US Health Secretary Robert F. Kennedy Jr. plans to announce a link between autism and prenatal exposure to the popular over-the-counter pain and fever medicine Tylenol, sold generically as acetaminophen in the United States and paracetamol in the UK, the Wall Street Journal reported on Friday.
What does research say on acetaminophen use during pregnancy?
There is no firm evidence of a link between the use of the drug and autism. Recent studies have yielded conflicting conclusions on whether its use during pregnancy might create risks for a developing fetus.
A 2024 study of nearly 2.5 million children in Sweden found no causal link between in utero exposure to acetaminophen and neurodevelopmental disorders like autism spectrum disorder or attention deficit hyperactivity disorder.
A 2025 review of 46 earlier studies did suggest a link between prenatal acetaminophen exposure and increased risks of these conditions, but the researchers from the Icahn School of Medicine at Mount Sinai, Harvard University and others said the study does not prove the drug caused the outcomes. They advised that pregnant women should continue to use acetaminophen as needed, at the lowest possible dose and for the shortest possible period.
Large 2025 studies from Europe and Japan have suggested that what might appear to be small associations between prenatal acetaminophen use and neurodevelopmental disorders might actually be due to confounders, that is, other underlying factors - such as environmental conditions, parents' health and genetics, other medications the mothers may have been taking, and illness.
What are medical guidelines for pregnant women?
Acetaminophen/paracetamol is the recommended first-line medication for pain and fever during pregnancy in guidelines from the American College of Obstetricians and Gynecologists, Britain's Royal College of Obstetricians and Gynecologists, and other medical organizations.
Use of ibuprofen, naproxen and other nonsteroidal anti-inflammatory drugs in the third trimester can lead to birth defects, both societies warn.
Pregnant women should talk to their doctor if they plan to take any of these medications, ACOG advises.
What are risks of not reducing fever during pregnancy?
Untreated maternal fever and pain during fetal development can increase the risks of birth defects such as heart conditions, abdominal wall defects, and neural tube defects in which the brain and spinal cord do not form properly. Untreated pain and fever has also been linked with preterm birth, low birth weight, and miscarriage.
In pregnant women, untreated fever and pain can cause high blood pressure, dehydration, depression and anxiety, and other health problems.
Why is the subject in focus now?
Assertions of a potential link have been a focus of lawsuits brought by parents and autism activists in the United States against retailers, charging they failed to warn consumers that Kenvue's Tylenol and its generic versions could cause ADHD or autism.
In December 2023, a US federal judge struck a blow to hundreds of such lawsuits, barring expert witnesses from testifying after finding they lacked scientific evidence for their claims.
In August 2024, citing that ruling, the judge dismissed all the cases in federal court. A US appeals court is slated to hear arguments next month in an appeal of that ruling, court records show.
