Washington D.C. – Former President Donald Trump's recent assertions linking acetaminophen, commonly known as Tylenol, to an increased risk of autism have ignited a fierce debate within the scientific and medical communities. Trump, alongside Health and Human Services (HHS) Secretary Robert F. Kennedy Jr., announced in September 2025 that the Food and Drug Administration (FDA) would begin notifying physicians about a potential association between prenatal acetaminophen use and autism, urging pregnant women to "fight like hell not to take it." This directive, however, stands in stark contrast to the prevailing scientific consensus and has been met with significant criticism from leading medical organizations worldwide.
The Genesis of a Controversial Claim
During a September 2025 press conference, President Trump stated that the FDA believed acetaminophen use during pregnancy could be associated with a "very increased risk of autism." He explicitly advised pregnant women against taking Tylenol unless "medically necessary," and ideally, "a woman won't take Tylenol." This announcement was framed as a major step in understanding the "root causes of autism," which the administration described as an "epidemic." HHS Secretary Kennedy Jr. supported the claim, citing "clinical and laboratory studies" that suggest a potential association between acetaminophen used during pregnancy and adverse neurodevelopmental outcomes. The White House later released a statement citing studies that reported associations between in utero exposure and diagnoses of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), and mentioned proposed biological mechanisms.
Nuance in the Science: Association vs. Causation
The scientific landscape regarding acetaminophen and neurodevelopmental disorders is complex. Several large observational studies have reported "associations" between frequent or prolonged acetaminophen use during pregnancy and higher rates of neurodevelopmental disorders in children. One recent systematic review, led by researchers at Mount Sinai, analyzed 46 previous studies and concluded that the evidence supported an association between prenatal acetaminophen exposure and increased incidence of neurodevelopmental disorders. The review's senior author, Andrea Baccarelli, MD, PhD, stated that this association was strongest when acetaminophen was taken for four weeks or longer. Some studies suggest acetaminophen may trigger oxidative stress, disrupt hormones, and cause epigenetic changes that interfere with fetal brain development.
However, medical experts, including Yale School of Public Health Associate Professor Dr. Zeyan Liew, emphasize that "association" does not equate to "causation." Many of these studies are observational, meaning they can identify correlations but cannot definitively prove that acetaminophen directly causes autism. Confounding factors, such as the underlying reasons a pregnant person takes acetaminophen (e.g., fever, infection, severe pain), could be the actual drivers of any observed associations. Fevers, maternal inflammation, and immune system activation during pregnancy are known to pose risks to the developing fetus and have been independently linked to an increased risk for autism.
Overwhelming Scientific Consensus: No Causal Link
Despite the recent administration's warning, a broad consensus among leading medical organizations and scientists maintains that no causal link between acetaminophen use during pregnancy and autism has been established. Organizations like the American College of Obstetricians and Gynecologists (ACOG), the Society for Maternal-Fetal Medicine, the American Academy of Pediatrics (AAP), Health Canada, and the World Health Organization (WHO) have all reaffirmed that acetaminophen remains the safest over-the-counter pain reliever and fever reducer recommended for pregnant women when used as directed.
A major study published in 2024, involving nearly 2.5 million children in Sweden over 25 years, found that while an initial slight association between prenatal acetaminophen exposure and neurodevelopmental disorders was observed, this risk disappeared when comparing siblings. Sibling studies are considered more robust as they control for shared genetic and environmental factors, suggesting that previous associations might have been influenced by other variables, such as parents with neurodevelopmental disorders being more likely to use acetaminophen.
The FDA itself, in an open letter issued after Trump's announcement, acknowledged that "while an association between acetaminophen and autism has been described in many studies, a causal relationship has not been established and there are contrary studies in the scientific literature." The agency stressed that acetaminophen is still considered the safest over-the-counter alternative for pain and fever during pregnancy, and emphasized the risks of untreated fever, which can lead to neural tube defects and preterm birth.
Public Health Implications and Expert Reactions
The statements by the Trump administration have drawn strong condemnation from the medical community, with many experts calling them "irresponsible," "dangerous," and "anti-science." The Autism Science Foundation stated that "any association between acetaminophen and autism is based on limited, conflicting, and inconsistent science and is premature." They, along with other organizations, expressed concern that such claims could mislead families and undermine public trust in established medical guidance.
The core message from healthcare providers is clear: untreated pain and fever during pregnancy can pose significant risks to both the mother and the developing fetus. Conditions like high fever can increase the risk of neural tube defects and preterm birth. Therefore, medical professionals advise pregnant women to continue using acetaminophen at the lowest effective dose for the shortest duration necessary, under medical guidance, to manage these conditions.
Conclusion
The debate surrounding acetaminophen use during pregnancy and its potential link to autism highlights the critical distinction between scientific association and causation. While some studies have identified correlations, the overwhelming body of evidence, including large-scale and sibling-controlled research, does not support a causal relationship. Medical and scientific organizations globally continue to recommend acetaminophen as the preferred and safest over-the-counter option for managing pain and fever during pregnancy. Public health guidance remains centered on evidence-based medicine, urging pregnant individuals to consult their healthcare providers for medical advice rather than relying on unsubstantiated claims, ensuring they receive necessary and safe treatment for their health and that of their unborn children.
