Acetaminophen in Pregnancy: The Autism Link Fades in the Strongest Studies

Researchers at the University of Santiago de Compostela have pooled seven earlier meta-analyses covering more than 3 million participants, and report that the small association between acetaminophen use in pregnancy and later autism or ADHD diagnoses does not hold up when only the higher-quality evidence is counted. Restricted that way, the estimates shrink substantially and in several models approach zero.

The paper appeared Sept. 23 in Developmental Medicine & Child Neurology. Its authors write that the existing evidence from population studies does not support a robust causal link, and that acetaminophen, or paracetamol, remains an appropriate first-line treatment during pregnancy when clinically indicated.

The work is a registered umbrella review, meaning it pools other reviews rather than individual studies. Pooled with no restriction on quality, the seven meta-analyses gave risk ratios just above one: 1.17 for autism and 1.29 for ADHD. Both figures fell substantially once the team counted only the stronger reviews and the primary studies it judged to be at low risk of bias.

The authors say the associations are probably influenced by weaknesses in the underlying research: families that use the drug can differ in other ways the original studies did not measure, and records of who actually took it are imprecise.

The review also reports that the pooled studies disagreed with one another and that they draw on many of the same primary studies. The searches ran up to November 2025.