Acetaminophen Use and Autism Risk
Based on the most recent and highest quality evidence, prenatal acetaminophen use is not associated with an increased risk of autism spectrum disorder in children when accounting for familial factors. 1
Current Evidence on Acetaminophen and Neurodevelopmental Outcomes
Most Recent Evidence (2024)
The most recent nationwide cohort study with sibling control analysis of nearly 2.5 million children found:
When accounting for familial confounding factors through sibling control analysis, acetaminophen use during pregnancy showed no association with:
No dose-response relationship was observed in sibling control analyses 1
Previous Concerns and Earlier Studies
Earlier research had suggested potential associations:
A 2016 Danish National Birth Cohort study found an association between prenatal acetaminophen use and ASD with hyperkinetic symptoms (HR 1.51,95% CI 1.19-1.92), particularly with longer duration of use (>20 weeks) 2, 3
Several ecological and observational studies raised concerns about potential links between acetaminophen exposure and neurodevelopmental outcomes 4, 5
Clinical Guidance
The Society for Maternal-Fetal Medicine (SMFM) and American College of Obstetricians and Gynecologists (ACOG) recommend:
Acetaminophen remains a reasonable and appropriate medication choice for pain and fever relief during pregnancy 3
Use the lowest effective dose for the shortest possible time 3
Consider non-pharmacological approaches for mild to moderate pain when appropriate 3
Important Clinical Considerations
Safety Parameters
- Maximum daily dose: 4g (preferably limit to 3g or less to reduce hepatic toxicity risk) 3
- Limit to 325mg per dosage unit in prescription products 3
- Avoid combining with other acetaminophen-containing products 3
Common Pitfalls to Avoid
Confounding by indication: Earlier studies showing associations may have been influenced by the conditions requiring acetaminophen rather than the medication itself
Familial confounding: The most recent and methodologically robust study using sibling controls found no association, suggesting previous positive findings may have been due to unmeasured familial factors 1
Overdosing: Be vigilant about total daily acetaminophen intake, especially from multiple products
Clinical Decision Making
When considering acetaminophen use during pregnancy:
- Weigh benefits for maternal pain/fever relief against potential risks
- Use the lowest effective dose for the shortest duration
- Consider that the most recent high-quality evidence does not support concerns about autism risk when accounting for familial factors 1
- Recognize that untreated pain or fever may pose risks to both mother and fetus
The weight of current evidence, particularly the most recent sibling-controlled study, is reassuring regarding acetaminophen use during pregnancy and autism risk.