A recent comprehensive review has determined that taking Tylenol during pregnancy does not elevate the risk of developing autism, ADHD, or intellectual disabilities, countering claims promoted by the Trump administration.

Last year, former President Donald Trump cautioned against the use of Tylenol, suggesting a possible but unproven link to autism, advising expectant mothers to avoid the medication.

The new analysis, featured in The Lancet Obstetrics, Gynecology & Women’s Health, evaluated 43 studies and concluded that the most reliable ones, such as sibling comparison studies, strongly support that the medication—known as paracetamol outside the U.S.—is not associated with autism, ADHD, or intellectual disabilities.

Dr. Asma Khalil, the lead researcher, assures, “It is safe to use during pregnancy,” and continues to advocate for its use as a primary treatment for pain or fever in pregnant women.

Although some research has hinted at a potential association between Tylenol use during pregnancy and autism, the majority of studies do not support this connection.

A previous review published in the BMJ highlighted the lack of evidence connecting the use of the drug during pregnancy with autism or ADHD. Additionally, a study in the Journal of the American Medical Association found no association between Tylenol use and the risk of autism, ADHD, or intellectual disabilities in children, based on sibling analysis.

But the White House has focused on research supporting a link.

One of the papers cited on its web page, published in BMC Environmental Health last year, analyzed results from 46 previous studies and found that they supported evidence of an association between Tylenol exposure during pregnancy and increased incidence of neurodevelopmental disorders. Researchers noted that the drug is still important for treating pain and fever during pregnancy, but said steps should be taken to limit its use.

Some health experts have raised concerns about that review and the way Trump administration officials portrayed it, pointing out that only a fraction of the studies focus on autism and that an association doesn’t prove cause and effect. Khalil, a fetal medicine specialist at St. George’s Hospital, London, said that review included some studies that were small and some that were prone to bias.

The senior author of that review was Dr. Andrea Baccarelli, dean of the faculty at Harvard T.H. Chan School of Public Health, who noted in the paper that he served as an expert witness for plaintiffs in a case involving potential links between acetaminophen use during pregnancy and neurodevelopmental disorders. Baccarelli did not respond to an email seeking comment on his study.

Overall, Khalil said, research cited in the public debate showing small associations between acetaminophen and autism is vulnerable to confounding factors. For example, a pregnant woman might take Tylenol for fevers, and fever during pregnancy may raise the risk for autism. Research can also be affected by “recall bias,” such as when the mother of an autistic child doesn’t accurately remember how much of the drug she used during pregnancy after the fact, Khalil said.

When researchers prioritize the most rigorous study approaches – such as comparing siblings to account for the influence of things like genetics – “the association is not seen,” she said.

Genetics are the biggest risk factor for autism, experts say. Other risks include the age of the child’s father, preterm birth and whether the mother had health problems during pregnancy.

In a commentary published with the latest review, a group of researchers who weren’t involved — from the London School of Hygiene and Tropical Medicine, Children’s Hospital Colorado and elsewhere —cautioned that discouraging the use of acetaminophen during pregnancy could lead to inadequate pain or fever control. And that may hurt the baby as well as the mother. Untreated fever and infection in a pregnant woman poses “well-established risks to fetal survival and neurodevelopment,” they said.

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