A September 2025 White House briefing in which women expressed concerns about acetaminophen use during pregnancy and touted the drug leucovorin as a potential autism treatment led to a radical change in how doctors across the country prescribe these drugs, according to a new study.
The study shows that after the September 22, 2025 briefing, orders for acetaminophen for pregnant women in the emergency room decreased significantly, while prescriptions for leucovorin for children increased dramatically.
The study was authored by researchers from the Brown University School of Public Health and Brigham General, Massachusetts. Lancet.
According to the authors, the changes in the use of both drugs are notable because they are specific to the drugs mentioned in the publication and occurred despite the absence of new clinical trial data or formal guideline revisions during that time period.
An important implication of these results is that patients are not the only ones affected by unconventional press conferences. These doctors were either influenced themselves or inspired by their patients to adopt new practices. ”
Dr. Michael Barnett, study author, physician, and professor of health services, policy, and practice at Brown University
The findings are based on data from Cosmos, a large electronic medical records database that includes information from more than 1,600 hospitals and 37,000 clinics across the United States. The researchers analyzed weekly prescribing trends before and after the information session. They compared the observed prescriptions to the expected levels based on previous patterns.
The study notes that during the briefing, government officials claimed that acetaminophen use during pregnancy may be associated with an increased risk of autism. They also suggested that leucovorin, a folic acid-based drug approved for certain cancer-related uses and metabolic conditions, could be used to treat autism. Leucovorin is being studied in small clinical trials for autism with preliminary results, but it is not included in standard autism treatment guidelines.
After a briefing that included comments from the president and the head of the Food and Drug Administration, acetaminophen use among pregnant women treated in emergency rooms decreased by about 10% compared to what researchers expected based on previous trends. The decline in the first month was 16%, and in the third week the lowest value was 20% below the expected level.
At the same time, outpatient prescriptions for leucovorin increased significantly among children aged 5 to 17 years. Overall, leucovorin prescriptions were approximately 71% above expected levels after the information session. In the first month, they increased by 93%. In the second week, the number of prescriptions more than doubled compared to what researchers expected.
Of note, approximately 72% of leucovorin prescriptions were written for children diagnosed with autism, and this group represents only 4% of the pediatric population in our dataset.
The authors say the findings highlight the broader impact of public health communication and show how high-profile federal messages can influence clinical decision-making across the country.
“The White House briefing was a highly unusual mechanism for communicating medical information that bypassed many standard checks to ensure accurate messaging,” Burnett said. “This result shows how much political leaders can induce health behaviors even when the evidence for these treatments remains unchanged.”
Because of the study design, the authors note that this analysis does not prove that the White House briefings caused prescription changes, nor does it assess whether patients experienced better or worse outcomes as a result. Still, the observed association is significant, they said.
“The results were surprising to me,” said study author Dr. Jeremy Samuel Faust, an emergency physician at Brigham and Women’s Hospital and an assistant professor at Harvard Medical School. “It can take years or even decades for high-quality research to finally reach clinicians. Here, by using the White House, it happened overnight. Unfortunately, they are claiming breakthroughs that simply haven’t materialized.”
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Reference magazines:
Faust, J. S., and Barnett, M. L. (2026). Changes in paracetamol and leucovorin usage after the White House press conference. Lancet. DOI: 10.1016/S0140-6736(26)00243-6. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(26)00243-6/fulltext.
