A comprehensive scientific review has concluded that taking acetaminophen, known as Tylenol, during pregnancy does not increase the risk of autism, ADHD, or intellectual disability in children. Led by researchers at City St George's, University of London, the study analyzed 43 high-quality studies, including sibling comparisons to isolate medication effects from genetic and environmental factors. The findings, published on January 16, 2026, in The Lancet Obstetrics, Gynaecology & Women's Health, address earlier concerns sparked by less robust research.
The review, a systematic analysis and meta-analysis, examined data from over 1 million children across various studies. Specifically, it assessed outcomes for 262,852 children for autism, 335,255 for ADHD, and 406,681 for intellectual disability. Using sibling comparisons—where one child was exposed to acetaminophen in utero and another was not—the researchers found no elevated risks compared to unexposed pregnancies. This method helps control for shared genetics and family environments that could confound results.
Public concern had grown following claims in September 2025 linking prenatal acetaminophen to brain development issues and higher autism rates. However, prior studies often suffered from limitations like incomplete data or failure to account for family history. The new analysis prioritized high-quality evidence, evaluating studies with the Quality In Prognosis Studies (QUIPS) tool to minimize bias. Results held firm even in low-bias studies tracking children beyond five years.
Professor Asma Khalil, who led the study as Professor of Obstetrics and Maternal Fetal Medicine at City St George's, University of London, explained the implications. "Our findings suggest that previously reported links are likely to be explained by genetic predisposition or other maternal factors such as fever or underlying pain, rather than a direct effect of the paracetamol itself," she said. She added, "The message is clear—paracetamol remains a safe option during pregnancy when taken as guided. This is important as paracetamol is the first-line medication we recommend for pregnant women in pain or with a fever, and so they should feel reassured that they still have a safe option to relieve them of their symptoms."
While the review aligns with global medical guidelines, it noted gaps in data on exposure by trimester, child sex, or dosage frequency due to insufficient reporting in sibling studies. Untreated pain or fever during pregnancy poses its own risks, reinforcing the value of acetaminophen as a first-line treatment when used properly.
