What to know
- In most cases acetaminophen (the active ingredient in Tylenol) and paracetamol products are the only approved painkillers for use during pregnancy.
- No high-quality scientific study exists that shows the use of these painkillers in pregnancy causes autism.
- Medical practitioners have urged pregnant women to seek advice from their trusted medical practitioners when considering appropriate pain relief.
“By September we will know what has caused the autism epidemic. And we’ll be able to eliminate those exposures.”
So said US Health Secretary in a televised meeting of US President cabinet in April 2025.
Fast forward to September and Kennedy, a vaccine skeptic who has previously promoted a scientifically dismissed connection between vaccines and , again flanked the president to announce safety label changes to the painkiller Tylenol, or specifically, its active ingredient acetaminophen, known outside of the US as paracetamol. Acetaminophen is currently the only painkiller in the US approved for use during pregnancy.
Neither Trump nor Kennedy said the drug causes autism spectrum disorder (ASD).
Rather they along with senior health officials pointed to a handful of studies that show an association between ASD and the use of acetaminophen by mothers during pregnancy. Some of these were included in statements issued by the White House and Department of Health and Human Services (HHS).
It didn’t stop Trump from telling America’s expectant mothers at least a dozen times . Scientist groups, health practitioners as well as autism advocacy and support bodies have expressed their concern at the president’s comments.
What do the studies cited by the Trump Administration say?
The White House and HHS cited five research publications in their announcements of the administration’s new policy directions.
Three of them were observational analyses, using data of several hundred births to explore if acetaminophen use during pregnancy led to adverse birth outcomes.
Only one of these specifically investigated ASD.
One published in the American Journal of Epidemiology in 2019 investigated acetaminophen use on attention deficit hyperactivity disorder (ADHD). It concluded that acetaminophen use “may influence neurodevelopment.”
Another published in Frontiers in Pediatrics in 2022 looked at adverse birth outcomes. It found an association may exist between acetaminophen use and low birthweight and decreased gestational age.
Both indicated that further research was required before drawing conclusions.
The sole investigation exploring autism as an outcome, published in JAMA Psychiatry in 2019, found an association with “significantly increased risk of childhood ADHD and ASD in a dose-response fashion” — where a higher dose would increase risk.
All three studies acknowledged limitations with their research that prevent definitive conclusions. DW reached out to the senior authors of the 2019 studies for comment but received declines from their affiliated institutions.
Another paper, published in BMC Environmental Health in 2025, reviewed 46 pieces of research for connections between acetaminophen and neurodevelopmental disorders. This included eight studies specific to autism. It concluded these studies were “consistent with an association between acetaminophen exposure during pregnancy and increased incidence of [neurodevelopmental disorders].”
Andrea Baccarelli, Dean of the Faculty at Harvard Chan School of Public Health (HSPH), was the senior author of this and the 2022 Frontiers study. In a statement provided to DW via HSPH, Baccarelli recommended “patients who need fever or pain reduction during pregnancy should take the lowest effective dose of acetaminophen, for the shortest possible duration, after consultation with their physician about their individual risk-benefit calculation.”
Baccarelli disclosed that he consulted with the Trump Administration prior to Monday’s announcement and that he was an expert witness in a case suing Johnson & Johnson, the manufacturer of Tylenol, for causing autism and ADHD in the plaintiffs’ children. His deposition noted that he was paid at least $150,000 (€128,000) for more than 200 hours of work. The evidence he provided for the plaintiffs was dismissed by the judge hearing the case. The judge’s opinion found Baccarelli “cherry-picked and misrepresented study results and refused to acknowledge the role of genetics.”
The final study cited by the Trump Administration is a consensus statement from an international group of researchers. That statement, published in Nature Reviews Endocrinology in 2021, has been controversial. While its authors have said they took care not to say acetaminophen causes autism, others warned the statement’s language could be misinterpreted.
Many experts have also pointed to a major American-Swedish study of more than 2.4 million births, published this year in the JAMA journal, which found “acetaminophen use during pregnancy was not associated with children’s autism, ADHD or intellectual disability.”
Association isn’t causation, and acetaminophen is a crucial pregnancy drug
While Trump — not a qualified clinician — offered his own opinion that pregnant mothers shouldn’t take acetaminophen during pregnancy, his health authorities have been more cautious.
Kennedy’s HHS acknowledged the “lack of clear causal evidence” on the issue. Other Trump health officials said pregnant women should consult with their doctor before taking the , and that clinicians would now be advised to administer “the lowest effective dose for the shortest duration when treatment is required.”
This is consistent with the recommendations of the consensus statement, Baccarelli’s opinion and other independent experts who have commented — and critiqued — the administration’s position.
David Moebjerg Kristensen, a researcher at Roskilde University and Copenhagen University Hospital in Denmark, was the senior author of the consensus statement. He told DW that while a growing body of research indicates an association between acetaminophen and autism, this is not a definitive cause-and-effect relationship.
“When it comes to autism, I would say no, we are not sure, and there’s a lot of discussions going on in the field, of trying to study this and trying to understand the problems,” Kristensen said.
He also said it would not be possible for a definitive clinical, randomized study to be conducted, due to ethical considerations.
“What we [the scientific community] are doing is using these observational studies, and there’s a lot of confounding effects,” he said. “For example, there’s a genetic component there that it [autism] runs in the family. This is one of these confounding effects.”
genetic causes account for around 4 in 5 cases of ASD and that the reason for spikes in case numbers is also due to widening definitions of the condition.
Ian Douglas, a Professor of Pharmacoepidemiology at the London School of Health and Tropical Medicine, UK, researches the risks and benefits of medications. He told DW the potential causes of pain during pregnancy that would prompt a woman to use the painkiller “themselves are associated with an increased risk of having a child with autism.”
What now?
Experts are concerned that the conflict between Trump’s personal recommendation and the stated advice from his health authorities creates a confusing set of information on the safe use of Tylenol for pregnant women,
The issued a statement emphasizing “there is currently no conclusive scientific evidence confirming a possible link between autism and use of acetaminophen.”
Kristensen and Douglas separately emphasized important points that are important context for the administration’s announcement.
First, there is no proof that acetaminophen use by pregnant women causes autism in their child. Some studies have found an association, others have not, and most researchers in the field acknowledge further research is required.
Second, acetaminophen is a pain killer medication, currently approved and considered safe to use as indicated. For certain pain-related conditions experienced during pregnancy, it is the only approved drug available.
Third, a careful understanding of its correct use is important. For that reason, pregnant women should always consult with their health practitioners before using the medication, or any medication.
“Go to your trusted sources of medical advice and information,” Douglas said. “Wherever you are, generally your local health service… will always have the best advice available, and the most up-to-date evidence, information without an agenda. I think that’s the important thing.”
The post Trump’s autism call: What the Tylenol science really says appeared first on Deutsche Welle.
