Last week, a federal panel of judges reversed a lower court’s decision to dismiss lawsuits against the manufacturers of Tylenol claiming that use of the drug during pregnancy causes developmental disorders. The ruling threatens to reignite unfounded concerns, amplified by the Trump administration last year, about the ubiquitous over-the-counter medication.
But the question policymakers and the courts should be asking is not whether Tylenol, the brand name for acetaminophen, is safe for pregnant women. It is whether there is a safer alternative. For treating fever and pain, the answer is no.
Much of the concerns about acetaminophen stem from a 2025 review of 46 papers, which suggested an association between Tylenol use during pregnancy and neurodevelopmental conditions such as autism and attention-deficit/hyperactivity disorder. President Donald Trump and Health Secretary Robert F. Kennedy Jr. cited that analysis to bolster their case against the drug. The lead author was also the expert witness for the plaintiffs in the Tylenol lawsuits and has reportedly received at least $150,000 for his testimony.
The review has been heavily criticized for its methodology, specifically because some studies it included did not account for why women took the medication in the first place. Many likely took the drug to treat fever and specific illnesses, which may themselves be associated with developmental outcomes. That makes it difficult to determine whether the elevated risk is due to the medication or the underlying condition it’s meant to treat.
A subsequent review, published in the Lancet in March, attempted to resolve this problem by excluding studies that did not adequately account for these other possible explanations. It found no evidence that acetaminophen use during pregnancy increased the risk of developmental disorders.
The Lancet review also gave greater weight to studies that used a method called sibling-control analysis. By comparing siblings born to the same parents — one exposed to acetaminophen during pregnancy and the other which was not — researchers can account for the genetic characteristics that those siblings share. If acetaminophen caused autism, the exposed child would be expected to have a higher risk.
The pivotal study, published in JAMA in 2024, followed nearly 2.5 million women in Sweden through pregnancy and tracked their children for more than 20 years. The initial analysis found that mothers who took acetaminophen were more likely to have children with neurodevelopmental disorders. But after accounting for genetics and other confounding factors, the association disappeared. Two sibling-control studies published this year — one from Japan and the other from Hong Kong — reached the same conclusion.
Taken together, the scientific evidence does not support the claim that Tylenol is unsafe to use during pregnancy. The next question is whether avoiding it would leave pregnant women better off.
Leaving a fever untreated is certainly not a reasonable alternative. Decades of research have linked prolonged fever during pregnancy to birth defects, including heart defects, abnormalities of the brain and spinal cord, and cleft lip and palate.
Ibuprofen, another over-the-counter fever reducer, is also not an option. During pregnancy, that drug can reduce amniotic fluid and cause kidney problems in the developing baby.
Women also have limited options other than acetaminophen to treat back pain, headaches and other common aches. Opioid pain medications are far more dangerous and can lead to serious complications, including preterm birth and severe withdrawal symptoms in newborns. Meanwhile, recent surveys suggest that pregnant women are increasingly turning to cannabis to treat pregnancy-related symptoms. That, too, is a worrying trend, as marijuana use in pregnancy has been linked to stillbirth and a plethora of learning and behavioral problems in childhood.
If a pregnant woman has a fever, she can use methods to lower her body temperature such as taking a cool bath and drinking cold fluids, but she should not delay taking Tylenol. If she has body aches, she can try nondrug approaches such as stretching, yoga or physical therapy. But if these are not enough, acetaminophen remains one of the safest medications during pregnancy. As with any medication, women should consult their health care provider, follow the directions on the label and use the lowest effective dose for the shortest time necessary.
This is the approach long endorsed by major medical organizations, including the World Health Organization and the American College of Obstetricians and Gynecologists. Unfortunately, the Food and Drug Administration has announced that it plans to require new warning labels about possible neurodevelopmental risks. The revival of the litigation only muddies the waters further, as scientific evidence will be weighed in courtrooms rather than by medical organizations.
In the meantime, confused patients and families might delay treating fevers or turn to unproven alternatives. The worst outcome would be for one of the best-studied medications in pregnancy to be replaced by alternatives whose safety is far less certain. If the goal is to reduce pregnancy complications and improve the health of women and children, casting doubt on acetaminophen is every bit as misguided as eroding trust in vaccines.
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