No Link Found Between Paracetamol Use in Pregnancy and Autism, ADHD, or Intellectual Disability

A large-scale systematic review and meta-analysis published in The Lancet Obstetrics, Gynaecology and Women's Health has found no evidence that using paracetamol (also known as acetaminophen or Tylenol) during pregnancy increases the risk of autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), or intellectual disability in children. The findings counter previous claims suggesting a potential link.

Study Overview

An international team of seven researchers from the UK, Italy, and Sweden, led by Professor Asma Khalil (City St George’s, University of London), conducted the review. The team evaluated 43 existing studies from an initial pool of thousands, focusing on those with the strongest methodological quality.

Key study populations analyzed included:

• 262,852 children assessed for autism
• 335,255 children assessed for ADHD
• 406,681 children assessed for intellectual disability

Methodology

The researchers prioritized sibling-comparison studies. This design compares siblings born to the same mother—where paracetamol was used in one pregnancy but not the other—to control for shared genetic factors and family environment. Three such high-quality sibling studies were identified and analyzed.

Excluded from the final analysis were studies that:

• Lacked comparison groups
• Did not disclose women's health histories or medications
• Relied solely on self-reported Tylenol use and autism diagnoses

Only studies using medical records or healthcare provider-reviewed questionnaires were included.

Key Findings

Across all analytical methods, the review found no association between maternal paracetamol use during pregnancy and an increased risk of autism, ADHD, or intellectual disability.

The authors noted that previously reported associations in earlier observational studies may have been influenced by:

• Genetic factors and family environment
• Underlying maternal health conditions (such as fever or pain) for which paracetamol was taken
• Methodological biases in earlier research

Context of Previous Claims

In September 2025, former US President Donald Trump publicly advised pregnant women to avoid Tylenol, citing an "increased risk of autism." Health Secretary Robert F. Kennedy, Jr. also made statements linking acetaminophen use during pregnancy to autism. These assertions were criticized by medical and scientific organizations globally.

The US Food and Drug Administration (FDA) issued a note to physicians in September 2025 advising them to "consider minimizing the use of acetaminophen" but also stated that the drug remains the safest over-the-counter option for pain and fever during pregnancy. The FDA described the association with autism as "an ongoing area of scientific debate" and has not updated the safety label for acetaminophen.

Expert and Official Responses

Professor Asma Khalil stated that paracetamol remains a safe, first-line medication for pain or fever during pregnancy when taken as directed. She advised using the lowest effective dose for the shortest possible duration and seeking medical advice if symptoms persist.

Health and Human Services (HHS) Spokesperson Andrew Nixon expressed concern about the review's methodology, stating it "sidesteps" important public health questions by excluding most relevant evidence. An HHS official said the FDA still plans to update the safety label for acetaminophen to warn about "prenatal exposures and child development."

Dr. Caleb Alexander (Johns Hopkins Bloomberg School of Public Health) commented on a separate study showing a 10% decline in emergency room orders for acetaminophen for pregnant patients following the president's statements, noting the influence of statements from figures with large audiences on prescriber and patient behavior.

Autism researchers, including Alycia Halladay (Autism Science Foundation), suggested the question has been answered and that focus should shift to other causes. David Trembath (CliniKids, The Kids Research Institute Australia) expressed hope the findings would resolve concerns and encourage reliance on medical professionals for clear, consistent evidence.

Medical experts not involved in the research, including Professor Grainne McAlonnan (King's College London), Professor Ian Douglas (London School of Hygiene and Tropical Medicine), and Professor Jan Haavik, commended the study's methodology and anticipated it would reduce anxiety among expectant mothers.

Kenvue, the manufacturer of Tylenol, has stated there is no credible data supporting a link between acetaminophen use and autism.

Health Guidance

Medical organizations including the American College of Obstetricians and Gynecologists (ACOG) advise:

• Using acetaminophen as needed, following label instructions
• Seeking medical guidance for persistent or severe symptoms
• Noting that high fever or unresolving pain can indicate an underlying issue requiring medical attention

Health authorities note that untreated fever or severe pain during pregnancy can pose risks to both mother and baby, including potential increases in the likelihood of miscarriage, premature birth, or developmental problems. Paracetamol is classified as a category A medication during pregnancy in Australia, indicating no proven increase in harmful effects on babies.

Separate Developments

On April 17, 2026, Health Secretary Robert F. Kennedy Jr. rejected the findings of a separate study published in JAMA Pediatrics that used medical records from over a million women in Denmark and found no link between acetaminophen use during pregnancy and autism. Kennedy called the study "garbage" and "fraudulent," arguing it was limited by its use of prescription data, which would not capture over-the-counter use.

The published study acknowledged that low-level, non-prescription use might be underestimated but cited previous research suggesting such bias is largely negligible.