KEY POINTS:

• The FDA initiated a label change process for acetaminophen on September 22, 2025, according to the agency’s press announcement
• The White House stated that evidence suggests a link between prenatal acetaminophen use and neurodevelopmental disorders, per its official release
• Major medical organizations including ACOG and SMFM maintain that acetaminophen remains safe for pregnancy use, according to their public statements
• A 2024 Swedish study of 2.5 million children found no association when using sibling controls, as reported in JAMA
• Harvard researchers found evidence of association using Navigation Guide methodology, per their August 2025 BMC Environmental Health study

FDA Takes Action on Acetaminophen Labeling

The U.S. Food and Drug Administration announced on September 22, 2025, that it initiated the process for a label change for acetaminophen products to reflect evidence suggesting potential associations with neurodevelopmental conditions when used during pregnancy, according to the FDA’s press announcement.

FDA Commissioner Marty Makary stated in the agency’s release that “The FDA is taking action to make parents and doctors aware of a considerable body of evidence about potential risks associated with acetaminophen.” The FDA also issued a letter alerting physicians nationwide about the evidence, per the agency’s announcement.

Administration Cites Studies Showing Associations

The White House issued a statement on September 22, 2025, citing multiple large-scale cohort studies that report associations between prenatal acetaminophen exposure and later diagnoses of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). According to the White House release, Press Secretary Karoline Leavitt stated that “There is mounting evidence finding a connection between acetaminophen use during pregnancy and autism.”

The administration’s announcement referenced the Nurses’ Health Study II and the Boston Birth Cohort as finding associations between in utero exposure and neurodevelopmental disorders, according to the White House statement.

Harvard Study Applies Rigorous Methodology

Researchers at Harvard T.H. Chan School of Public Health and Mount Sinai published a systematic review in BMC Environmental Health on August 14, 2025, examining 46 studies on prenatal acetaminophen exposure. According to the published study, the researchers applied the Navigation Guide methodology to evaluate the evidence.

Dean Andrea Baccarelli of Harvard T.H. Chan School of Public Health, who was senior author, stated in the Harvard news release that his team “found evidence of an association between exposure to acetaminophen during pregnancy and increased incidence of neurodevelopmental disorders in children.” The Mount Sinai announcement reported that the study found higher-quality research was more likely to show positive associations.

Swedish Study Challenges Association

A large Swedish cohort study published in JAMA on April 9, 2024, examined 2.5 million children and found different results when using sibling controls. According to the JAMA publication, while models without sibling controls showed marginally increased risks, analyses of matched full sibling pairs found no evidence of increased risk.

The JAMA study reported hazard ratios of 0.98 for both autism and ADHD when using sibling control analysis, suggesting that associations observed in other models may have been attributable to familial confounding, per the published research.

Medical Organizations Push Back

The American College of Obstetricians and Gynecologists (ACOG) issued a practice advisory on September 23, 2025, reaffirming that acetaminophen remains the analgesic and antipyretic of choice during pregnancy. ACOG stated in its advisory that “the current weight of evidence does not support a causal link between prenatal acetaminophen use and neurodevelopmental disorders.”

The Society for Maternal-Fetal Medicine (SMFM) released a statement on September 22, 2025, advising that acetaminophen is an appropriate medication to treat pain and fever during pregnancy. SMFM President Sindhu K. Srinivas stated in the organization’s release that “the weight of scientific evidence that acetaminophen use during pregnancy causes an increased risk for autism or ADHD is simply inconclusive.”

Important Context About Risk Assessment

The FDA noted in its announcement that while an association has been described in many studies, a causal relationship has not been established and there are contrary studies in the scientific literature. The agency emphasized that acetaminophen is the only over-the-counter drug approved for treating fevers during pregnancy, per the FDA statement.

According to the FDA’s announcement, high fevers in pregnant women can pose risks to children, and alternatives like aspirin and ibuprofen have well-documented adverse impacts on the fetus. The agency stated that the choice remains with parents and that it remains reasonable for pregnant women to use acetaminophen in certain scenarios.

Company Disputes Characterization

Kenvue, the manufacturer of Tylenol, issued a response challenging the proposed label changes. According to CNN’s October 20, 2025 report, the company stated that acetaminophen is “one of the most studied medicines in history” and called the proposed labeling revisions “arbitrary, capricious, and contrary to law.”

CNN reported that Kenvue met with HHS Secretary Kennedy in early September and told him there was no link between acetaminophen use during pregnancy and autism.

Research Limitations and Ongoing Debate

Johns Hopkins researchers who conducted earlier studies noted important caveats. According to a November 5, 2019 article in the Johns Hopkins Hub, researcher Xiaobin Wang cautioned that although their study found associations, “it should not be interpreted that the Tylenol use causes these disorders.”

The Harvard study published in BMC Environmental Health acknowledged that sibling-controlled studies have shown null results but attributed this to methodological challenges including exposure misclassification and reduced statistical power, according to the published research.

Clinical Guidance Remains Divided

Medical professionals emphasize the need for individualized care decisions. UT Southwestern Medical Center issued guidance on September 26, 2025, advising patients to continue following their physician’s direction and noting that acetaminophen remains the analgesic and antipyretic of choice during pregnancy, per their published statement.

The Washington State Nurses Association issued a statement on September 24, 2025, supporting continued acetaminophen use and stating that “the overwhelming body of evidence confirms that acetaminophen is safe and appropriate for the management of pain or fever in pregnancy,” according to their release.