Large Study Finds No Link Between Tylenol Use During Pregnancy and ADHD or Autism

Researchers compared siblings to account for shared factors like genetics and environment.

Published on Mar. 10, 2026

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A study of 2.1 million births in Taiwan found that children whose mothers were prescribed acetaminophen, commonly known as Tylenol, during pregnancy were slightly more likely to be diagnosed with ADHD or autism. However, when the researchers compared siblings, the link disappeared, suggesting other underlying factors may explain the initial pattern.

Why it matters

The possible connection between prenatal acetaminophen exposure and neurodevelopmental conditions has been debated for years, with studies producing mixed results. This large study provides more evidence that there may not be a direct causal link, and that other maternal health factors or environmental influences could be responsible for any small increased risks.

The details

The study analyzed national health records from nearly 2.1 million births in Taiwan between 2004 and 2015. Close to half the children (48%) were born to mothers who had at least two prescriptions for acetaminophen during pregnancy. Among all the children, 1% were diagnosed with autism and 6% with ADHD. Children whose mothers used Tylenol during pregnancy had about a 12% higher relative risk of ADHD and a 6% higher relative risk of autism compared to unexposed children. However, when the researchers compared siblings, the link between fetal Tylenol exposure and both ADHD and autism disappeared.

  • The study analyzed births in Taiwan between 2004 and 2015.

The players

Zeyan Liew

An associate professor of epidemiology at the Yale School of Public Health in New Haven, Connecticut and a co-author of the study.

Jeremy M. Veenstra-VanderWeele

A professor and autism researcher at Columbia University Irving Medical Center in New York City who was not involved in the study.

Cynthia Gyamfi-Bannerman

A professor of maternal-fetal medicine in the obstetrics and gynecology department at UC San Diego Health Sciences and past president of the Society for Maternal-Fetal Medicine, who was not involved in the study.

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What they’re saying

“The take-home message seems to be that there is not an association between acetaminophen exposure and autism or ADHD risk, at least when appropriately controlling for other factors.”

— Jeremy M. Veenstra-VanderWeele, Professor and autism researcher (N/A)

“Any shared underlying risk factors between the siblings will be controlled for in the study design, which is a strength.”

— Zeyan Liew, Associate professor of epidemiology (N/A)

“The bottom line is that these data, while interesting, would not change the current recommendation on Tylenol use in pregnancy.”

— Cynthia Gyamfi-Bannerman, Professor of maternal-fetal medicine (N/A)

The takeaway

This large study provides more evidence that there may not be a direct causal link between prenatal acetaminophen exposure and neurodevelopmental conditions like ADHD and autism. The findings suggest other maternal health factors or environmental influences could be responsible for any small increased risks, reinforcing the importance of controlling for these underlying factors when studying medication use during pregnancy.