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US President Donald Trump claimed that pregnant women’s use of paracetamol is linked to a risk of babies developing autism. The administration also announced that the FDA would soon approve leucovorin, a drug traditionally used by cancer and anaemia patients, to be used as treatment for children with autism.
The All Ireland Science Media Centre asked local experts to comment. Our colleagues at the Australian, New Zealand, and UK Science Media Centres have also gathered comments.
Professor Geraldine Leader & Dr. Sally Whelan (Post Doctoral Researcher), Irish Centre for Autism & Neurodevelopmental Research, Institute for Lifecourse and Society, University of Galway, comment:
Comment on behalf the Irish Centre for Autism & Neurodevelopmental Research:
“Pregnant women should continue to use paracetamol when they need to, under existing guidelines and the advice of their healthcare professionals and pharmacists. It is necessary to treat some illnesses when pregnant using paracetamol within recommended guidelines and women should not be afraid to continue doing this.
“Autism occurs due to a combination of genetic and environmental factors. It is incorrect to suggest that one factor such as taking paracetamol in pregnancy causes autism. Some studies have found that when pregnant women use paracetamol there is also an increased likelihood of a child being autistic. However, this should not be interpreted that paracetamol usage causes autism. It could, for example, be the underlying illness or fever that increases the likelihood of autism and not the paracetamol. Evidence from research studies that have controlled for other confounding factors suggests that there is no relationship between paracetamol usage in pregnancy and the likelihood of a child being autistic.
“Leucovorin is already an approved medicine for other conditions (like certain types of anaemia or as a “rescue” drug after chemotherapy). Some autistic children can have trouble getting enough folate (a type of vitamin B9) into their brains, even if their blood folate levels are normal. This problem can be caused by the body making certain antibodies (called FRAA). When these antibodies block folate from entering the brain they can cause cerebral folate deficiency. Leucovorin is a form of folate that can get past this block. By doing so, it may help raise folate levels in the brain.
“Some research, including clinical trials and case reports, suggest that leucovorin can help with language, communication, and some behaviours, especially in autistic children who test positive for FRAA. However, not all children benefit, some show improvements, while others do not. Side effects from the Leucovorin are usually mild. Therefore, Leucovorin is a promising potential targeted treatment for some autistic children who have folate pathway problems (especially if they have FRAA-antibodies). It is not, as suggested by President Trump, a cure for autism. Evidence suggests that leucovorin could be used cautiously alongside other therapies and its use should ideally be guided by biomarker testing. The evidence for Leucovorin is promising but still limited, so treatment should be carefully supervised, closely monitored, and tailored to the individual child until larger, more definitive studies are completed.”
Dr Jeffrey Glennon, Assistant Professor at University College Dublin School of Medicine / Conway Institute, comments:
“Autism affects around 1 in 100 people in Ireland with autistic traits occurring in 1 in 65 people. There are media reports that use of paracetamol (also known as acetaminophen) during pregnancy may constitute a risk factor for autism spectrum traits. This is incorrect.
“A recent large scale landmark study by both Swedish and U.S. researchers in 186,000 people demonstrated no link between paracetamol use by expectant mothers and autism spectrum traits in their offspring. This study, led by Prof. Gardner and Prof. Lee was funded by the U.S. National Institute of Health and published in 2024. What makes this study convincing is the researchers examined registry data for 2.4 million Swedish-born children between 1995 and 2019. They then combined the prescription register and reports to midwives during pregnancy to study the nearly 186,000 children whose mothers were treated with paracetamol during pregnancy. These children were compared with their own brothers and sisters in cases where the mother had not been treated with paracetamol when she was pregnant with them. They concluded that there was no evidence of a link between maternal paracetamol use and autistic traits.”
Declarations of interest:
Prof Geraldine Leader & Dr Sally Whelan: “We do not have any conflicts of interest that would impact our ability to comment independently.”
Dr Jeffrey Glennon: “No conflicts of interest.”