Acetaminophen, known as paracetamol in Europe, is the generic name for Tylenol, the over-the-counter pain reliever and fever reducer. In September 2025, the Trump administration's Department of Health and Human Services came out with a statement that acetaminophen might increase the risk of autism in children whose mothers take it during pregnancy.

The claims were based on the findings of studies that reported small associations between acetaminophen use during pregnancy and an increased risk of autism.

The guidance from Health and Human Services (HHS) did not acknowledge the results of a 2024 Swedish study that found little risk of autism in siblings of children with autism, ADHD or intellectual disabilities.

Acetaminophen remains the medication recommended most often to pregnant women who have a fever or are in pain.

The design of these studies made their findings prone to certain biases, however. For example, the data collected for these studies did not compare outcomes between siblings whose mother only took acetaminophen during one of her pregnancies.

To overcome these blind spots, a team of European researchers recently conducted a large meta-analysis of findings on paracetamol use during pregnancy. They systematically reviewed data from 43 studies that compared the outcomes of siblings of more than a million children — 260,000 children who were evaluated for autism spectrum disorder; more than 335,000 children evaluated for attention-deficit hyperactivity disorder (ADHD); and more than 400,000 children evaluated for intellectual disabilities.

The results showed that using acetaminophen/paracetamol during pregnancy did not increase the risk of any of these conditions.

“The message is clear. Acetaminophen remains a safe option during pregnancy when taken as recommended,” Asma Khalil, the study's lead author and a professor of Obstetrics and Maternal Fetal Medicine at St. George's Hospital, University of London, said in a statement. Acetaminophen remains the medication recommended most often to pregnant women who have a fever or are in pain, she added.

Not taking acetaminophen for pain or a fever could put mother and baby at risk, especially if the maternal fever remains untreated.

The associations seen between acetaminophen use during pregnancy that were found could be explained by genetic predisposition or other maternal factors such as the source of the fever or pain, but not by acetaminophen itself. In fact, not taking acetaminophen for pain or a fever could put the mother and baby at risk, especially if the maternal fever remains untreated.

The new findings support the recommendations made by major medical associations around the world, including the American College of Obstetricians and Gynecologists. The researchers hope this analysis will end any skepticism about acetaminophen use during pregnancy.

“Pregnant women should feel reassured that they still have a safe option to relieve them of their symptoms,” said Khalil.

The recent meta-analysis and a related editorial are published in Lancet Obstetrics, Gynaecology and Women's Health.