Trump ties autism to Tylenol use in pregnancy despite inconclusive scientific evidence

U.S. Health and Human Services Secretary Robert F. Kennedy Jr., joined by President Donald Trump, delivers an announcement on “significant medical and scientific findings for America’s children” in the Roosevelt Room of the White House on Sept. 22, 2025 in Washington, D.C.  (Photo by Andrew Harnik/Getty Images)

WASHINGTON — President Donald Trump announced Monday that his administration believes it’s found one contributing factor of autism and a possible treatment, though experts have said such claims are inconclusive and not backed by scientific evidence.

Trump and officials from his administration said during a press conference the Food and Drug Administration will move to update the label on Tylenol, also called acetaminophen, to reflect their concerns that it could potentially be one of the environmental causes of autism. Numerous medical organizations and the manufacturer say there is no proven link.

The FDA will also publish a notice in the Federal Register to change the label on leucovorin, a pharmaceutical intended to counteract the negative effects of certain cancer medications, so that doctors can prescribe it as a potential treatment for autism. 

“They are strongly recommending that women limit Tylenol use during pregnancy unless medically necessary,” Trump said. “That’s, for instance, in cases of extremely high fever that you feel you can’t tough it out. You can’t do it. I guess there’s that.”

Health and Human Services Secretary Robert F. Kennedy Jr. said the FDA “is responding to clinical and laboratory studies that suggest a potential association between acetaminophen use during pregnancy and adverse neurodevelopmental outcomes, including later diagnosis for ADHD and autism.”

Kennedy noted, however, that the FDA recognizes that Tylenol “is often the only tool for fevers and pain in pregnancy, as other alternatives have well documented adverse effects. 

“HHS wants, therefore, to encourage clinicians to exercise their best judgment in the use of acetaminophen for fevers and pain in pregnancy by prescribing the lowest effective dose for the shortest necessary duration and only when treatment is required.”

Kennedy, an environmental lawyer with no medical or research training, said in April the department will shift its research into autism toward potential environmental causes, and pledged to have “some of the answers by September.”

‘Not a single reputable study’

Trump and Kennedy’s announcement was met with deep skepticism. 

Alison Singer, president of the Autism Science Foundation, wrote in a statement released Monday that she’s “unsure why this announcement came today and how the conclusions were drawn.”

“No new data or scientific studies were presented or shared. No new studies have been published in the literature. No new presentations on this topic were made at scientific or medical conferences,” Singer wrote. “Instead, President Trump talked about what he thinks and feels without offering scientific evidence. He said ‘tough it out,’ meaning don’t take tylenol or give it to your child. It took me straight back to when moms were blamed for autism. If you can’t take the pain or deal with a fever, then it’s your fault if your child has autism. That was shocking. Simply shocking.”

American College of Obstetricians and Gynecologists President Dr. Steven J. Fleischman wrote in a statement the Trump administration’s claim about Tylenol is “not backed by the full body of scientific evidence and dangerously simplifies the many and complex causes of neurologic challenges in children.”

“In more than two decades of research on the use of acetaminophen in pregnancy, not a single reputable study has successfully concluded that the use of acetaminophen in any trimester of pregnancy causes neurodevelopmental disorders in children,” Fleischman wrote. “In fact, the two highest-quality studies on this subject—one of which was published in JAMA last year—found no significant associations between use of acetaminophen during pregnancy and children’s risk of autism, ADHD, or intellectual disability.”

ACOG writes on its website that women who experience headaches during pregnancy can use over-the-counter medications like Advil, also called ibuprofen, and Aleve, also known as naproxen, “for migraines that don’t get better with acetaminophen, but only in the second trimester and only for 48 hours or less at a time. It’s not clear if NSAIDs are safe for a fetus during the first trimester. Taking NSAIDs during the third trimester may lead to birth defects.”

Oz wants state Medicaid programs to cover prescriptions

At the press conference, FDA Commissioner Dr. Marty Makary said leucovorin could possibly help alleviate low folate levels, which may be one potential factor in autism. 

“Autism may also be due to an autoimmune reaction to a folate receptor on the brain not allowing that important vitamin to get into the brain cells,” Makary said. “We have a duty to let doctors and the public know we are going to change the label to make it available. Hundreds of thousands of kids, in my opinion, will benefit.”

Administrator of the Centers for Medicare and Medicaid Services Dr. Mehmet Oz said the agency will try to ensure anyone on a government health program can have a prescription for leucovorin covered. 

“Over half of American children are covered by Medicaid and CHIP,” Oz said. “Upon this label change, state Medicaid programs in partnership with CMS will cover prescription leucovorin around the country. It’s yours, but you have to go to a doctor to get a prescription, because they know your child, they know you and they know the medication.”

Oz said he believed that “private insurance companies will rapidly follow our lead if they have not already done so.”

CMS, he said, is also contacting state governments to aid the Trump administration in studying the use of leucovorin as a possible treatment for autism. 

“Collecting real-world data, which is what many of you have been asking us to do in the community, is fast, it is life-saving and we’ll get answers based on what happens over the next few months with this approach,” Oz said. 

NIH research projects picked

Director of the National Institutes of Health Jay Bhattacharya said his agency has selected 13 projects to receive a share of $50 million to look for autism’s root causes and therapies. 

“The studies feature a new kind of science called exposomics, where scientists consider environmental and medical factors, nutrition, events during pregnancy in combination with biology and genetics to answer vital questions about autism,” Bhattacharya said.

Bhattacharya also gave a brief description of autism spectrum disorder, noting it “encompasses a very wide range of symptoms, ranging from mild difficulties in social interactions to profoundly autistic children who experience severe disabilities in speech and behavior.

“Given this wide range of symptoms across the spectrum, it seems certain that there will be a wide range of biological contributors to explaining the cause.”

‘Findings are not entirely consistent’

The Autism Science Foundation wrote in a statement released earlier this month that “low maternal folate levels during early pregnancy have been linked in several studies to an increased risk of autism in children, though findings are not entirely consistent.”

“Data suggesting that leucovorin may be effective come from four small randomized controlled trials, all using different doses and different outcomes, and in one case, reliant on a specific genetic variant,” the Autism Science Foundation notes. “This science is still in very early stages, and more studies are necessary before a definitive conclusion can be reached.”

As for Tylenol, the Society for Maternal-Fetal Medicine released a statement earlier this month that it “continues to advise physicians and patients that acetaminophen is an appropriate medication to treat pain and fever during pregnancy.”

“At this time, the weight of scientific evidence that acetaminophen use during pregnancy causes an increased risk for autism or ADHD is simply inconclusive,” SMFM President Sindhu K. Srinivas wrote in the statement. “In maternal-fetal medicine, as in all of medicine, our recommendations are based on an evaluation of rigorous research and data, clinical expertise, and our patients’ values and preferences.” 

The statement goes on to say that “untreated fever and pain during pregnancy carry significant maternal and infant health risks. Untreated fever, particularly in the first trimester, increases the risk of miscarriage, birth defects, and premature birth, and untreated pain can lead to maternal depression, anxiety, and high blood pressure.” 

Former Chief Medical Officer at the Centers for Disease Control and Prevention Dr. Debra Houry, who resigned from the agency earlier this year, said on a call with reporters before the announcement that she was concerned the conclusions will be premature and not based on solid science. 

“As of three weeks ago, we hadn’t seen evidence that acetaminophen was linked with autism, so it’s curious to know how quickly that was developed,” Houry said. 

Tylenol has information on its website rebutting the assertion that its product has been conclusively linked as a contributor to autism diagnoses. 

“Credible, independent scientific data continues to show no proven link between taking acetaminophen and autism,” its website states. 

The company adds that the best advice is for people to talk “to your healthcare professional before taking or administering acetaminophen.”