() President Donald Trump discouraged pregnant women from taking Tylenol during a news conference on Monday, saying research needs to be done to see if there is a potential link between the pain reliever and higher autism risk.

Tylenol, whose active ingredient is acetaminophen, is a common pain reliever that doctors have long considered safe to use during pregnancy.

The president said Monday that the Food and Drug Administration will be notifying doctors that the use of acetaminophen “can be associated” with a “very increased risk of autism,” despite a lack of strong evidence supporting that claim.

“Taking Tylenol is not good,” Trump said, adding that pregnant women should limit Tylenol use “unless medically necessary,” like in the case of a high fever.

The American College of Obstetricians and Gynecologists disagrees with that assessment and reaffirmed the safety and benefits of acetaminophen for pregnant women shortly after Trump’s comments.

Dr. Steven Fleischman, president of the ACOG, called Monday’s announcement “irresponsible” and said it “dangerously simplifies the many and complex causes of neurologic challenges in children.”

“More than two decades of research have found no causal link between acetaminophen use during pregnancy and autism, ADHD, or intellectual disability in children,” the ACOG said in a statement.

The statement continued: “Acetaminophen continues to be an important and safe option for managing pain and fever in pregnancy conditions that can pose serious risks to pregnant patients and their fetuses if left untreated.”

Still, pregnant women should consult with their doctors, as with all medicines.

FDA Commissioner Dr. Marty Makary said Monday the agency is taking action to update the label on acetaminophen, warning pregnant women of the potential association between the drug and increased autism risk.

Health Secretary Robert F. Kennedy Jr. has made finding the causes of autism one of his key goals and said that work is ongoing.

“We are continuing to investigate a multiplicity of potential causes with no areas of taboo,” Kennedy said Monday.

What research is already out there on autism and pregnancy?

After years of research, scientists haven’t identified a single cause of autism, but a mix of factors appears to raise the risk, according to the Centers for Disease Control and Prevention.

Those include environmental, biological and genetic influences. For example, a child may be more likely to develop autism if they’re born to older parents, have a sibling with the condition, carry certain genetic or chromosomal traits or experience complications at birth, the CDC says.

“It’s very unlikely that we’re going to find one cause that’s causing all of the autism,” former CDC director Dr. Tom Frieden told earlier this month, noting that the condition exists on a spectrum.

Notably, childhood vaccines “do not cause autism,” and maternal vaccines have not been shown to cause autism, according to the Institute for Vaccine Safety at Johns Hopkins University.

As for acetaminophen, Frieden said the latest report is not based on new data but rather a new analysis of existing studies, and it suggests there “may be a role for Tylenol in some people who develop autism” but cautioned that the evidence is “far from definitive.”

Dr. Anita Patel, a pediatric critical care specialist, worries the Trump administration’s expected warning about Tylenol could backfire if it leads pregnant women to avoid the medication altogether.

“Uncontrolled fevers during pregnancy absolutely can cause harm,” Patel told on Sunday.

Frieden echoed that concern, calling it a “really tough problem” because other painkillers are “definitely not safe during different parts of pregnancy.” He urged women to consult with their doctors.

Why are autism diagnoses on the rise?

Autism diagnoses have increased over the years, a challenge Kennedy has called an “epidemic,” but the reasons are complicated.

According to the CDC’s latest report, about 1 in 31 (3.2%) 8-year-old children were identified with autism across 16 Autism and Developmental Disabilities Monitoring network communities in 2022. That’s up from the previous estimate of 1 in 36 as recently as 2020 and 1 in 150 in 2000.

Put another way: That’s a roughly 300% increase in autism diagnoses over the past 20 years or so.

Researchers largely attribute the rise to two main factors: a broader definition of autism spectrum disorder and more widespread screening.

In other words, more people are meeting today’s definition of autism than previously, and parents and doctors have become more aware of the early warning signs.

Still, the steady increase has researchers asking whether broader societal changes might also be playing a role a question that remains under study. One known factor: The average age of mothers at childbirth has risen, and older parental age is one of the most consistently identified risk factors for autism.

One major study published last year detected a small association between prenatal acetaminophen use and autism, but that link disappeared in sibling comparisons, suggesting other factors, not the drug, may be driving the marginal increase in risk.

“We never want to assume that just because two things are correlated that one causes the other,” Dr. Krupa Playforth, a board-certified pediatrician, told on Monday.

In a separate study, researchers analyzed results from 46 previous studies and found that when children are exposed to acetaminophen during pregnancy, they may be more likely to develop neurodevelopmental disorders, including autism and ADHD.

Rather than recommend a “broad limitation,” the researchers suggested “judicious acetaminophen use,” meaning the lowest effective dose for the shortest duration.

In its label-change announcement on Monday, the FDA said some studies suggest the acetaminophen risk may be most pronounced when it’s taken “chronically” throughout pregnancy. The agency said multiple studies, including the Nurses’ Health Study II and the Boston Birth Cohort, have suggested a correlation between acetaminophen use during pregnancy and subsequent diagnosis of conditions like autism and ADHD.

However, the FDA acknowledged that no “causal relationship” has been established between acetaminophen and neurological conditions.

Dr. Makary said it remains reasonable for pregnant women to use acetaminophen “in certain scenarios.”  

OB-GYN recommendations for pregnant women

Dr. Jamil Abdur-Rahman, a board-certified obstetrician and gynecologist in Chicago, is concerned that Monday’s Tylenol announcement could make patients hesitant to use one of the only safe pain medications for pregnancy.

“Tylenol is really one of the only go-to options that we have,” Abdur-Rahman said ahead of Trump’s announcement. “It can really be important to reduce fevers in pregnancy.”

Like others, he worries that Tylenol-skepticism could cause some to endure fevers unnecessarily or turn to unsafe non-steroidal anti-inflammatory drugs like ibuprofen.

“If there’s even a hint that there could be an issue, I think that they will avoid [Tylenol], and that too could lead to a lot of issues,” Abdur-Rahman said.

So long as the ACOG says Tylenol is still safe to use, Abdur-Rahman said he would feel comfortable recommending it.

Dr. Patel agreed and doesn’t think pregnant women need to pause before taking Tylenol, but said that everyone should discuss any medication they take with their doctors.

The Society for Maternal-Fetal Medicine has also said pregnant women can use acetaminophen when pain and fever relief are needed after consulting with their doctor.

“At this time, the weight of scientific evidence that acetaminophen use during pregnancy causes an increased risk for autism or ADHD is simply inconclusive,” Dr. Sindhu Srinivas, an OB/GYN, said in a statement earlier this month.