Acetaminophen, the active ingredient in Tylenol, is the only pain relief and fever-reducing drug considered safe to take during pregnancy. More than half of pregnant people in the United States report using it at least once during their pregnancy.
Top federal health officials are now casting doubt on the safety of acetaminophen, warning that taking the drug during pregnancy could increase the risk of the child being born with autism.
At a White House event on Sep. 22, President Donald Trump urged pregnant people only to take acetaminophen if they can’t “tough it out.”
“Don’t take Tylenol. Don’t take it. Fight like hell not to take it,” Trump said.
On the same day, the Food and Drug Administration (FDA) issued a physician’s notice advising pregnant women to use acetaminophen only for high-grade fevers and said it would move to change the drug’s safety label, while acknowledging that existing studies don’t show causation for neurological conditions.
There are two decades of research on whether acetaminophen can affect children’s brain development. The evidence is conflicting—some studies show a link while others don’t. None has proven that acetaminophen causes autism.
Professional medical groups reiterated their longstanding recommendation for using acetaminophen when it’s needed to treat maternal fever, severe preeclampsia, and pain. If those conditions are improperly treated, it can lead to maternal and child health complications or death.
“The conditions people use acetaminophen to treat during pregnancy are far more dangerous than any theoretical risks and can create severe morbidity and mortality for the pregnant person and the fetus,” Steven Fleischman, MD, the president of American College of Obstetricians and Gynecologists (ACOG), said in a statement.
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The correlation between prenatal acetaminophen use and child brain development has never been tested in a clinical trial. Because of the known risks of maternal fever and severe pain, it would be unethical to withhold acetaminophen from pregnant people in a trial when there are no safe alternatives. That leaves scientists to make conclusions based on more observational evidence and animal studies.
The White House announcement followed the August publication of a research paper that reviews 46 studies on acetaminophen use during pregnancy, eight of which were focused on the link between acetaminophen and autism. The authors said that, taken together, the studies show that "a causal relationship is plausible" between prenatal acetaminophen and an increased risk for autism.
Ann Bauer, ScD, a University of Massachusetts epidemiologist and co-author of the paper, said the research isn't conclusive. Her team found that among studies that showed a positive association, taking acetaminophen for four weeks or longer appeared to have a bigger effect on autism risk.
"We believe the combined weight of animal and human scientific evidence is strong enough for pregnant women to be cautioned by health professionals against its indiscriminate use," Bauer told Verywell.
She said the research indicates that taking acetaminophen a few times during pregnancy is unlikely to be harmful. However, she added, healthcare providers should advise pregnant people to use acetaminophen only when medically indicated, to consult a physician or pharmacist before long-term use, and to take the lowest effective dose for the shortest possible time.
Many of the current studies ask mothers to self-report their acetaminophen use, which may lead to underreporting since the drug is an ingredient in many medications beyond Tylenol, said Brennan Baker, PhD, a postdoctoral scholar at Seattle Children’s Hospital.
In a 2025 paper, Baker’s team instead used biomarker tests to see if there is a relationship between the amount of acetaminophen in a mother’s blood and the risk of attention deficit and hyperactivity disorder (ADHD), another neurodevelopmental condition. That study found the relative risk of ADHD to be about three times higher in those with the greatest acetaminophen use.
Other factors that could skew the findings of studies on acetaminophen effects include the mother's health status, the baby's birth weight and health status, and other environmental exposures.
Steven Fleischman, MD
The conditions people use acetaminophen to treat during pregnancy are far more dangerous than any theoretical risks and can create severe morbidity and mortality for the pregnant person and the fetus.
— Steven Fleischman, MD
Conflicting and Incomplete Evidence
ACOG, the largest professional membership organization for obstetrician-gynecologists in the U.S., critiqued the August review for relying on low-quality evidence.
“Not a single reputable study has successfully concluded that the use of acetaminophen in any trimester of pregnancy causes neurodevelopmental disorders in children,” the ACOG said in a statement.
The organization instead highlighted a large 2024 study in Sweden that analyzed the rates of autism among siblings and found no significant difference when mothers used acetaminophen during one pregnancy but not another.
Autism is a hereditary condition, said Brian Lee, PhD, a professor of epidemiology at Drexel University and a senior author of the Sweden study. Some environmental factors, like pollution and pesticide exposure, may play a role, but genetics almost certainly do. By controlling for genetic and familial factors, his team found “the apparent risk completely flatlined and disappeared,” he said.
A large review of evidence published in February concluded that most of the studies reporting positive findings "are difficult to interpret because they have important biases." The authors say there's not yet enough evidence to change clinical recommendations and call for more prospective studies to better understand if acetaminophen impacts neurodevelopment.
"There's a lot of evidence being spouted. And as far as the quality of the evidence, let's just say that the quality isn't necessarily all high quality," Lee said. "It's almost certain that this is going to cause a lot more confusion when you're receiving fragmented and dissenting messaging from our public health officials. I would hope that personal physicians are able to cut through that noise and help their patients receive the best care that they can get."
The Administration's Hunt for a Cause
Trump called the rise in autism cases “one of the most alarming public health developments in history.” The Centers for Disease Control and Prevention (CDC) reported that 1 in 31 eight-year-olds was diagnosed with the condition in 2022, compared with 1 in 150 in 2000.
“Framing autism as having a single cause seriously oversimplifies the science and can feed stigma. It suggests autism is a ‘problem’ to be eradicated rather than a natural and valid form of human diversity,” Patty Laushman, certified autism life coach and founder of Thrive Autism Coaching, told Verywell in an email. “Hearing that the government’s priority is to ‘find a cause’ can feel like their existence is being pathologized.”
Federal agencies are pouring more resources into autism research. Jay Bhattacharya, director of the National Institutes of Health (NIH), announced that the agency’s autism data science initiative will spend $50 million to support 13 research projects into the root causes and potential treatments for autism. A separate NIH report on the causes of autism is expected soon.
“Parents already carry heavy emotional burdens regardless of their child's neurotype. Introducing speculation without solid evidence can reinforce self-blame,” Laushman said. “My message to parents is this: Autism is not your fault.”
When to Take Acetaminophen
The FDA's letter says "clinicians should consider minimizing the use of acetaminophen during pregnancy for routine low-grade fevers."
Maternal and fetal medicine groups already recommend that pregnant people use the drug in moderation or for the shortest duration when medically necessary and to consult with a doctor beforehand.
Baker said pregnant people should make sure they’re taking acetaminophen only when it will provide them relief. The drug is best at reducing fever and treating mild to moderate pain that doesn’t involve inflammation. For instance, clinical trials have shown acetaminophen to be ineffective in treating back pain and chronic pain conditions.
“It's possible people are taking the drug for conditions where it's not actually providing any relief. That shouldn’t be happening if there's even a possibility of this being a causal effect on adverse neurodevelopment,” Baker said.
Bauer said the best path forward is not to “make women suffer” by banning acetaminophen.
“We want to try to get women to stop taking it for nuisance pain, like if they have a slight headache,” Bauer said. “I think we live in a society in which the minute we have any discomfort, a lot of people pop a Tylenol or an Advil. And I think we need to start moving away from that.”
