President Donald Trump’s statements in September about Tylenol use during pregnancy and autism have likely had a real-world impact despite experts and years of evidence disproving any link, according to a new study.
After a Sept. 22 White House briefing, in which Trump, Secretary of Health and Human Services Robert F. Kennedy Jr. and other officials said they had found an “answer to autism” and told pregnant women to avoid taking Tylenol (the brand name for acetaminophen or paracetamol), emergency room orders for the drug took a noticeable downturn, according to research published March 5 in the medical journal The Lancet.
The study found that the use of acetaminophen to treat pregnant patients decreased by 10% in the months that followed the briefing, which attributed an increased risk of autism to Tylenol use during pregnancy, with limited evidence. There was no change in usage, however, for women of the same age who were not pregnant.
This noticeable downward trend in Tylenol orders began as quickly as the day after the conference, according to study co-author Dr. Michael Barnett, professor of health services, policy and practice at the Brown University School of Public Health.
“The rapidity of the response was surprising to us,” he told USA TODAY. “Public officials’ words have power, and both the public and their clinicians shifted behavior immediately.”
‘We’ve regressed so horribly’: Autism groups respond to Trump administration’s Tylenol claims
Fewer Tylenol orders, more prescriptions for unproven treatment: study
The study authors used 2025 U.S. data from an electronic database that housed health records for 294 million patients from over 1,633 hospitals and 37,000 clinics to compare emergency room prescriptions from a period before the White House press briefing (June 30 to Sept. 21) to after (Sept. 22 to Dec. 7).
They found not only that acetaminophen prescriptions for pregnant women aged 15-44 decreased by 10% over the full September to December study period, but also that the decrease peaked at 20% in the third week after Trump’s statements.
Prescriptions trended back toward a more standard number as the study went on, something the authors attribute to the press conference fading from people’s minds and disapproving messages from organizations like the World Health Organization, the American Academy of Pediatrics and the Autistic Self Advocacy Network.
“Because acetaminophen is so familiar and known as safe, there could have been a decay in concern as people went back to normal routines,” Barnett said. “We will need more data to see if there was a durable decrease in use or not over a longer period.”
Tylenol orders for pregnant women at ERs decreased noticeably a September White House briefing.
The study could not account for seasonality (cold and flu season, which begins in November, usually accounts for an increase in acetaminophen prescriptions), pregnant women using acetaminophen at home or treatment outside of emergency departments. Patients and healthcare providers were not interviewed, so it is not known if more patients refused acetaminophen or fewer providers prescribed it in the first place.
The results “show the apparent power that public authority figures have to drive sudden changes in health-care practices,” according to the study. “Here, no new data were presented, and yet immediate use changes were observed.”
At the same press conference, Trump and his advisers also discussed a potential treatment for autism, the drug leucovorin, which Kennedy is reportedly fast-tracking for FDA approval. New outpatient leucovorin prescriptions for children aged 5–17 years increased by 71% during the study period, despite a lack of clinical trials or evidence supporting its use in autistic people.
The Trump administration, Tylenol and autism
The Trump administration has made repeated claims about its plans to find the “cause” for autism. Decades of medical and scientific consensus, however, indicate that there is no singular source, including medication, that can be attributed to autism, which is likely the result of multiple contributing factors like genetics.
U.S. President Donald Trump, next to U.S. Secretary of Health and Human Services Robert F. Kennedy Jr., makes an announcement linking autism to childhood vaccines and to the use of popular pain medication Tylenol for pregnant women and children, claims which are not backed by decades of science, at the White House, in Washington, D.C., U.S., September 22, 2025.
At the September press conference, Trump repeatedly told pregnant women to avoid taking Tylenol unless they can’t “tough it out,” in which case their intake should be limited.
“At this point, there is no definitive evidence of a causal link between prenatal acetaminophen/paracetamol exposure and autism,” Dr. Sara Rodrigues, executive director of Balanced Learning Center, a nonprofit serving autistic and neurodivergent people, told USA TODAY. “The strongest recent synthesis of the literature found no evidence that maternal paracetamol use in pregnancy increases the risk of autism, ADHD, or intellectual disability.”
Even so, she said, fear and alarmist messaging like that coming from the White House tend to strike a nerve and proliferate, strong evidence or otherwise. These trends can have a very real impact, she added.
Physically, the most immediate risk is pregnant people not being treated for conditions like pain or fever, which can be detrimental to health, because they are afraid of the typical first-line option. Socially, she said, it can promote “more guilt, more confusion, more distrust of physicians and public health agencies, and more interest in unproven interventions.”
This article originally appeared on USA TODAY: Pregnant ER patients’ Tylenol usage fell after Trump’s autism claims: study
