The US Government yesterday linked the consumption of paracetamol with autism, despite there being no scientific evidence to support this association.
"Acetaminophen (paracetamol) may be associated with a very high risk of autism," stated the US President, Donald Trump, during a press conference where he was accompanied by the Secretary of Health, Robert F. Kennedy, a figure under scrutiny for his clear anti-vaccine stance.
Although he did not provide any data to support his claims, Trump made statements like this: "if you are pregnant, do not take Tylenol (a popular brand of paracetamol in the US). Do not take it," he said.
The President's assertions have been heavily criticized by the scientific community both within and outside the country.
The European Medicines Agency (EMA) released a statement at noon on Tuesday reminding that paracetamol can be safely used during pregnancy and that "there is no evidence" requiring changes to its usage indications. "Our recommendation is based on a rigorous analysis of available scientific data, and we have not found any evidence that taking paracetamol during pregnancy causes autism in children," the statement says.
Numerous healthcare professionals and scientific societies have expressed similar views.
"There is no scientific evidence supporting the US Government's statements regarding paracetamol and autism," stated Beatriz Salazar, member of the Neuropsychiatry Group of the Spanish Society of Hospital Pharmacy (SEFH).
Almost echoing her words is Pedro Viaño, a pediatrician and member of the Drug Committee of the Spanish Association of Pediatrics, who emphasizes that the "overwhelming majority of scientific evidence" supports the safety of paracetamol.
"Paracetamol is a widely used drug for many years with well-established safety studies," adds the pediatrician.
"There are many studies refuting this correlation [between paracetamol and autism], but the most important was a Swedish study of 2.4 million births (1995-2019) published in 2024, which used real sibling data and found no relationship between prenatal exposure to paracetamol and later autism, ADHD, or intellectual disability. This suggests that there is no causal effect of paracetamol on autism. This is reinforced by the absence of a dose-dependent relationship. There is no solid evidence or convincing studies suggesting a causal relationship, and conclusions drawn to the contrary are often motivated, lack evidence, and are not supported by the most robust methods to answer this question. I am exceptionally confident that there is no relationship," also stated Monique Botha, Associate Professor of Social and Developmental Psychology at Durham University (UK) in statements to SMC UK.
Paracetamol and acetaminophen are synonymous, two names for the same medication, clarifies Salazar. In the US, it is more common to use the latter term or directly Tylenol, a very popular commercial brand of the active ingredient.
This medication, one of the most widely used worldwide, is practically the only analgesic indicated during pregnancy and has demonstrated its safety extensively, as highlighted by the pharmacy specialist.
The Trump Administration's basis for linking paracetamol and autism is a recent study that established an association between the two factors in pregnant women. However, as Viaño clarifies, the mentioned research is a "preliminary study that should be analyzed with caution" as it does not differentiate between fundamental issues, such as the reason why women were advised to take paracetamol.
"It is a preliminary study that yields a result different from the overwhelming majority of scientific evidence and, therefore, should be analyzed with caution," warns the pediatrician, who points out that "the authors of the study do not contraindicate, let alone prohibit, the administration of paracetamol to pregnant women or children but rather emphasize the basic principles of medication administration to pregnant women: effective minimum dose, administration for the shortest possible time within the indication, and appropriate prescription for symptoms."
"Outside of this controversy, paracetamol has not shown at all to favor the onset of autism either in pregnant women or in young children, as it is a widely used drug for many years with well-established safety studies," he adds.
Leucovorin, another indication without evidence
Autism is a condition whose causes are still unknown. Evidence suggests a genetic predisposition, involving a wide range of genes, and that various external factors, whose role has not been uncovered, may contribute to its development.
In recent years, an increase in the prevalence of this condition has been described, although, as Viaño clarifies, the main reason for this increase could be a greater awareness of autism spectrum disorders by healthcare professionals and educators. "This would lead to earlier detection of the disorder and also to the identification of mild cases that would have previously gone undiagnosed." In any case, the role of other factors that could contribute to an increase in prevalence, such as exposure to toxins or the increase in maternal and paternal age, is also being investigated.
Viaño has pointed out that numerous studies have empirically demonstrated that systematic vaccination of children does not lead to the development of autism spectrum disorders, an association also mentioned by Trump.
In his meeting with the media, the President also suggested the use of leucovorin as a treatment for autism symptoms.
This active ingredient, as explained by Salazar, is an active form of folic acid, "a vitamin that is essential and involved in practically all neurological activities of the body and is recommended for all pregnant women to prevent neurological problems in the fetus."
Regarding its use as a possible treatment for autism, "there is also not enough scientific evidence," Salazar points out.
"Leucovorin (folinic acid) has been promoted as a 'treatment' for autism, but the evidence is weak," stated Andrew Whitehouse, Professor of Autism Research at the Kids Research Institute Australia, to SMC. "Some small-scale trials suggest possible mild improvements in behavioral outcomes, but these studies are limited by the small number of participants, inconsistent results, and lack of independent replications."
"At this time, science does not reach the necessary level to recommend leucovorin in the clinical treatment of autism. The field lacks large-scale, multicenter, and rigorously controlled trials that can confirm if the benefits are real, reproducible, and significant in daily life. In summary, leucovorin remains experimental. Current research is too limited and preliminary to draw solid conclusions, and enthusiasm far outweighs scientific evidence," he concluded.
The Autism Confederation Spain, representing the autism associative movement in our country, has expressed their "absolute rejection and concern" regarding the announcements made by the US Government and have emphasized that they "lack any scientific evidence and may pose a potential harm to global public health." "We alert national and international institutions to the risk of giving a platform to populist and outdated discourses that violate the rights and dignity of people with autism," they stated in a release.