Trump linked the development of autism to taking paracetamol. Where did this statement come from and what do scientists think about it?

September 22 US President Donald Trump spoke at a press conference alongside his longtime health minister enemy vaccinations by Robert Kennedy Jr. The American leader recalled how many years ago he discussed with him the problem of autism spectrum disorders (ASD), which are increasingly being diagnosed in children. “It's something artificial. They are taking something,” Trump said. He then named the main “suspect” - it turned out to be paracetamol. The US President announced that soon all American doctors will be notified of the proven connection between taking this “harmful” drug during pregnancy and the development of autism in the child. 

“Verified” tells how justified Trump’s statements are and what scientists think about the connection between paracetamol and autism.

To begin with, a few methodological clarifications and limitations. Trump and Kennedy Jr., and after them many Western media use the name “Tylenol” is unusual for the Russian-speaking reader. From the point of view composition Tylenol is identical to paracetamol, another name for this substance is acetaminophen. It can be sold both as an independent medicine and in composition other antipyretics and pain relievers, such as Theraflu, Efferalgan and Panadol.

In the instructions for some of these drugs states that they should be used with caution during pregnancy: “Carefully weigh the expected benefit of therapy for the mother and the potential risk to the fetus.” IN others cases it is indicated: “Paracetamol can be used during pregnancy, but it is advisable to use the minimum effective doses and the shortest possible course” (at the same time, an overdose of paracetamol among pregnant women observed more oftenthan with any other medicine). Moreover, all instructions indicate that if the recommendations are followed, the drug does not have a harmful effect on the fetus.

Paracetamol is considered the only antipyretic and analgesic drug, which, unlike popular analogues, is suitable for pregnant women at any stage of gestation. Thus, the US Food and Drug Administration (FDA) does not recommend take ibuprofen from the 20th week of pregnancy, Russian specialists - in the third trimester (that is, from the 28th week). The same applies to other non-steroidal anti-inflammatory drugs. 

The problem is that in reality, the safety of many drugs has been little studied in pregnant women, and for good reason. The most accurate method of such research, the gold standard of evidence-based medicine, is randomized clinical trials, in which volunteers are divided into two groups: one is given a drug, the other is given a placebo, and then scientists compare their performance. In the case of pregnant women, such studies are extremely difficult to conduct, primarily for ethical reasons. Only 4% of clinical trials conducted over the past decade admitted participation of pregnant women. 

In these conditions, scientists are trying to obtain at least some data through cohort studies. This method assumes that the researchers do not simulate a situation in which some volunteers receive the drug and others receive a “dummy”, but observe those who did or did not take the drug during pregnancy. At the same time, identifying patterns becomes more difficult. Thus, in a situation where women in one group were treated with paracetamol during pregnancy, but not in the other, it is difficult to determine what exactly caused the child’s problems: treatment, an infection suffered by the mother, or a coincidence of both factors. The main advantage of cohort studies is the ability to analyze a larger volume of data. 

Although Trump speaks about the autism epidemic, the idea of ​​the increasing prevalence of this disorder is not entirely corresponds reality. Firstly, in recent years, the standards for diagnosing ASD have expanded significantly - borderline states, which would previously have been considered normal, are now classified as mild or atypical forms of autism. Secondly, in 2013, the United States adopted a new edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). It grouped several diagnoses under the umbrella term “autism spectrum disorder”: autism, Asperger syndrome, childhood disintegrative disorder and pervasive developmental disorder. In many ways, it was the change in nomenclature that led to the fact that children began to be diagnosed with ASD more and more often.

What is Trump's statement based on?

IN article “Evidence Shows Link Between Acetaminophen and Autism” on the White House website provides links to several scientific papers and statements from scientists that support this hypothesis. The most recent of them is published in August study, conducted by specialists from the Mount Sinai Medical Center, as well as Harvard, the University of California and the University of Massachusetts. Other references include a commentary by one of his co-authors and press releases associated with its publication.

The study is a systematic analysis of 46 earlier cohort studies on paracetamol use during pregnancy (a combined sample of more than 100,000 women in different countries). However, only eight of these studies were devoted to the connection between the use of this drug and the occurrence of ASD. Another 20 focused on attention deficit hyperactivity disorder (ADHD), and 18 focused on other neurodevelopmental disorders.

The article makes an ambivalent impression. On the one hand, scientists rightly point out limitations in research on this topic - for example, they draw attention to problems with collecting data on medication use. Thus, answering the question “What drugs did you take [during pregnancy]?”, only 7.5% of women name paracetamol, while in a blood test this figure exceeds 50%. This is probably due to the fact that many patients don't perceive paracetamol as a “real” medicine – it is available without a prescription, often in the form of sweet or sour soluble tablets. The authors of the study also write about the double-whammy theory: women take paracetamol because of an infection, headache or fever, but it is difficult to determine whether the disease or treatment will affect the fetus.

On the other hand, the abstract of the article and its text contradict each other. The abstract states: pregnant women should be informed that paracetamol intake should be limited for the sake of the successful neurodevelopment of their children. Judging by reviews reviewers, statements about a cause-and-effect relationship were contained in the original version of the article, but in the final version the authors became less categorical and pointed only to an association: among children whose mothers took paracetamol during pregnancy, more of those who had similar neurological problems were identified. This conclusion is based on findings from five of the eight case studies reviewed. In two more cases, scientists did not identify any connections, and in one case they could not come to a clear conclusion.

As a result, in the text itself, the study authors do not call for the abandonment of paracetamol during pregnancy, but for its judicious use. By this they mean the use of the minimum effective dose for a minimum time under medical supervision and taking into account the individual characteristics of the body. “Left untreated, pain or fever can also harm the baby. Our study highlights the importance of discussing the safest approach with healthcare professionals and considering non-drug options when possible." it says in a press release about the study on the Mount Sinai website. 

What else is wrong with this study?

Although the research topic lies at the intersection of epidemiology, pharmacology and psychiatry, its authors published an article in a non-core (albeit authoritative) journal Environmental Health (“Environment and Health”). This choice was probably partly due to the terms of one of the two grants that provided funding for the scientists - his received co-author of the work Andrea Baccarelli from Harvard University to study how air pollution affects age-related changes. The second grant also has nothing to do with research on the connection between taking medications during pregnancy and possible consequences for the child - money were allocated in favor of Mount Sinai to hire specialists from underrepresented groups (the main author of the article, Didier Prada, is a native of Colombia).

It is noteworthy that the same Baccarelli earlier was an expert on behalf of the plaintiffs in litigation against the manufacturer of Tylenol. Then a group of parents of children with ASD and ADHD filed a lawsuit against Johnson & Johnson, whose products allegedly caused the disease. The court found no reason to hold the company liable, and assessed the expert’s work as biased: he “selectively analyzed the literature,” “repeatedly insisted on conclusions that the authors of the studies were not ready to make,” and “ignored studies that did not support his opinion.”

What does the scientific community think about the study?

In general, other scientists were skeptical about the article. “[The authors] took data from real studies, but passed off the weakest ones as strong, and considered the most significant ones to be weak. From the data of a small group of studies that studied the connection between paracetamol taken during pregnancy and diseases of the newborn child, they tried to make a collage that seemed to be more convincing than each article separately,” notes geneticist Dmitry Pruss. He emphasizes that the authors of the article analyzed very heterogeneous studies: “questionnaires on motor activity, on psychological activity, questionnaires of nurses who work with the medical diagnoses themselves” - and therefore their conclusion is rather random. 

On the resource PubPeer, where experts evaluate scientific publications, scientists also criticize the research methodology. In particular, one commentator searched scientific citation databases for keywords identified in the article and found numerous papers that its authors had ignored. Another user noted that the researchers said they used a “unique” data collection method called “navigation guidance,” but did not explain what this method was.

In some cases, the paper's authors' conclusions were more vague than those of the colleagues whose studies they analyzed. First of all this Job Swedish scientists under the leadership of Professor Victor Ahlqvist. Experts studied more than 2 million children born from 1995 to 2005. What makes the study particularly interesting is that the researchers recruited pairs of discordant siblings whose mother had taken paracetamol during one pregnancy and not during the second. Swedish scientists have concluded that genetic factors play a more significant role in whether a child develops ASD than the mother's use of certain medications. Similar point of view adhere to and other researchers: although the exact mechanism of occurrence of this disorder has not yet been established, up to 80% of all cases of autism may have a hereditary component. At the same time, the authors of the review cited by the White House did not pay any attention to the genetic component of ASD. 

How do they react to Trump's statements?

In a commentary for The Nature magazine, Ahlquist noted: The belief that there is a link between taking certain medications during pregnancy and the development of autism in the child can negatively affect parents. “We risk placing blame on mothers and causing even more stress, self-blame and stigma, despite the lack of evidence to support such claims,” said the Swedish scientist.

Similar position expressed in its special statement and WHO - “to date, no consistent association has been established” between taking paracetamol and the occurrence of autism. “During pregnancy, any medicine should be taken with caution, especially in the first three months, and in accordance with the recommendations of health professionals,” the WHO reminds.

With colleagues according to and the FDA. “Although an association between acetaminophen and neurological conditions has been described in many studies, a cause-and-effect relationship has not been established. <…> Acetaminophen is the only over-the-counter drug approved for the treatment of fever during pregnancy, and high fever in pregnant women can pose a risk to their babies,” the agency said in a press release. 

Ann Bauer of the University of Massachusetts, co-author of the Mount Sinai study, told, that she was literally sickened by how the White House uses the rather neat conclusions presented in the article to promote conspiracy theories. The scientist emphasizes that her and her co-authors' recommendation was only that pregnant women use other methods of therapy (for example, cold compresses or massage) and resort to taking paracetamol only if these methods do not help and if the drug is recommended by the attending physician.

Are there other relevant studies linking paracetamol to neurodevelopmental disorders?

Attempts to conduct a systematic review, meta-analysis, or study with large samples have been made by other scientists. In 2018 such work published Israeli scientists - their sample included almost 133,000 pairs of mothers and their children. The researchers concluded that children whose mothers took paracetamol during pregnancy had a higher risk of ASD and ADHD than children whose mothers did not take it. However, this work still has the same limitations as other cohort studies: it is impossible to say for sure what caused the child’s problems - treatment, infection, or a combination of both. This is recognized by the authors themselves, who speak not of a cause-and-effect relationship, but of an association of two parameters.

In February 2025, an international group of researchers spent a systematic analysis of 56 earlier articles, including three meta-analyses (the selection overlaps with the review that attracted the attention of the White House). The scientists concluded that there is no need to change clinical guidelines for the use of paracetamol in pregnant women, as “prenatal exposure to acetaminophen is unlikely to result in a clinically significant increased risk of childhood ADHD or ASD.” 

Researchers were also interested in other potential adverse effects from taking paracetamol during pregnancy. So, Brazilian scientists focused on the risk of premature birth, delayed intrauterine weight gain and low birth weight - it turned out that the use of the drug had no effect on them. Scientists from Pennsylvania State University interested the effect of paracetamol on certain neurodevelopmental features characteristic of a number of disorders. They concluded that children whose mothers took the drug during pregnancy had only a higher risk of problems with sleep and attention.

Cover image: Mk2010, CC BY-SA 3.0, via Wikimedia Commons