U.S. Health and Human Services Secretary Robert F. Kennedy Jr., looks on as he attends to testify before a Senate Finance Committee hearing on President Donald Trump's 2026 health care agenda, on Capitol Hill in Washington, D.C., U.S., September 4, 2025. REUTERS/Jonathan Ernst

By Michael Erman and Julie Steenhuysen

(Reuters) -U.S. Health Secretary Robert F. Kennedy Jr. plans to announce that use of Kenvue's popular over-the-counter pain medication Tylenol in pregnant women is potentially linked to autism, The Wall Street Journal reported on Friday, citing people familiar with the matter, without including evidence for the claims.

Kennedy, in the report, will also suggest a medicine derived from folate called folinic acid can be used to treat symptoms of autism in some people, the WSJ reported.

Shares of Kenvue fell 14% after the report. Tylenol, whose active ingredient is acetaminophen, is a widely used pain reliever, including by pregnant women.

Kenvue said in a statement that it believes there is no causal link between Tylenol use during pregnancy and autism. The company advises expecting mothers to speak to healthcare professionals before taking OTC medications, including Tylenol.

The U.S. Food and Drug Administration and leading medical organizations agree on the safety of acetaminophen, its use during pregnancy, and the information provided on the label, the company said.

Kennedy has promised to find the cause of autism and has long suggested it is related to vaccines without scientific proof. He has also said it must be related to an "environmental toxin." Decades of science have yet to establish a definitive cause.

Under Kennedy, the National Institutes of Health is running an Autism Data Science Initiative that aims to mine large datasets to investigate possible contributors to autism and evaluate the outcomes of existing treatments. Researchers have submitted more than 100 proposals to participate in the $50 million study, with a list of up to 25 grant winners expected to be announced by the end of September, people with knowledge of the plans told Reuters.

The WSJ said that a report is likely to highlight how low levels of folate, an important vitamin, and Tylenol taken during pregnancy, could be a potential cause of autism.

"What's striking to me is that this report is supposed to uncover all these new causes, and so far, all we're learning is that they're rehashing existing research," said Dr. David Mandell, a professor of psychiatry and autism expert at the University of Pennsylvania.

"We have no understanding of why there might be a biological reason that Tylenol would cause autism."

In December 2023, a U.S. federal judge struck a blow to hundreds of lawsuits claiming Tylenol can cause autism if mothers take it during pregnancy, barring expert witnesses from testifying after finding they lacked scientific evidence for their claims.

Last August, citing that ruling, the judge dismissed all the cases in federal court. A U.S. appeals court is slated to hear arguments next month in an appeal of that ruling, court records show.

"We are using gold-standard science to get to the bottom of America’s unprecedented rise in autism rates. Until we release the final report, any claims about its contents are nothing more than speculation," said an HHS Spokesperson.

ANTI-VACCINE GROUP FORECAST

Children's Health Defense, the anti-vaccine group formerly headed by Kennedy, has posted several times in recent weeks on social media site X about the potential link between Tylenol and autism.

Brian Hooker, chief scientific officer of CHD, said in a recent video posted on X that he expects Kennedy's autism report to hit on Tylenol, but also vaccines and vaccine components.

CHD has cited a study published in August that found evidence of an association between use of acetaminophen by pregnant women and neurodevelopmental disorders such as autism in their offspring.

The scientists recommended medical guidelines advise that pregnant women use the lowest possible dose for the shortest time needed.

They noted that more studies were required to confirm any association and that failure to treat fever in pregnant women could lead to other fetal problems, such as neural tube defects.

Other studies have not found a link. A 2024 study published in the Journal of the American Medical Association involving 2.4 million children born in Sweden found no evidence to support a causal link.

"There is no clear evidence that proves a direct relationship between the prudent use of acetaminophen during pregnancy and fetal developmental issues," said Christopher Zahn, chief of clinical practice for the American College of Obstetricians and Gynecologists.

(Reporting by Michael Erman in New Jersey and Julie Steenhuysen in Chicago, Additional reporting by Puyaan Singh in Bengaluru and Nancy Lapid in Tucson; Editing by Vijay Kishore and Aurora Ellis)