A recently published found associations between certain maternal health conditions during pregnancy and autism diagnoses across racial and ethnic groups, underscoring how much remains unknown as the Trump administration searches for a cause of autism. Researchers from the New York University Grossman School of Medicine and the Kaiser Permanente School of Medicine published a study earlier this month that included 224 ,353 children born at Kaiser Permanente Northern California hospitals between 2010 and 2017.

Out of the more than 200,000 children, 2.4 percent were diagnosed with autism — not too far off from the 3.2 percentage rate reported by the Centers for Disease Control and Prevention (CDC). Across different racial and ethnic groups, autism rates generally hovered around 2 and 3 percent. But other findings stood out: Four out of 25 maternal health conditions — obesity, depressive episode, asthma and other maternal diseases complicating pregnancy — had a higher association with autism diagnoses when it came to white mothers than mothers who were Black, Hispanic or Asian and Pacific Islander.

Magdalena Janecka, associate professor at the Grossman School of Medicine's department of child and adolescent psychiatry and co-author of the study, said the research highlighted the need to further examine environmental factors. "I think this study highlights that the link between certain environmental factors and autism (and other conditions) is likely to be heterogeneous across different population groups: not because the fundamental biology differs, but because what these environmental factors entail may differ among different individuals," Janecka said in written responses to The Hill.

She emphasized that these findings are "definitely not" indicative that "these maternal conditions cause autism." "Instead, it may indicate that some factors related to this maternal condition (e.g., genetic factors) are also implicated in autism.

We still need to do more research to understand what exactly drives these effects," she added. That conclusion is unlikely to satisfy the Trump administration, as some have set out on a mission to find the cause of autism. Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. in April 2025 said the administration would determine the cause of rising autism rates by September of that year. When the deadline came around, he and President Trump speculated from the Oval Office that the common over-the-counter pain reliever acetaminophen taken during pregnancy could be linked to autism, without presenting new evidence.

This claim was denounced by maternal medicine groups and autism advocates alike. A month later, Kennedy walked back this claim somewhat, saying there "is not sufficient to say it definitely caused autism, but it is very suggestive." Kennedy has also long refused to discount the theory that vaccinations could be linked to autism, despite no evidence being found linking immunizations to later diagnoses. A CDC page published earlier this year claims "studies supporting a link have been ignored by health authorities."

The overarching position of groups like the nonprofit Autism Speaks is that autism spectrum disorder develops as a result of both genetic and environmental influences. This is a position that Janecka shares. "Our study neither supports nor challenges this," said Janecka. "We don’t know what exactly drove the observations we reported, and so it is difficult to attribute them to either genetic or non-genetic factors." In discussing their findings, researchers acknowledged that differences in access to care, insurance continuity, clinical follow-up and treatment patterns could have affected what they observed.

An opinion piece published last year, co-authored by Janecka, argued differences in potential causes of childhood neuropsychiatric outcomes are "often overlooked," with social determinants often filtered out of analyses.

"As race/ethnicity is primarily a social construct—associated with experiences of structural inequities, racism, and environmental injustice—that aligns poorly with genetic ancestry, we emphasize that the differences in the exposure–outcome associations across race/ethnic strata would arise largely because of societal, rather than biological, causes," the authors wrote.

The study published this month took into account the history of underdiagnosis among certain groups, like the children of Black mothers being less likely to receive a diagnosis even when scoring high for autism-related traits in testing. According to experts, autism does not occur at different rates across different races and ethnicities.

"We don't have any evidence that shows that there's any difference across race ethnicity in terms of autism diagnosis," said Andy Shih, chief science officer of Autism Speaks. "We do see ... racial, ethnic differences in terms of diagnosis between white kids and Asian kids and African American kids, Hispanic kids for example," Shih added. "But you know those gaps have been closing. So, I think the latest report that we have — it actually shows that at least at national level that we have closed the gap in terms of some ethnicity-based assessment."

Shih hopes that the findings from the study bring more attention to the need for "the best healthcare access for expectant mothers." Janecka added, "What I would hope our study highlights is the need for more studies like ours stratifying the observed effects by maternal race/ethnicity, as well as considering other ways to stratify the total population: based on e.g., insurance status. I think rather than regress some differences out of our models, we should strive to better understand them." The Hill has reached out to HHS for comment.