Scientists find no link between Tylenol and autism, again, after Trump warning

Key Points:

• A large study analyzing over 700,000 mother-child pairs in Hong Kong found no link between prenatal acetaminophen (Tylenol) use and autism or ADHD, using a sibling-matched design to account for genetic and environmental factors.
• This study refutes claims made by President Trump and Robert F. Kennedy Jr., who had asserted without evidence that acetaminophen use during pregnancy causes autism, leading to a decline in its use and legal actions like a Texas lawsuit against Tylenol’s maker.
• Researchers noted that associations seen without sibling controls likely reflect familial confounding rather than a true pharmacologic effect, as similar associations appeared in negative control analyses involving acetaminophen use outside pregnancy.
• The findings align with previous sibling-matched studies from Sweden (2024) and Japan (2025), reinforcing that acetaminophen is safe for use during pregnancy and that untreated fever poses greater risks to fetal development.
• Medical organizations continue to emphasize acetaminophen’s safety during pregnancy and caution against avoiding treatment for fever or pain, which can increase risks of miscarriage, birth defects, premature birth, and neurodevelopmental disorders.