Key finding: A Lancet review of 43 studies found no convincing evidence that prenatal acetaminophen (Tylenol) causes autism, ADHD or intellectual disability when rigorous study designs are used. Lead author Dr. Asma Khalil said acetaminophen remains the recommended first-line treatment for pain or fever in pregnancy. Some studies and reviews report small associations, but these are likely affected by confounding factors and biases. Experts warn that discouraging acetaminophen could leave fevers untreated, posing clear risks to fetal health.
Major Review Finds No Causal Link Between Prenatal Tylenol Use and Autism — Rigorous Studies Show Safety in Pregnancy
FILE - Tylenol pain-relief pills are shown in La Habra, Calif., Sept. 23, 2025. (AP Photo/Jae C. Hong, File)(ASSOCIATED PRESS)
A comprehensive review published in The Lancet Obstetrics, Gynecology & Women’s Health analyzed 43 studies and found no convincing evidence that taking acetaminophen (Tylenol) during pregnancy causes autism, ADHD or intellectual disability in children when the most rigorous study designs are used.
What the Review Found
The review’s authors emphasized that studies using stronger methods — particularly sibling-comparison designs that help control for shared genetics and family environment — generally do not show a causal association between prenatal acetaminophen exposure and later neurodevelopmental disorders. Lead author Dr. Asma Khalil summarized the findings:
"It's safe to use in pregnancy. It remains … the first line of treatment that we would recommend if the pregnant woman has pain or fever."
Why Some Studies Suggest a Link
Other papers and reviews have reported small associations between prenatal acetaminophen and neurodevelopmental outcomes. For example, a review in BMC Environmental Health pooled many studies and reported an association. Critics point out that many of those studies were small, used weaker methods, or were vulnerable to biases such as confounding and recall bias.
Confounding can occur when the reason a woman takes acetaminophen — for example, fever or infection — is itself associated with higher risk to the fetus. Recall bias can affect studies that rely on mothers’ memories of medication use years later. The BMC review’s senior author, Dr. Andrea Baccarelli, disclosed he served as an expert witness in litigation related to this issue.
Clinical Context and Implications
Experts stress balance: acetaminophen remains an important and commonly recommended option for managing pain and fever in pregnancy. Several commentators who were not part of the Lancet review warned that discouraging acetaminophen use could lead to undertreated fever or infection, which carry known risks to fetal survival and neurodevelopment.
Genetics remain the largest known risk factor for autism. Other established risks include advanced paternal age, preterm birth and maternal medical complications during pregnancy.
Bottom Line
When higher-quality study designs are prioritized, the apparent association between prenatal acetaminophen use and neurodevelopmental disorders is not seen. Pregnant people should consult their clinicians about treating pain or fever and should not stop recommended treatments based on preliminary or methodologically limited studies.
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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.
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