A debate has emerged within the United States over the safety of paracetamol (acetaminophen or Tylenol) during pregnancy, despite a major review in The Lancet finding no evidence linking the drug to autism or ADHD. The review, published last week, directly countered claims made by some US officials, including former President Donald Trump, who previously suggested the common painkiller could harm fetal brain development. Health experts welcomed the findings, stressing that paracetamol should remain the first-line pain relief option for pregnant women and warning that the issue has become overly politicised, creating confusion for patients and clinicians alike.

The US Department of Health and Human Services has nonetheless maintained its concerns. A spokesperson cited earlier remarks by Dr. Andrea Baccarelli of Harvard’s School of Public Health, who has pointed to observational studies suggesting a possible association between paracetamol use in pregnancy and neurodevelopmental conditions. These studies, unlike clinical trials, observe population trends rather than establish causation. Such interpretations have been echoed by figures like Robert F. Kennedy Jr., who linked rising autism diagnoses to the drug—claims strongly disputed by much of the scientific community.

The Lancet review assessed 43 studies, placing particular emphasis on sibling-comparison research, which helps control for genetic and shared environmental factors known to influence autism and ADHD. By comparing siblings with different prenatal exposure to paracetamol, the researchers found no significant link between the medication and neurodevelopmental disorders. Many experts praised the review’s methodology as robust and reliable. Critics, including NIH director Dr. Jay Bhattacharya, argued that sibling studies can be limited and may underestimate risks by excluding families with uniform exposure patterns.

Responding to these criticisms, Professor Asma Khalil, lead author of the review, said the analysis systematically evaluated all available evidence while giving greater weight to study designs best suited to reducing bias. She noted that earlier reported associations consistently weakened or disappeared when more rigorous methods were applied. Khalil emphasized that the findings support existing clinical guidance and should reassure expectant mothers. Paracetamol remains widely used during pregnancy—by around half of pregnant women in the UK and nearly two-thirds in the US—even as autism diagnoses have risen sharply over the past two decades, a trend researchers say cannot be attributed to paracetamol use based on current evidence.