Lead
On Sept. 6, 2025, the U.S. Department of Health and Human Services confirmed it is preparing a report, expected this month under Secretary Robert F. Kennedy Jr., that will examine possible links between prenatal acetaminophen use, certain vitamin issues and autism spectrum disorder; HHS declined to preview conclusions while many medical experts say current evidence does not support causal claims.
Key Takeaways
- HHS says a report on autism causes is being finalized and may address prenatal acetaminophen and vitamin-related factors.
- Media reports say the draft suggests a connection between acetaminophen use in pregnancy and autism, and proposes folate-related interventions such as leucovorin.
- HHS declined to confirm findings, calling any discussion before release speculative.
- Major medical groups, including the Society for Maternal-Fetal Medicine, continue to recommend acetaminophen for fever and pain in pregnancy.
- A large NIH-funded 2024 study found no increased autism risk from prenatal acetaminophen exposure.
- Leucovorin (folinic acid) is used medically for certain folate deficiencies and is sometimes prescribed off-label for autism; robust evidence of benefit is limited.
Verified Facts
The Department of Health and Human Services confirmed it is working on a report addressing causes of autism and would not discuss conclusions before publication. A spokesperson told reporters that “until we release the final report, any claims about its contents are nothing more than speculation.”
Press accounts have said the report will examine whether acetaminophen (sold as Tylenol) taken during pregnancy and particular vitamin or folate-related conditions are associated with autism spectrum disorder (ASD). The report is reported to mention leucovorin (folinic acid) as a potential preventive or treatment angle, though that use is off-label for ASD.
Medical organizations cited by news outlets emphasize that acetaminophen is generally recommended during pregnancy to treat fever and pain. The Society for Maternal-Fetal Medicine noted that untreated fever in early pregnancy is linked to miscarriage and birth defects and that treating maternal pain has its own health benefits.
Regarding the science, several small studies have reported associations between fetal acetaminophen exposure and later diagnoses of ASD or ADHD, but the largest available study — an NIH-funded collaboration published in 2024 — found no increased risk. A U.S. District Court reached a similar conclusion in a product-liability case examining the same question.
Context & Impact
Autism is a neurodevelopmental condition with a complex etiology. Hundreds of genes have been implicated, and researchers continue to study how genetic predispositions might interact with environmental factors. Experts warn against simplifying autism’s causes to a single medication or nutrient.
If the HHS report receives public attention for linking acetaminophen to autism without strong supporting evidence, it could prompt confusion among pregnant people and clinicians. That, in turn, could lead to reduced use of an accessible medication used to manage fever — a condition that itself carries risks in pregnancy — or to increased demand for unproven treatments.
Leucovorin (folinic acid) differs from synthetic folic acid and is used to treat specific medical deficiencies, for example those induced by certain chemotherapies. A small body of research explores whether folate transport differences in some people with autism could be addressed with folinic acid, but randomized, large-scale trials demonstrating clear clinical benefit are lacking.
Official Statements
“Until we release the final report, any claims about its contents are nothing more than speculation.”
HHS spokesperson (statement to reporters)
“It is disingenuous and misleading to boil autism’s causes down to one simple thing,” said an expert emphasizing the multifactorial nature of autism and the limitations of current studies.
Autism Science Foundation (public statement)
Unconfirmed
- Whether the final HHS report will assert a causal link between prenatal acetaminophen use and autism is unconfirmed until publication.
- Claims that leucovorin can prevent autism remain unproven and lack consensus from large-scale clinical trials.
Bottom Line
HHS has acknowledged a forthcoming report on autism causes that may raise questions about prenatal acetaminophen and folate-related interventions, but leading researchers and clinical societies urge caution: the best-available large study to date found no increased risk from prenatal acetaminophen, and evidence for leucovorin as an autism treatment is limited. Clinicians and patients should continue to follow established medical guidance on treating fever and pain in pregnancy while awaiting the report’s full, peer-reviewed findings.