Studies find no autism link from acetaminophen use during pregnancy

Three large studies from Sweden, Denmark and Hong Kong found no sign that acetaminophen use during pregnancy raises the risk of autism, even as political warnings pushed some pregnant patients to change how they used the medicine. The clearest data come from a Swedish nationwide cohort published online in JAMA on April 9, 2024, which followed 2,480,797 children born from 1995 to 2019 and found no association in sibling-control analyses.

In that Swedish study, 185,909 children, or 7.49 percent of the cohort, were exposed to acetaminophen during pregnancy. When researchers compared siblings, the hazard ratio for autism was 0.98, a result that did not show increased risk. The same analysis also found no association with ADHD or intellectual disability, adding to a growing body of evidence that has not supported a causal link between prenatal acetaminophen exposure and neurodevelopmental disorders.

Two more studies reinforced that conclusion this year. A JAMA research letter published in May 2026 examined 1.5 million children in Denmark born from 1997 to 2022 and found no association between prenatal acetaminophen use and autism. A June 29, 2026 study in JAMA Internal Medicine, drawing on electronic health records from Hong Kong from 2001 to 2023 and more than 700,000 mother-child pairs, likewise found no link between prenatal exposure and autism or ADHD. That Hong Kong analysis found no difference by trimester, dose, or recommended frequency.

The medical record now sits against a louder political one. In September 2025, Donald Trump and Robert F. Kennedy Jr. appeared at the White House and warned pregnant women against Tylenol despite the lack of conclusive scientific evidence. Tylenol use dropped during pregnancy after those claims, showing how quickly fear can change behavior even when the research does not support the alarm.

Federal regulators later moved in the same direction. On September 22, 2025, the Food and Drug Administration announced it was starting a label change for acetaminophen products and notifying physicians about a possible association with autism and ADHD, while also saying a causal relationship had not been established. The agency noted that acetaminophen remains the only over-the-counter drug approved to treat fevers during pregnancy, and that high fevers themselves can pose risks.

Obstetric guidance has continued to emphasize restraint over panic. The American College of Obstetricians and Gynecologists still describes acetaminophen as the first and safest choice for fever or pain relief during pregnancy. Autism prevalence has risen sharply in the public conversation, from 1 in 150 8-year-olds in 2000 to 1 in 31 in April 2025, based on CDC surveillance data from 16 sites across 15 states and territories, but scientists say much of that increase reflects better screening, diagnostic changes, greater awareness and improved access to services.