New BMJ Analysis Finds Insufficient Evidence Linking Prenatal Acetaminophen Use to Autism or ADHD

A comprehensive review published Sunday in the BMJ reports no clear causal connection between acetaminophen use during pregnancy and later diagnoses of autism spectrum disorder or attention-deficit/hyperactivity disorder in offspring. The findings arrive two months after President Donald Trump publicly warned that taking the over-the-counter pain reliever while expecting “was associated with a very increased risk of autism.”

The research team, drawn from institutions in the United Kingdom, Spain and Australia, evaluated nine previously published systematic reviews encompassing 40 individual studies on maternal acetaminophen exposure and child neurodevelopment. Although the earlier reviews had noted a potential association, seven of the nine explicitly advised against inferring causality. After assessing methodology, the authors of the new paper rated every one of the nine reviews as having “low” or “critically low” confidence, citing limited search strategies, incomplete reporting of excluded studies, design inaccuracies and use of non-standard tools for measuring bias.

Dr. Shakila Thangaratinam, executive dean at the University of Liverpool’s Institute of Life Course and Medical Sciences and a co-author of the analysis, said the project was undertaken partly in response to the president’s September statements. During a White House news conference that month, Trump advised pregnant women to avoid the medication entirely and questioned its use in infants, positions he later repeated on social media.

In August, federal officials had referenced a separate meta-analysis led by researchers at the Icahn School of Medicine at Mount Sinai, Harvard T.H. Chan School of Public Health, UCLA Fielding School of Public Health and the University of Massachusetts Lowell. That paper suggested prenatal exposure “may be associated” with higher rates of autism and ADHD, fueling debate about the drug’s safety. Acetaminophen, also known as paracetamol, is widely recommended to manage pain and fever during pregnancy because alternatives such as non-steroidal anti-inflammatory drugs carry documented risks for the fetus.

The new BMJ review highlights several limitations in the existing literature. Only one of the nine systematic reviews included studies that controlled for shared familial factors through sibling comparisons. When those analyses adjusted for genetics and common environmental influences, any link between prenatal acetaminophen use and neurodevelopmental disorders disappeared. The authors conclude that observed associations in previous work are likely driven by unmeasured genetic, familial or environmental variables rather than the medication itself.

Major U.S. medical organizations have pushed back on recent public warnings. The American College of Obstetricians and Gynecologists called the suggestion of a proven link “irresponsible” and “not backed by the full body of scientific evidence.” Clinicians expressed concern that pregnant patients could forego treatment for high fever or severe pain, conditions that can endanger both parent and fetus. They also noted the possibility that patients might turn to ibuprofen or other non-recommended drugs if acetaminophen is avoided.

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The debate has extended beyond the medical community. Last month, the Texas attorney general filed a lawsuit against manufacturers of Tylenol, alleging the companies concealed information about possible neurodevelopmental risks. Legal proceedings remain in their early stages.

Thangaratinam and colleagues argue that the controversy illustrates a broader gap in pharmaceutical research. Pregnant individuals are frequently excluded from clinical trials, leaving few medications with robust safety data for this population. The authors call for targeted drug discovery and rigorous studies that include expectant participants so practitioners can make evidence-based recommendations.

Until larger, methodologically sound investigations are available, the review advises clinicians and patients to weigh the known benefits of acetaminophen—particularly its role in controlling fever—against the absence of demonstrated harm. Additional background on medication use during pregnancy can be found on the U.S. Food and Drug Administration’s informational page (FDA).

Crédito da imagem: Jorge Martinez/Getty Images