Paracetamol, known as Tylenol in the United States, is safe to use during pregnancy, European researchers said after reviewing evidence in response to claims made by Donald Trump linking the drug to autism.
In a review published on Saturday in The Lancet Obstetrics, Gynaecology & Women’s Health, researchers said they had compiled the highest-quality available evidence to assess the claims.
“Paracetamol is safe to use in pregnancy,” said lead author Asma Khalil, professor of obstetrics and maternal foetal medicine at City St George’s, University of London.
“The key message is reassurance: When used as recommended, the best available evidence does not support a causal link with autism, ADHD (attention-deficit/hyperactivity disorder) or intellectual disability,” Khalil said.
She added that patients had increasingly raised concerns about the drug after Trump, in September, advised pregnant women not to take it. At the time, national and international medical groups criticised the remarks, saying they were not supported by scientific evidence.
A spokesperson for the U.S. Department of Health and Human Services said in response that "many experts have expressed concern of the use of acetaminophen during pregnancy."
Recent studies have yielded conflicting conclusions on whether its use during pregnancy might create risks for a developing fetus. A 2024 study in Sweden found no causal link to disorders such as autism, while a 2025 review by U.S. researchers said there was a suggestion of a link. They advised that pregnant women should continue to use acetaminophen as needed, at the lowest possible dose and for the shortest possible period. Paracetamol/Tylenol is the only pain reliever considered safe for pregnant women, and doctors already advise them to use it with caution. Untreated, these conditions can be risky for both pregnant women and their babies. The European researchers conducted a systematic review and meta-analysis of existing data, finding 43 studies that were then assessed for quality and bias using a standard tool.
The team particularly focused on studies that looked at children born to the same mother who took paracetamol/Tylenol during one pregnancy but not the other. These take into account shared genetic factors and family environments that could be linked to autism or the other conditions studied, Khalil said.
There were only three studies of this type, but they were large, covering more than 260,000 children assessed for autism, and around 335,000 and 405,000 for ADHD and intellectual disabilities respectively.
ACCOUNTING FOR BIAS
They showed no significant link between use of the drug and any of the conditions studied. This remained the case when results from all of the high-quality studies that were assessed were pooled, the authors said. Khalil said much of the work showing a potential link, including the 2025 review of 46 studies cited by Trump officials, was prone to bias or confounding factors that her team's review had tried to account for. Grainne McAlonan, professor of Translational Neuroscience at King's College London, who was not involved in the research, praised the study, adding: “I hope the findings of this study bring the matter to a close.”
