Is there an association between acetaminophen (Tylenol) use during pregnancy and the development of autism?

Acetaminophen Use During Pregnancy and Autism Risk

The weight of evidence is inconclusive regarding a causal relationship between acetaminophen use during pregnancy and autism spectrum disorder in offspring, and acetaminophen remains the safest medication choice for treating pain and fever during pregnancy. 1

Current Evidence and Guidelines

The Society for Maternal-Fetal Medicine (SMFM) and the American College of Obstetricians and Gynecologists (ACOG) have reviewed the available evidence and recommend that acetaminophen be considered a reasonable and appropriate medication choice for treating pain and/or fever during pregnancy 1. This recommendation is based on:

• The inconclusive nature of current evidence regarding a causal link between prenatal acetaminophen exposure and neurodevelopmental disorders
• The recognition that untreated pain or fever may pose greater risks to both mother and fetus
• The lack of safer alternative medications for pain and fever management during pregnancy

Research Findings

The research on this topic shows mixed results:

• A 2024 study published in JAMA found that acetaminophen use during pregnancy was not linked to autism, ADHD, or intellectual disability in offspring 2

• Earlier studies have reported associations between maternal acetaminophen use during pregnancy and increased risk of neurodevelopmental disorders, including ASD with hyperkinetic disorder (hazard ratio of 1.51) 3

• A Danish national birth cohort study found that longer duration of use (>20 weeks in gestation) may increase the risk of ASD with hyperkinetic symptoms almost twofold 3

• A 2025 systematic review using the Navigation Guide methodology reported that the majority of studies showed positive associations between prenatal acetaminophen use and neurodevelopmental disorders 4

Important Considerations

Confounding Factors

A critical consideration is that the conditions requiring acetaminophen treatment (fever, inflammation) may themselves contribute to neurodevelopmental outcomes 1. This makes it difficult to determine whether any observed associations are due to the medication itself or the underlying condition being treated.

Duration of Use

Multiple studies suggest that longer duration of use may be associated with higher risk. Prenatal exposure for ≥28 days has been associated with a higher risk of neurodevelopmental issues 1, and use for >20 weeks in gestation may increase the risk of ASD with hyperkinetic symptoms 3.

Clinical Recommendations

1. Acetaminophen remains the safest medication option for necessary pain or fever relief during pregnancy 1

2. Use acetaminophen at the lowest effective dosage and for the shortest time possible 5

3. Consider non-pharmacological approaches for mild to moderate pain when appropriate 1

4. Exercise particular caution with prolonged use, especially in second and third trimesters 1

5. Avoid prolonged use without periodic evaluation of continued need 1

Common Pitfalls to Avoid

• Withholding necessary treatment: Untreated pain or fever may pose greater risks to both mother and fetus than acetaminophen use 1, 5

• Extended use without reassessment: Prolonged use without periodic evaluation may increase risk of adverse outcomes 1

• Failure to consider alternative approaches: Non-pharmacological approaches should be considered for mild to moderate pain when appropriate 1

• Overlooking the underlying condition: The conditions requiring acetaminophen (fever, inflammation) may themselves contribute to neurodevelopmental outcomes 1

In summary, while some studies suggest a possible association between prenatal acetaminophen exposure and neurodevelopmental disorders, the evidence is not conclusive enough to establish causality. Healthcare providers should discuss the risks versus benefits with patients, emphasizing judicious use of acetaminophen when clinically indicated.