What a sweeping new review reveals about Tylenol use during pregnancy
A new analysis published Friday in the medical journal The Lancet Obstetrics, Gynaecology, & Women’s Health, found no evidence that taking acetaminophen during pregnancy significantly increased the risk of children developing autism, attention-deficit/hyperactivity disorder (ADHD) or intellectual disability. The analysis reviewed 43 previously published studies.
Acetaminophen — called paracetamol in many parts of the world — is the active ingredient in over-the-counter fever and pain relievers such as Tylenol. It is the only drug approved during pregnancy to treat fever, which itself has been linked to heightened risks of autism for the developing child.
Late last year, warnings from President Donald Trump, regulatory actions by the Food and Drug Administration, and new lawsuits fueled public concern that acetaminophen raised the risk of neurodevelopmental disorders.
This new study adds to a body of evidence suggesting that if there is any risk linked to acetaminophen use, it is small, Hugh Taylor, the chief of Obstetrics and Gynecology at Yale New Haven Hospital, told Straight Arrow News.
“People should be reassured. Overwhelmingly the data here seems to suggest that acetaminophen is quite safe to use in pregnancy. Certainly by not using it or using alternatives have clear associated risks and harms. We should not be avoiding it and taking on new or even greater risks,” said Taylor, who is also a professor at the Yale School of Medicine.
In 2021, Taylor and 90 other scientists, clinicians and public health professionals published a consensus statement about the potential for acetaminophen use during pregnancy to interfere with fetal development and increase risks of some disorders. Taylor continues to advise his patients to take acetaminophen and any other drug cautiously.
Trump, warning labels and lawsuits
Last September, during a White House briefing, President Donald Trump urged pregnant women to avoid acetaminophen, citing a possible link to autism.
“Don’t take Tylenol. Don’t take it,” Trump said. “Fight like hell not to take it.”
Several health societies immediately pushed back.
“Any association between acetaminophen and autism is based on limited, conflicting and inconsistent science and is premature,” Autism Science Foundation Chief Science Officer Dr. Alycia Halladay said in a press release.
“Decades of research have found that acetaminophen is safe for children when administered as recommended,” the American Academy of Pediatrics wrote in a statement. “Misleading claims that the medicine is not safe and is linked to increased rates of autism send a confusing, dangerous message to parents and expectant parents and does a disservice to autistic individuals.”
The FDA moved to change warning labels on products containing acetaminophen and published a letter to physicians instructing them to consider limiting its use for pregnant women with low-grade fevers.
“The FDA is taking action to make parents and doctors aware of a considerable body of evidence about potential risks associated with acetaminophen,” FDA Commissioner Marty Makary said at the time.
“Even with this body of evidence, the choice still belongs with parents. The precautionary principle may lead many to avoid using acetaminophen during pregnancy, especially since most low-grade fevers don’t require treatment. It remains reasonable, however, for pregnant women to use acetaminophen in certain scenarios.”
In October, Texas Attorney General Ken Paxton sued the makers of Tylenol, claiming the companies ignored and silenced emerging evidence linking the medication with an increased risk of autism and other neurological disorders.
In recent years, parents and concerned citizens have filed hundreds of lawsuits asserting similar claims.
The new study
In their new review study published Friday, researchers from Italy, the U.K., Sweden and Norway identified 43 previous studies that assessed associations between mothers taking acetaminophen during pregnancy and children developing autism, ADHD and intellectual disability. The researchers pooled data from 17 of the highest quality studies to estimate overall risk based on the best available evidence.
Researchers found no significant link between taking acetaminophen during pregnancy and autism, ADHD or intellectual disability. They measured risk using a statistic called an odds ratio, which compares how likely an outcome is between two groups. An odds ratio of 1 means there is no difference.
The odds ratio was 1.03 for autism, 0.97 for ADHD, and 1.11 for intellectual disability. That corresponds to a 3% increase in the odds of autism, a 3% decrease in the odds of ADHD, and an 11% increase in the odds of intellectual disability, but those findings were not statistically significant, meaning the study did not find strong enough evidence to rule out the possibility that the observed difference in odds happened by coincidence.
“This is a well done study,” said Taylor, who was not involved in the research.
The scientists also analyzed data from a subset of sibling studies that compared the risk of neurodevelopmental disorders when one child was exposed to acetaminophen during pregnancy and their sibling was not.
Autism is known to be hereditary, meaning it can be passed from parents to children. One meta-analysis estimated that 60% to 90% of autism risk is genetic.
Sibling studies help control for factors — such as shared genetics, family environment, parental health and socioeconomics — that are difficult to measure but strongly influence child development.
Although only two sibling studies looked at the risk of autism and intellectual disability, while three examined the risk of ADHD, each determined there was no increased risk of any disorder.
“This (study) found no difference. There are others who found some small differences,” Taylor told SAN. “We can’t say that any one is the definitive study but it’s certainly reassuring. Certainly if there was a huge signal that this was really a common consequence of using acetaminophen, Tylenol, it would have shown up in all the studies.”
He continued: “I think we can be reassured that if there is any risk, it is a very low risk.”
The body of evidence
A different review study published by American scientists in August 2025, reported slightly conflicting findings. Researchers identified 46 prior studies that assessed pregnant women’s exposure to acetaminophen and their child’s risk of developing autism and ADHD.
Of those 46 studies, 27 reported a heightened and statistically significant risk, nine showed no association, and four indicated that acetaminophen reduced the risk of neurodevelopmental disorders. The authors noted that they did not pool data from the existing studies to come up with an overall risk score because there was too much variation between the studies for sound comparison.
Importantly, both review papers and all available studies assessing links between acetaminophen use and autism in humans are observational studies. Scientists typically asked pregnant women to recall their acetaminophen use during pregnancy and then collected data, such as an autism diagnosis, on their children.
These types of studies have limitations. For instance, women might misrecall how much or how often they took medications. Clinical diagnoses might differ. Moreover, these types of studies cannot account for every factor that might affect the development of an intellectual or neurodevelopmental disorder. Scientists likely do not even know all the factors that might influence health outcomes.
Experimental studies generate stronger evidence because every variable is tightly controlled. But scientists cannot perform controlled experiments with pregnant women due to ethical concerns and codes. As a result, observational studies, supplemented at times by animal experiments, are often the most reliable evidence available.
“There are some animal studies that do suggest some potential risk, so I don’t think we should dismiss it ever as absolutely completely safe based on any clinical study, which all have their flaws,” Taylor said. “We should always be judicious and never use medication if we don’t really need it.”
A clinician’s guidance to pregnant women
Acetaminophen is the only drug approved to treat fever and pain during pregnancy; other medications such as aspirin and ibuprofen, commonly known as Advil or Motrin, have well-documented impacts on the fetus, according to the FDA. About 65% of women take acetaminophen during pregnancy, according to Taylor.
Fever during pregnancy has itself been linked to an increased risk of autism and ADHD. One study of almost 100,000 Norwegian babies reported that children exposed to maternal fever during the first trimester had 30% higher odds of an ADHD diagnosis. The odds for children born to mothers who had a fever twice or more during the first trimester more than doubled.
Given the body of evidence, Taylor told SAN that he recommends pregnant women use any medication cautiously, weigh the risks and benefits and consult their physician.
“Tylenol is the safest thing we have now to treat some serious conditions in pregnancy and the alternatives have more risk. I’m not changing what I tell my patients,” he said. “I am in agreement with the recommendations from the American College of OBGYN and the American Society of Reproductive Medicine, and other professional societies in the field.”
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Ella Rae Greene, Editor In Chief
