Major Study Finds No Link Between Acetaminophen in Pregnancy and Autism Risk
One of the largest studies ever conducted on the subject has concluded that taking acetaminophen during pregnancy does not increase the risk of autism in children. The research, analyzing data from over 1.5 million Danish children, found only a minimal three percent higher risk in the general population—a difference that was not statistically significant.
Comprehensive Analysis and Sibling Comparison
Researchers from Copenhagen University Hospital Rigshospitalet conducted this nationwide cohort study, published in JAMA Pediatrics. They examined children born in Denmark between 1997 and 2022, using national prescription records to identify mothers who filled acetaminophen prescriptions during pregnancy. The study specifically tracked prescription acetaminophen ordered by doctors, though it could not monitor over-the-counter purchases, which represent the most common method of obtaining the drug.
Children were followed from age one until July 2023 or until they received an autism diagnosis. The team adjusted for numerous confounding factors, including maternal age, income, smoking habits, other medications, and underlying health conditions. Even after these adjustments, no meaningful association emerged.
Among the 1.5 million children studied, just over 31,000 were exposed to acetaminophen in the womb. In this exposed group, 1.8 percent were later diagnosed with autism, compared to three percent in the unexposed group. However, this difference disappeared entirely after accounting for confounding variables.
Sibling Analysis Reinforces Findings
To further strengthen their conclusions, researchers performed a sibling analysis, comparing families where a mother took acetaminophen during one pregnancy but not another. Since siblings share genetics, household environment, and socioeconomic factors, any difference in autism risk would more likely be attributed to the exposure itself.
This sibling analysis found no meaningful association between prenatal acetaminophen exposure and autism incidence. Siblings exposed to the drug in utero were not more likely to develop autism than their unexposed brothers or sisters.
Contradicting Political Statements
The findings directly challenge recent comments from Trump administration health officials, who have suggested a potential link between acetaminophen and neurodevelopmental disorders. In a September 2025 press briefing, Health and Human Services Secretary Robert F. Kennedy Jr. referenced unspecified studies indicating a possible association with autism and ADHD, while President Donald Trump advised pregnant women to avoid Tylenol.
Dr. Kira Philipsen Prahm, lead author of the Danish study, noted that recent political statements and media coverage prompted their investigation. "Given recent concerns, we found it relevant to make a well-performed study to either confirm or refute a potential association," she explained.
The Danish team emphasized that even the upper limit of their statistical model ruled out anything more than a 12 percent increased risk. Their results align with a 2024 Swedish study that also found no causal connection.
Understanding Autism Spectrum Disorder
Autism spectrum disorder (ASD) is typically diagnosed around age five, affecting approximately one in 31 American children. Symptoms range from sensory sensitivities to more debilitating speech or intellectual disabilities. Experts in psychology, pediatrics, and genetic medicine contend that ASD is largely genetic, with an estimated 60 to 90 percent of risk being hereditary.
The rise in autism diagnoses—from 1 in 150 children in 2000 to 1 in 31 today—is primarily attributed to improved identification and expanded diagnostic criteria, now including milder forms like Asperger’s syndrome. While some experts speculate about a small real increase due to factors like older parental age, the scientific debate remains open.
Current Medical Advice Remains Unchanged
Despite political skepticism, medical experts and organizations continue to affirm that acetaminophen use during pregnancy is safe when used as directed. A 2025 review of past research suggested a possible link but did not prove causation, advising pregnant women to use the drug at the lowest effective dose for the shortest duration possible.
For now, expectant mothers are advised to follow existing guidelines: acetaminophen remains a safe option for managing fevers and pain during pregnancy, with no significant evidence linking it to increased autism risk.
