Recent discussions and media reports have raised questions about whether taking acetaminophen (commonly known as Tylenol) during pregnancy may increase the risk of autism in children. As an organization dedicated to autism research and resources, we want to clarify what the research actually shows.
No Proven Cause-and-Effect
To date, there is no evidence of a proven causal link between acetaminophen use during pregnancy and autism. Some studies, including those summarized in a recent review and a 2025 article analyzing 46 studies, have observed a potential association or slightly increased risk. However, it is critical to understand that an association — or even a small increased risk — is very different from causation. Current research does not support the conclusion that acetaminophen causes autism.
The Research History
The earliest studies investigating this potential link date back to 1987, though most research has emerged over the last decade. This line of inquiry has largely grown out of a broader effort to explore environmental factors that might help explain the observed increase in reported autism spectrum disorder (ASD) rates, rather than being sparked by any single event.
Scope and Quality of Studies
The review referenced above identified 46 studies examining acetaminophen use during pregnancy and neurodevelopmental outcomes, including autism and ADHD. Slightly more than half of these studies observed a minimal association, while others found no evidence of increased risk.
Importantly, study methodology matters: larger studies with well-controlled designs provide the most reliable evidence. For example, Ahlqvist et al. (2024), a recent study with strong methodology, found no evidence for an association or increased risk.
Why This Matters
It’s important to understand the difference between association and causation. Just because two things appear together in some studies does not mean one causes the other.
Current evidence simply does not support the idea that acetaminophen use during pregnancy leads to autism.
Looking Ahead
Research into potential environmental influences on autism continues, and scientists remain committed to understanding all factors that may impact neurodevelopment. However, based on the best available evidence, expecting parents can be reassured that occasional acetaminophen use during pregnancy has not been proven to cause autism.
For further reading on this topic, see Politifact’s coverage and the recent peer-reviewed studies, including Ahlqvist (2024).