There is no association between using acetaminophen (Tylenol) during pregnancy and the risk of autism spectrum disorder (ASD) or attention-deficit hyperactivity disorder (ADHD) in children, according to a study published today in JAMA Internal Medicine. It adds to the evidence highlighting acetaminophen’s safety during pregnancy.
“Paracetamol (acetaminophen) remains a safe and essential analgesic [pain reliever] and antipyretic [fever reducer] during pregnancy, whereas alternatives, such as NSAIDs [non-steroidal anti-inflammatory drugs] and opioids carry well-documented risks,” wrote the University of Hong Kong–led research team.
“Unwarranted reluctance to use paracetamol could lead to undertreatment of pain and fever, or the use of more harmful alternatives, both posing risks to the pregnancy and developing fetus,” they added.
Safe when taken as clinically indicated
The researchers used electronic health records from the Hong Kong Hospital Authority to identify pregnancies in which the mother received an acetaminophen prescription and then created a group of mother-child pairs from January 2001 through December 2023. The final group included mothers who had another child, thus creating a sibling matched cohort.
The researchers examined 124,333 children (61,775 girls [49.7%] and 62,558 boys [50.3%]) for autism. Being exposed to acetaminophen during pregnancy did not increase the risk of having an ASD diagnosis.
They also looked at 97,285 children (48,455 girls [49.8%]) and 48,830 boys [50.2%]) for ADHD. Again, there was no increased risk of an ADHD diagnosis in children born to mothers who took acetaminophen during pregnancy.
Unwarranted reluctance to use paracetamol could lead to undertreatment of pain and fever, or the use of more harmful alternatives, both posing risks to the pregnancy and developing fetus.
While the study reinforces the safety of taking acetaminophen during pregnancy, the researchers did not look at children whose mothers took over-the-counter Tylenol rather than the prescription medication.
“Clinicians should reassure patients that paracetamol [Tylenol] is safe when used as clinically indicated, at the lowest effective dose for the shortest necessary duration,” the authors wrote.
Tylenol ‘among the most used’ drugs in pregnancy
During a 2025 press conference, President Donald Trump said, without new evidence, that pregnant women should stop using acetaminophen because of its alleged relationship to autism.
“This was concerning given that acetaminophen is among the most used medications in pregnancy for the management of pain and fever, in part because alternative options are limited or contraindicated,” Brian K. Lee, PhD, of Drexel University, and Viktor H. Ahlqvist, PhD, of Aarhus University in Denmark, wrote in an accompanying commentary.
The president’s comments reduced pregnant women’s willingness to take acetaminophen. Two recent papers, one published in The Lancet and the other in Pediatrics, found that fewer pregnant women took the medication after hearing the unsupported claims.
Since then, an umbrella review and a nationwide Danish study found no association between maternal acetaminophen use and an increased risk of autism.
“Taken together with prior evidence from Japan, Norway, Sweden, and Taiwan, these findings from Hong Kong further reinforce the conclusion that acetaminophen use during pregnancy is unlikely to increase the risk of ASD or ADHD in exposed children,” Lee and Ahlqvist wrote.
They also noted that underfunding of research examining drug safety during pregnancy has resulted in a dearth of data on various medications’ impact on pregnant women and their children.
“Evidence on medication safety in pregnancy is typically generated only after widespread clinical use, because pregnant individuals are excluded from clinical trials,” they wrote. “This reactive and ad hoc paradigm is suboptimal given that timely, high quality evidence is essential to inform clinical decision making.”
