Is there a correlation between acetaminophen (Tylenol) use during pregnancy and the risk of autism spectrum disorder in offspring?

Acetaminophen Use During Pregnancy and Autism Risk

Current guidelines indicate that the weight of evidence is inconclusive regarding a causal relationship between acetaminophen use during pregnancy and autism spectrum disorder in offspring, though prolonged use may be associated with increased risk. 1

Current Evidence and Recommendations

The Society for Maternal-Fetal Medicine (SMFM) and the American College of Obstetricians and Gynecologists (ACOG) continue to recommend acetaminophen as a reasonable and appropriate medication choice for treating pain and fever during pregnancy 1. However, several important considerations should guide clinical decision-making:

Association with Neurodevelopmental Outcomes

• Multiple studies have found associations between maternal acetaminophen use during pregnancy and increased risk of neurodevelopmental disorders, including autism spectrum disorder (ASD) 1, 2
• A Danish national birth cohort study found that prenatal acetaminophen use was associated with an increased risk of ASD accompanied by hyperkinetic symptoms (HR = 1.51,95% CI 1.19-1.92) 3
• Longer duration of use appears to increase risk:
  • Use for >20 weeks in gestation may increase the risk of ASD with hyperkinetic symptoms almost twofold 3
  • Use for ≥28 days is associated with a higher risk (RR = 1.63) 1

Strength and Limitations of Evidence

Recent research using the Navigation Guide methodology (2025) found that the majority of higher-quality studies report positive associations between prenatal acetaminophen use and neurodevelopmental disorders 2. However, important limitations exist:

• The conditions requiring acetaminophen (fever, inflammation) may themselves contribute to neurodevelopmental outcomes 1
• Studies show heterogeneity in outcomes, with some focusing on ASD with hyperkinetic features rather than ASD alone 4, 3
• Some research suggests the predisposition may be toward hyperkinetic syndrome rather than autism specifically 4

Clinical Guidance

When to Use Acetaminophen in Pregnancy

• Acetaminophen remains the safest medication option for necessary pain or fever relief during pregnancy 1, 5
• Use the lowest effective dose for the shortest possible time 1, 5
• Avoid prolonged use (>28 days) without periodic evaluation of continued need 1
• Exercise particular caution with use in second and third trimesters 1

Risk Mitigation Strategies

• Consider non-pharmacological approaches for mild to moderate pain when appropriate 1
• For fever, which can itself pose risks during pregnancy, appropriate treatment remains important 1, 5
• When acetaminophen is needed, limit duration of use, particularly avoiding extended use beyond 20 weeks gestation 1, 3

Common Pitfalls to Avoid

1. Avoiding necessary treatment: Untreated pain or fever may pose greater risks to pregnancy than judicious acetaminophen use 1, 5

2. Extended use without reassessment: Continuing acetaminophen for extended periods without evaluating ongoing need increases potential risk 1

3. Misinterpreting association as causation: The relationship between acetaminophen and neurodevelopmental outcomes may be confounded by the conditions requiring treatment 1

4. Overlooking dose and duration effects: Risk appears to increase with longer duration and higher doses, suggesting these factors should guide clinical decisions 1, 3

While research continues to evolve in this area, current guidelines support judicious use of acetaminophen during pregnancy when clinically indicated, with attention to minimizing duration of exposure.