Using acetaminophen as directed during pregnancy does not increase a child’s risk of autism, attention-deficit/hyperactivity disorder (ADHD) or intellectual disability, a major new review published Friday finds.

Acetaminophen, also known as paracetamol and by the brand name Tylenol, is one of the most commonly used medications in pregnancy, with doctors often recommending it as the first option for pain or fever, but in limited use.

Earlier studies have produced mixed results, with some suggesting the drug may be associated with a raise in the risk of autism or ADHD in children, leaving some pregnant people unsure of how safe it is.

In the new meta-analysis, published in the journal The Lancet Obstetrics, Gynecology & Women’s Health, researchers reviewed results from about 60 studies.

They found no link to developmental disorders in children when expectant people used acetaminophen according to the label, in one of the most comprehensive evaluations of the evidence to date.

“The clearest takeaway is that the best-quality evidence does not support a causal link between taking paracetamol during pregnancy and autism or ADHD in children,” Dr. Asma Khalil, study co-author and professor of obstetrics and maternal fetal medicine at St. George’s Hospital in London, told ABC News.

“Pregnant women should feel reassured that paracetamol remains the recommended first-line option for pain or fever in pregnancy when used as directed,” she added.

In September, President Donald Trump warned that acetaminophen use in pregnancy was “associated with a very increased risk of autism” and the president advised pregnant women, “Don’t take Tylenol.”

The president has since repeated that claim on social media and has suggested that young children, including babies, shouldn’t be given the drug, without providing evidence to back up the statement.

The Food and Drug Administration also released a note at the time to doctors about a possible link between acetaminophen during pregnancy and autism. The note included language that there has been no evidence that Tylenol causes autism, and the association is an ongoing area of scientific debate.

In a statement to ABC News, HHS said, “many experts have expressed concern of the use of acetaminophen during pregnancy.”

Major medical groups reacted strongly, expressing concern that pregnant women may be discouraged from using acetaminophen even if they could benefit.

Kenvue, the maker of Tylenol, said at the time saying it believes that research shows that acetaminophen does not cause autism.

In a new statement to ABC News, Kenvue said it would review the new analysis upon publication.

“Our view of the existing science remains the same: we believe independent, sound science shows Tylenol is safe and taking acetaminophen does not cause autism,” the statement read.

The new review focused on sibling-comparison studies, which look at siblings born to the same mother when one pregnancy involved taking acetaminophen and another did not. Because siblings share genetics and family environment, this design helps separate the effects of the drug from family background.

In sibling-comparison analyses, exposure to acetaminophen during pregnancy was not associated with autism spectrum disorder, ADHD or any other intellectual disability. This conclusion held up even in studies with more than five years of follow-up, the authors said.

The authors said the review may help explain why earlier observational studies appeared to show a possible link between acetaminophen use in pregnancy and developmental disorders.

People do not take acetaminophen randomly but for symptoms such as fever, infection, inflammation or pain, the authors said. These symptoms may also be linked to the brain development of a fetus, making it possible to confuse the effects of the underlying condition with effects of the medication.

Jessica B. Steier, who leads the science communication group Unbiased Science and was not involved in the review, told ABC News that not treating symptoms, such as fever, could be harmful to both the pregnant person and the fetus.

“Untreated fever has documented associations with serious pregnancy and fetal risks,” she explained. “The alternative pain medications — NSAIDs, opioids — carry their own pregnancy risks. Acetaminophen remains the safest option when medication is needed.”

Steier added that studies linking acetaminophen use in pregnancy to autism or other conditions are vulnerable to misinterpretation and can be persuasive, especially when shared on social media.

An HHS official told ABC News that the new analysis “does not resolve an important public health question; it sidesteps it. By excluding the vast majority of relevant evidence, privileging one study design known to bias results toward the null, and misrepresenting statistical power, the authors engineer a finding rather than evaluate causality.”

Khalil said patients should use the lowest effective dose for the shortest amount of time and to seek medical advice if symptoms persist, are severe or recur — especially fever.

The authors said there are limitations to the review, including that few studies using sibling-based designs, which prevented the team from accounting for other variables that could influence the use of painkillers or lead to neurodevelopmental disorders.

However, they add the findings of the new review align with the guidance of several professional medical organizations, including the American College of Obstetricians and Gynecologists (ACOG).

ACOG advises using acetaminophen when needed, following the label instructions, seeking medical guidance when appropriate and paying attention to the symptoms that prompt the drug’s use. 

A recurring or high fever, severe pain or symptoms that aren’t improving during pregnancy can signal an underlying problem that needs medical attention, according to ACOG. 

“It’s always sensible to use paracetamol appropriately in pregnancy: the lowest effective dose for the shortest time, and avoid unnecessary prolonged use without medical review,” Khalil said. 

Radhika Malhotra, MD is an internal medicine-preventive medicine resident at Rutgers New Jersey Medical School and a member of the ABC News Medical Unit.

ABC News’ Youri Benadjaoud contributed to this report.