Current evidence does not show that Tylenol (acetaminophen) causes autism.
While some preliminary observational studies have suggested a statistical association between prenatal acetaminophen exposure and neurodevelopmental conditions, larger, more rigorous studies have found no evidence of a causal link.
While some preliminary observational studies have suggested a statistical association between prenatal acetaminophen exposure and neurodevelopmental conditions, larger, more rigorous studies have found no evidence of a causal link.
Major health organizations continue to consider acetaminophen safe for use during pregnancy when taken as directed.
Why causation is not established
The main reason a causal link has not been proven is that "association" does not equal "causation".
- Controlling for confounding factors: The strongest recent evidence comes from a 2024 study of nearly 2.5 million children in Sweden. It replicated a weak association between prenatal acetaminophen exposure and autism, but that association completely disappeared after researchers controlled for unobserved factors by comparing full siblings.
- Alternative explanations: The study's authors suggest that the original statistical link may have been caused by familial factors, such as genetics, that influence both the mother's need for pain medication and the child's risk of having autism. Conditions treated by acetaminophen, such as fevers and migraines, have also been independently linked to an increased risk of neurodevelopmental issues.
- Methodological limitations: Many of the earlier observational studies had significant limitations, such as relying on self-reported data from mothers who might be more likely to remember taking the medication if their child later developed autism.
Medical and legal context
Recent debates have brought the issue into public discussion, but the scientific consensus has not changed.
- Ongoing litigation: Hundreds of lawsuits have been filed against manufacturers and retailers of acetaminophen, alleging a failure to warn consumers about the potential risks of using the medication during pregnancy.
- Judicial dismissal: In August 2024, a federal judge dismissed all federal claims in the multi-district litigation, ruling that the plaintiffs' scientific experts failed to provide credible evidence of a link between prenatal acetaminophen use and autism or ADHD. The plaintiffs are appealing this decision.
- Uncertainty and caution: While no causal link has been found, some medical experts suggest that because a definitive answer is not possible, acetaminophen should still be used judiciously—at the lowest effective dose for the shortest possible time, which is the standard advice for any medication used during pregnancy.
The risks of not treating fever
Major health organizations emphasize that not treating conditions like fever and severe pain during pregnancy carries its own serious risks for the mother and child. These risks include miscarriage, birth defects, and premature birth.
