [3.2%], 1693 Asian and Pacific Islander [2.9%], 1309 Hispanic [2.5%], 1838 White [2.0%], and 115 other or unknown race and ethnicity [2.4%] children; percentages indicate prevalence within each race and ethnicity group). Associations between maternal health conditions during pregnancy and offspring autism were largely consistent across racial and ethnic groups. Differences in risk estimates by maternal race and ethnicity were observed for 4 of the 25 conditions, including overweight and obesity, depressive episode, asthma, and other maternal disease complicating pregnancy. All those conditions exhibited stronger associations with autism in White mothers, compared with Black, Hispanic, and Asian and Pacific Islander mothers. Conclusions and Relevance: In this cohort study of 224 353 children-mother pairs, maternal health conditions during pregnancy showed consistent observational associations with autism across racial and ethnic groups, but some exhibited heterogeneous association estimates. These differences may reflect disparities in health care access, diagnostic practices, or unmeasured environmental and genetic factors. Further research is needed to clarify underlying mechanisms and implications for maternal and child health.