Is there a link between Tylenol (acetaminophen) use and the risk of autism?

Acetaminophen Use and Autism Risk: Current Evidence

Based on the most recent high-quality evidence, acetaminophen use during pregnancy is not associated with an increased risk of autism spectrum disorder in offspring when accounting for familial confounding factors. 1

Evidence Overview and Recommendations

Current Guidelines and Position Statements

• The Society for Maternal-Fetal Medicine (SMFM) and American College of Obstetricians and Gynecologists (ACOG) consider acetaminophen a reasonable and appropriate medication choice for pain and fever relief during pregnancy 2
• These organizations emphasize that the weight of evidence is inconclusive regarding a possible causal relationship between acetaminophen use and neurodevelopmental disorders 2

Latest Research Findings

• The most recent high-quality evidence from a 2024 nationwide cohort study with sibling control analysis of 2.48 million children found:
  • No association between prenatal acetaminophen exposure and autism (HR 0.98,95% CI 0.93-1.04) when controlling for familial factors 1
  • No evidence of a dose-response relationship between acetaminophen exposure and autism risk 1
  • Initial associations observed in models without sibling controls disappeared when accounting for familial confounding 1

Earlier Research and Conflicting Evidence

• Earlier studies suggested potential associations:
  • A Danish National Birth Cohort study (2016) found increased risk of ASD with hyperkinetic symptoms (HR 1.51,95% CI 1.19-1.92) with prenatal acetaminophen use 3
  • Longer duration of use (>20 weeks) appeared to increase risk in some studies 2, 3
• A 2025 review using the Navigation Guide methodology reported that higher-quality studies were more likely to show positive associations between prenatal acetaminophen use and neurodevelopmental disorders 4

Clinical Application

Recommendations for Pregnant Women

• Acetaminophen remains the preferred analgesic and antipyretic during pregnancy 2
• Use the lowest effective dose for the shortest possible time 2
• Consider non-pharmacological approaches for mild to moderate pain when appropriate 2
• Avoid prolonged use without periodic evaluation of continued need 2

Important Considerations

• Untreated pain or fever during pregnancy may pose greater risks than judicious acetaminophen use 2
• The conditions requiring acetaminophen (fever, inflammation) may themselves contribute to neurodevelopmental outcomes 2

Common Pitfalls to Avoid

• Misinterpreting ecological or observational studies that don't account for familial confounding factors
• Failing to consider that earlier positive associations may be explained by confounding variables
• Causing unnecessary anxiety by overstating risks when the highest quality evidence does not support a causal link
• Avoiding necessary treatment of pain or fever during pregnancy, which could pose greater risks to both mother and fetus

When counseling patients about acetaminophen use during pregnancy, emphasize that the most rigorous recent evidence does not support a causal link to autism when accounting for familial factors, while acknowledging that judicious use remains the prudent approach.