Trump resurrects unscientific theories linking paracetamol to autism; organizations deny it

US President Donald Trump once again resorted to conspiracy theories when, at a White House press conference, he linked autism diagnoses in children to paracetamol use during pregnancy. The hypothesis, repeated by the Republican, has no scientific basis, according to global health authorities.

Trump stated that the FDA (the regulatory agency equivalent to Anvisa) is considering changes to the labeling of Tylenol—the most popular brand of the drug in the country. Pharmaceutical company Kenvue, which manufactures the product, immediately responded: "There is no scientific basis" for the claims. Following the president's remarks, the company's shares fluctuated.

The international response was swift. The World Health Organization (WHO) stressed that there is no evidence to support the theory. "Existing research remains inconsistent," said spokesperson Tarik Jašarević. The European Medicines Agency and the UK regulatory authority also reinforced that paracetamol remains considered safe during pregnancy, as long as it is used in moderate doses and frequency. The known risk, they point out, is liver overload, not malformations or autism.

What the studies say

Trump's remarks echo studies already questioned by the scientific community. A 2015 Danish study suggested a 50% higher risk of autism among children of women who used paracetamol during pregnancy. In 2025, a review of about 40 studies published in the journal Environmental Health reinforced this hypothesis. Both studies, however, have been criticized for methodological flaws and an inability to prove cause and effect.

More recently, a Swedish study published in 2024 in JAMA analyzed genetic and familial factors and concluded that there is no association between paracetamol during pregnancy and an increased risk of autism, ADHD, or intellectual disability. The scientific consensus today is that the evidence for a correlation remains tenuous.

Supposed 'cure'

Trump also mentioned leucovorin, an active form of folic acid, as a possible treatment for autism. The substance is already used in cancer therapies, but its effects on the autism spectrum have not yet been proven in robust studies. So far, clinical trials are small and inconclusive.

Vaccines in the spotlight

Alongside Robert F. Kennedy Jr., his administration's health secretary and a figure known for his anti-vaccine stance, Trump used the press conference to advocate for changes to the childhood vaccination schedule and reiterate the false idea that vaccines cause autism.

The WHO reacted vehemently. "Vaccines save lives. We know that. Vaccines don't cause autism," Jašarević declared. The spokesperson also warned that postponing or changing immunization schedules without scientific basis significantly increases the risk of outbreaks, affecting not only children but the entire community.

Autism, experts point out, is a neurodevelopmental disorder—the autism spectrum disorder (ASD)—that manifests in diverse forms and whose origins are linked to complex genetic and environmental factors. No study to date has established a causal relationship between vaccines and ASD.

(with information from AFP)