In a September 2025 White House briefing, U.S. Secretary of Health and Human Services Robert F. Kennedy Jr. P’07 P’20 claimed that the use of Tylenol by pregnant women was linked to autism. In the same briefing, Food and Drug Administration Commissioner Martin Makary promoted leucovorin — a prescription drug used for cancer-related conditions — as a potential therapeutic for autism.
Earlier this month, a Brown-affiliated study published found that acetaminophen orders for pregnant women during emergency room visits declined and outpatient prescriptions for leucovorin skyrocketed following the September briefing — suggesting the changes in the clinical decision making may be related to the federal statement.
The researchers found that from September to December 2025, acetaminophen orders decreased by 10% among pregnant emergency department patients, while leucovorin prescriptions for children from five to 17 years of age increased by 71%.
“I hope (the study) raises awareness,” said Professor of Health Services, Policy and Practice and co-author Michael Barnett. “People really do listen to federal health officials when they make clear messages, regardless of whether that message is based on evidence or some other motivation.”
In the September briefing, Makary said “a growing body of evidence suggests that some children suffering from autism are folate deficient within the brain — a problem that can be treated with leucovorin,” encouraging physicians to make leucovorin available to “candidate children.”
But leucovorin has not been officially approved for use treating autism. On March 10, the FDA expanded the use of leucovorin for cerebral folate deficiency, a rare genetic condition.
“There is no evidence that cerebral folate deficiency is a common biological presentation” of autism, Associate Professor of Molecular Biology, Cell Biology and Biochemistry Sofia Lizarraga, who studies autism and was not involved with the study, wrote in an email to The Herald.
Autism is a spectrum, according to Lizarraga. She added that autism’s core features include “difficulties in social interactions and communication, repetitive behaviors (and) increased sensory sensitivities.”
Cerebral folate deficiency presents symptoms that are “somewhat overlapping with autism,” said Jeremy Faust, one of the paper’s authors and an assistant professor of emergency medicine at Harvard Medical School. “But it is just a completely different medical condition.”
Barnett believes that many clinicians may be prescribing leucovorin simply because they are being asked to.
“I think honestly it is a bit of a failure of the medical system that it’s so easy for (clinicians) to just prescribe something because it’s just part of the zeitgeist that week,” Barnett said, adding that “more rigorous standards” for incorporating medical information into prescribing habits are needed.
No drugs are currently known to “treat” the “core features” of autism, according to Lizarraga. Claims that leucovorin may be a treatment for autism and that paracetamol use during pregnancy can cause autism lack sufficient evidence, she added.
Faust noted that “acetaminophen is the safest fever-reducing medication during pregnancy,” adding that the drug is “very important in the emergency department.” Acetaminophen is the only over-the-counter medication that has been approved to treat fever in pregnant women.
According to Barnett, there is “suggestive evidence that undertreated fever during pregnancy can be harmful for a fetus.”
“Uncertainty and fear can lead to hesitation around something as familiar and common as Tylenol,” Barnett said.
“The words of our health care leaders in government are powerful,” Faust said. “When we say things prematurely, it ultimately is a huge gamble, and that gamble is with the trust of the public,” he added.
The White House and the FDA did not respond to The Herald’s requests for comment.
Ranjana “Jaanu” Ramesh is a Bruno Brief-er, photographer and Senior Staff Writer covering science & research. She loves service, empathetic medicine and working with kids. When not writing or studying comp neuro, Jaanu is outside, reading, skiing, or observing Providence wildlife (ie: squirrels).
