Key points of Trump's announcement linking paracetamol to autism: "The risk is not treating the fever."

Donald Trump, accompanied by U.S. Secretary of Health and Human Services Robert F. Kennedy Jr., announced yesterday from the White House that the use of paracetamol during pregnancy could be linked to an increased risk of children developing autism spectrum disorders (ASD) .

This news had already been reported by American media outlets such as The Washington Post and The Wall Street Journal, among others, as well as by President Donald Trump himself at an event organized this past Saturday by the conservative think tank American Cornerstone Institute: "On Monday, we'll be making an announcement about autism," he said. "I think it will be a very important announcement. I think it will be one of the most important things we do."

Specifically, Trump stated that "the FDA [Food and Drug Administration] will be notifying physicians that the use of acetaminophen [paracetamol], commonly known as Tylenol [the US brand name], during pregnancy may be associated with a greatly increased risk of autism. So taking Tylenol is not good. I'll say it: it's not good."

"Don't take it. Don't take it," the tycoon insisted. "Sadly, the first question is: What can you take instead? Well, in fact, there isn't an alternative. Other medicines have been definitively proven to be bad , like aspirin or Advil [a brand name for ibuprofen]."

Autism in the spotlight

This new move by the United States government comes at a time when autism diagnoses have been growing significantly for over two decades. The issue has been attracting institutional attention for some time, and Kennedy recently declared that the country is in the midst of an "autism epidemic" fueled by "environmental toxins."

The data, however, may be misleading. Several experts (such as researcher Christine Ladd-Acosta of the Wendy Klag Center for Autism and Developmental Disabilities, in an article for the prestigious Johns Hopkins University ) have warned that, as worrying as the trend may seem, most of the increase in detected cases is explained more by a broadening of the definition of autism and an improvement in detection than by an actual increase in the prevalence of the condition.

In fact, Dr. James McPartland, director of the Yale Center for Brain and Mental Health, explained to CNN that "when we look at changes in diagnostic trends over time, [cases of severe autism, in which the patient lacks verbal skills] are the sector that has remained most stable. It is people with greater cognitive and verbal ability who have been included more in the spectrum in recent years."

It should also be noted that autism spectrum disorders (ASD) have been the focus of many pseudoscientific and conspiracy theories for decades. For example, anti-vaccine movements often claim that it is a consequence of immunization against various infections (and, in particular, of the MMR vaccine).

The problem is that ASDs are very complex conditions , and the exact cause of them is unknown. In fact, scientists are inclined to believe that rather than a single cause, many factors contribute to the risk of the disease, including factors such as genetics or certain developmental events in children.

McPartland underscores this point: "The most important thing that was said at [Trump's] conference is that autism is complex , with a multifactorial etiology. That's true. What it means is that autism is complicated, and it doesn't have one cause, which is Tylenol, and it doesn't have one cause, which is folate. It's extremely complicated."

Of course, the evidence for a possible cause of the disease in exposure to environmental toxins or drugs is tenuous, to say the least, and the hypothesis that it is caused by vaccines has no scientific validity.

Weak evidence

The theory that paracetamol use during pregnancy could be linked to an increased risk of children developing autism seems to be supported by a couple of recent studies (such as one published in the academic journal J AMA Network in 2024 or one published in August of this year in Environmental Health ) that have found some statistical association (but not causal links) between the two phenomena. However, these findings need to be qualified.

The first is a nationwide study conducted in Sweden that included a population sample of nearly two and a half million children born between 1995 and 2019, and which constitutes the largest study on the subject to date. Furthermore, the research method included a sibling control analysis, an experimental design in which a person with the condition is compared with an unaffected sibling to control for potential factors that could affect risk.

Thus, the study found in models without sibling control analyses that children whose mothers had used paracetamol did have a very marginally increased risk of ASD or attention-deficit/hyperactivity disorder (ADHD). However, this association was not present in the sibling control analyses, which, as the authors emphasize, actually suggests that this slight increased risk is due to other factors.

In the second study, the authors analyzed data from 46 previous studies on the subject. They concluded that a significant proportion of these studies, including some of the highest-quality experimental studies, had found a relationship (albeit modest) between the risk of autism and paracetamol use during pregnancy.

However, they also noted that another significant portion had ruled out the influence or even presented evidence of a possible protective effect. Finally, the signatories themselves emphasize that this type of analysis does not validate causal mechanisms.

The possibility of 'publication bias' should also be kept in mind: scientific circles tend to avoid publishing research that doesn't show significant associations, which ends up influencing the results of literature reviews like this one.

Ultimately, the association between paracetamol and autism is based on limited, contradictory and inconsistent evidence , and, according to the Autism Science Foundation , "is premature for the current state of the art."

Paracetamol, the safest option

Even so, we might think that even though the scientific evidence is somewhat limited, it would be advisable to recommend opting for other alternatives and avoiding the use of paracetamol during pregnancy. But, again, it's not that simple.

The real change taking place now is that the FDA, the regulatory body in the United States, is now recommending avoiding acetaminophen except in cases of high fever in pregnant women during the first trimester. This new position doesn't substantially change current practice (which generally recommends avoiding the drug as much as possible during pregnancy), but experts are concerned about the message the White House is sending to the general public.

James McPartland explained in the CNN interview that "practically speaking, the recommendation isn't much different than what was previously recommended. Until now, the suggestion was to use Tylenol and any other medication during pregnancy as little as possible, so what was discussed today is in line with what has been done for a long time. Pregnant women should consult with their obstetricians about what is appropriate for them, taking into account the risk factors associated with the disease during pregnancy."

There are reasons why clinical guidelines have recommended the use of acetaminophen during pregnancy for the treatment of fever and pain. First, because, as the FDA itself notes, other common alternatives such as nonsteroidal anti-inflammatory drugs (for example, ibuprofen or naproxen) have been shown to pose significant risks to the fetus, especially beyond the twentieth week of gestation.

Second, ignoring conditions like fever or pain during pregnancy is far more dangerous than theoretical concerns about acetaminophen use based on inconclusive evidence. The U.S. Centers for Disease Control (CDC), for example, has repeatedly warned that fever during pregnancy can lead to complications and birth defects. The Society for Maternal-Fetal Medicine has also warned that untreated pain and fever during pregnancy carry significant risks for both mother and child. McPartland corroborates this point: "The risk is not treating a fever in a pregnant woman."

For all these reasons, leading authorities on the subject continue to recommend treating fever and pain during pregnancy with paracetamol, in light of the current state of the situation. Any alternative currently carries more proven risks, so, regardless of alarmist and sensationalist statements from an administration that has often demonstrated a poor respect for scientific rigor, prudence demands being guided by the available evidence and listening to the recommendations of experts.

References

Dan Diamond & Ariana Eunjung. Trump administration set to tie Tylenol to autism risk, officials say. The Washington Post (2025). Accessed online at https://www.washingtonpost.com/health/2025/09/21/trump-autism-announcement-tylenol-leucovorin/ on September 22, 2025.

Liz Essley Whyte, Nidhi Subbaraman. RFK Jr., HHS to Link Autism to Tylenol Use in Pregnancy and Folate Deficiencies. The Wall Street Journal (2025). Accessed online at https://www.wsj.com/health/healthcare/rfk-jr-hhs-to-link-autism-to-tylenol-use-in-pregnancy-and-folate-deficiencies-e3acbb4c on September 22, 2025.

Public Health On Call. Is There an Autism Epidemic? John Hopkins Bloombrg School of Public Health (2025). Accessed online at https://publichealth.jhu.edu/2025/is-there-an-autism-epidemic on September 22, 2025.

CNN (2025). Doctor refutes FDA commissioner on Tylenol & autism link. Accessed online at https://edition.cnn.com/2025/09/22/health/video/the-lead-children-autism-doanld-trump-rfk-jr-health-tylenol-acetaminophen on September 23, 2025.

Victor H. Ahlqvist, Hugo Sjöqvist, Christina Dalman et al. Acetaminophen Use During Pregnancy and Children's Risk of Autism, ADHD, and Intellectual Disability. JAMA Network (2025). DOI: 10.1001/jama.2024.3172

Diddier Prada, Beatee Ritz, Ann Z. Bauer & Andrea A. Baccarelli. Evaluation of the evidence on acetaminophen use and neurodevelopmental disorders using the Navigation Guide methodology. Environmental Health (2024). DOI: https://doi.org/10.1186/s12940-025-01208-0

Autism Science Foundation (2025). Statement from Autism Science Foundation Regarding Wall Street Journal Report “RFK Jr., HHS to Link Autism to Tylenol Use in Pregnancy and Folate Deficiencies.” Viewed online at https://autismsciencefoundation.org/press_releases/statement-from-autism-science-foundation-regarding-wall-street-journal-report-rfk-jr-hhs-to-link-autism-to-tylenol-use-in-pregnancy-and-folate-deficiencies/ on September 22, 2025.

FDA (2023). FDA recommends avoiding use of NSAIDs in pregnancy at 20 weeks or later because they can result in low amniotic fluid. Viewed online at https://www.fda.gov/drugs/drug-safety-and-availability/fda-recommends-avoiding-use-nsaids-pregnancy-20-weeks-or-later-because-they-can-result-low-amniotic on September 22, 2025.

CDC (2024). Heat & Pregnancy. Accessed online at https://www.cdc.gov/heat-health/risk-factors/heat-and-pregnancy.html on September 22, 2025.

Society for Maternal-Fetal Medicine (2025). SMFM Statement on Acetaminophen Use During Pregnancy and Autism. Accessed online at https://www.smfm.org/news/smfm-statement-on-acetaminophen-use-during-pregnancy-and-autism- on September 22, 2025.

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