Headache? Sore back? Bad cold? In the past, many Americans would reach into their medicine cabinets and pull out acetaminophen, known by the brand-name Tylenol, without any concern at all. It's long been a staple of home medicine, seen as a safe way to treat pain and fever in pregnancy as well as in childhood, when used as directed. But President Trump has come out swinging against this common over-the-counter drug, blaming it for rising cases of autism in recent years.
"Don't take Tylenol if you're pregnant, and don't give Tylenol to your child," Trump said in a White House briefing, emphatically repeating this warning more than a dozen times. "Fight like hell not to take it."
Physician groups, plus the maker of Tylenol, immediately pushed back on the president's stance, saying it just wasn't supported by the research — and could have serious repercussions for women and babies.
All of this means that many parents and would-be parents, plus others who sometimes take acetaminophen, are suddenly wondering what they should think about this old mainstay of medicine, and whether they truly need to be concerned.
What have research studies actually found?
Researchers have spent years trying to tease out any links between autism and acetaminophen, but the evidence is uncertain, according to the Food and Drug Administration's new warning sent to physicians. It noted that while some studies have found an association between use of this drug and development of autism in children, other studies have come to the opposite conclusion.
One reason such research is difficult is that parents may not remember, or may misreport, how much of the drug they actually took during pregnancy. That's why researchers were particularly interested in one 2019 study in the journal JAMA Psychiatry that made objective measurements of drug levels in umbilical cord blood in nearly a thousand mother-and-child pairs. It found that children with the highest levels of acetaminophen in their cord blood were roughly three times more likely to be diagnosed with autism or ADHD later on, compared with kids that had the lowest levels in their cord blood. However, the lead researcher was careful to note that the study did not show that the drug caused those disorders — just that there was an association.
Another influential study, one of the largest and best controlled, was published in 2024, and it analyzed the records of over two million children in Sweden. It initially found a small link between acetaminophen use in pregnancy and autism. But the researchers knew that genes have a powerful effect on autism risk, and they wanted to control for this. Since siblings share genes and also other commonalities such as the same home environment, they did an analysis that compared siblings who had been exposed to acetaminophen with those who had not. And when they did that, the link between autism and acetaminophen disappeared.
"In other words, the association was not a causal one, and it was most likely due to other factors like genetics, infections, fevers, that sort of thing," Brian Lee of Drexel University, one of the study's authors, said in an interview with NPR's Allison Aubrey.
So far, he says, the evidence largely suggests that acetaminophen does not cause autism.
"I wouldn't say that the chapter is closed on this by any means, but certainly the mound of evidence from the best studies to date points to no causal effect of acetaminophen on autism."
One researcher whose work has suggested that the drug may increase the risk of autism is epidemiologist Ann Bauer of the University of Massachusetts. She told NPR's Jon Hamilton that the "case is still open" on acetaminophen. She thinks that while expectant parents should be told about a potential risk, they should also be told there's real uncertainty about that risk.
She also thinks it's too soon for the government to be offering guidance on the use of this drug and how that might be related to autism.
"I think they may be jumping the gun," she said. "I think those of us in the research community would like to see stronger evidence."
Why not just avoid Tylenol altogether in pregnancy?
President Trump said repeatedly that there was "no downside" to not taking acetaminophen and that women should just try to tough it out. But experts in maternal-fetal medicine say that untreated fever is known to be dangerous in pregnancy, and pain is a problem too.
The Society for Maternal-Fetal Medicine has pointed out that "untreated fever, particularly in the first trimester, increases the risk of miscarriage, birth defects, and premature birth."
Untreated pain, meanwhile, can be linked to depression and high blood pressure. Nicole Baldwin, MD, a pediatrician from Cincinnati, Ohio, told NPR's Allison Aubrey that "I remember when I was pregnant with my daughter, I had an injury. I fell in mid-pregnancy. And if I hadn't had Tylenol to take, I can't imagine the suffering I would have had for two months."
"There are no other medications that these pregnant women can take," Baldwin said, as other pain and fever reducing drugs have been proven unsafe in pregnancy. Ibuprofen, for example, has been linked to kidney problems in fetuses.
"Acetaminophen is one of the few options available to pregnant patients to treat pain and fever," the American College of Obstetricians and Gynecologists said in a statement following the president's press conference. "When considering the use of medication in pregnancy, it's important to consider all potential risks along with any benefits."
And that's basically what the FDA told physicians this week, saying that while "clinicians should consider minimizing the use of acetaminophen during pregnancy for routine low-grade fevers," this had to be balanced with the fact that acetaminophen is the safest over-the-counter option in pregnancy against fever and pain.
Who should parents trust on these issues?
Worried parents might wonder how they're supposed to make decisions when the research community might debate autism and acetaminophen for years to come.
"Who has time to sit there and go through the dozens or hundreds of scientific articles on any given topic?" sympathizes Lee. "We trust our experts. And if our experts are telling us one thing, but other experts are saying another thing, it causes confusion."
"I would say, what parents need to do is to step back and think about who they are hearing the messages from," Helen Tager-Flusberg, director of Boston University's Center for Autism Research Excellence, told NPR's Michel Martin. "Are they going to listen to people who are not physicians, who have no expertise in autism, or are they going to turn to their medical providers, their treatment providers and ask them what their view of the current science is? That's what they should be doing."
Baldwin, the pediatrician in Cincinnati, likes to explain that any association that's been seen between autism and acetaminophen in studies doesn't necessarily mean there's a causal relationship. Both shark attacks and eating ice cream increase in summer, she says, but that doesn't mean that one causes the other.
"These studies that have been out show correlation, but don't actually show causation," says Baldwin." "And I think that's an important thing for parents to realize — that the science is not known just yet, despite what has been said."
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