President Donald Trump announced that the FDA will immediately notify physicians about an alleged association between acetaminophen use during pregnancy and increased autism risk, triggering a sharp decline in shares of Tylenol manufacturer Kenvue.
"Effective immediately, the FDA will be notifying physicians that the use of acetaminophen, which is basically commonly known as Tylenol during pregnancy, can be associated with a very increased risk of autism," Trump said at a press conference.
Market Response and Company Position
Kenvue shares fell over 7% on Monday following the announcement, extending a 25% decline over the past six months as investor anxiety has grown around potential autism links. The company, which was spun off from Johnson & Johnson in 2023, strongly rejected the administration's position.
"We believe independent, sound science clearly shows that taking acetaminophen does not cause autism. We strongly disagree with any suggestion otherwise and are deeply concerned with the health risk this poses for expecting mothers," Kenvue stated.
The company emphasized that acetaminophen represents the safest pain relief option for pregnant women, warning that without it, "women face dangerous choices: suffer through conditions like fever that are potentially harmful to both mom and baby or use riskier alternatives."
Scientific Evidence and Expert Analysis
Health and Human Services Secretary Robert F. Kennedy Jr. has previously promoted connections between autism and acetaminophen, as well as vaccines and environmental toxins. In May, Kennedy vowed to identify autism causes by September, a timeline that scientists criticized as unrealistic for comprehensive scientific inquiry.
However, numerous public health experts maintain there is no evidence proving a causal relationship between acetaminophen and autism. A landmark 2024 study comparing siblings who were and were not exposed to Tylenol in utero largely debunked the alleged link, despite earlier studies finding correlations.
Ari Ne'eman, assistant professor of health policy and management at the Harvard T.H. Chan School of Public Health, explained that the urgency to find autism causes is based on a misconception that increased diagnoses equal increased prevalence.
"All of this is predicated on the idea that there's an actual, real increase in not just the diagnosis, but in the actual disability that we call autism," Ne'eman told Fortune. "There's very good reason to believe that that is not the case, that what we are actually seeing is a recognition of a population that's always existed, but previously existed under other names, or in some cases, no name at all."
Though autism diagnoses have increased by 175% during the past decade, this likely reflects better understanding of the condition rather than actual prevalence increases.
Legal Challenges and Market Impact
Kenvue has previously faced hundreds of lawsuits alleging failure to warn about autism and ADHD risks from prenatal acetaminophen exposure. A federal judge dismissed the remaining federal cases in August 2024, citing lack of scientific evidence to support expert testimony.
Despite ongoing legal challenges, BNP Paribas analysts note that Kenvue's acetaminophen sales remained unaffected during previous litigation. Navann Ty, a senior healthcare analyst at BNP Paribas, observed: "Despite the litigation, we haven't seen an impact on Tylenol consumption and market share, and they continue to do well."
However, the current situation differs from previous legal challenges because the Trump administration's announcement brings consumer awareness beyond just the investor community. According to analysts, Tylenol represents an estimated 10% of Kenvue's total revenue within the company's self-care segment.
Ongoing Appeals and Future Implications
Ashley Keller, partner at Keller Postman LLC, will co-lead an appeals case with oral arguments scheduled for next month. Keller maintains that recent scientific evidence supports the acetaminophen-autism connection, citing a 2020 University of Washington study finding associations between acetaminophen exposure in babies' meconium and increased ADHD odds.
"The public health community and government officials who organize the public health at the federal level are paying heed to this analysis and are doing the right thing by ensuring that pregnant women get some sort of warning," Keller said.
The Autism Society of America previously criticized Kennedy's approach as "harmful, misleading and unrealistic," noting that referring to autism as an "epidemic" is "both inaccurate and stigmatizing."
