The concern that taking Tylenol during pregnancy could raise a child’s risk of autism surged into the spotlight in September 2025 when President Donald Trump publicly advised against Tylenol use by expectant mothers—a warning that alarmed millions and spurred debate among doctors worldwide.
Now, a sweeping new review published in The BMJ says the scientific evidence does not support a clear causal link between maternal use of paracetamol or acetaminophen (the active ingredient in Tylenol) during pregnancy and the development of autism spectrum disorder (ASD) or attention deficit/hyperactivity disorder (ADHD) in children.
The study, led by researchers from the United Kingdom, analyzed data from nine systematic reviews that encompassed 40 primary studies. It found that while earlier reviews suggested a “possible to strong association,” most failed to account for key confounding factors—such as genetics, parental health, and shared family environments—that can influence neurodevelopmental outcomes.
“Existing systematic reviews on prenatal exposure to paracetamol and risk of autism and ADHD in offspring included heterogeneous studies, and many suggested a positive association,” the researchers wrote. “Our confidence in the findings of the reviews was low to critically low.”
Researchers say the controversy over Tylenol and neurodevelopment stems largely from observational studies. This type of research can identify correlations but not establish causation. Many of these studies relied on parental recall of medication use and didn’t adequately control for complex family or environmental influences.
Researchers took a step back, analyzing not only the results of those studies but also the quality of the reviews that summarized them. They found that seven of the nine reviews were rated “critically low” in reliability using the AMSTAR 2 tool, an international standard for assessing the reliability of systematic reviews. Only two met “low” quality standards, and none achieved moderate or high confidence ratings.
A crucial insight came from “sibling-controlled” studies in which researchers compared outcomes among brothers and sisters—one exposed to acetaminophen in utero, and another who was not.
These analyses, conducted in Sweden and Norway, found that the slight increases in autism or ADHD risk observed in broader population data disappeared entirely when family factors were taken into account.
For instance, in the Swedish study, the hazard ratio for ADHD dropped from 1.07 to 0.98 when adjusted for shared familial factors—essentially nullifying the link. Similarly, the risk for autism fell from 1.05 to 0.98.
To put it simply, the apparent connection between Tylenol and developmental disorders disappeared once genetics and household context were taken into account.
“Any apparent effect observed after in utero exposure to paracetamol on autism and ADHD in childhood might be driven by familial genetic and environmental factors and unmeasured confounders,” the researchers concluded.
In essence, it’s possible that the same family traits or medical conditions that increase the likelihood of mothers using Tylenol—such as fever, infection, or chronic pain—may also contribute to neurodevelopmental risk, independent of the medication itself.
Researchers also note that withholding Tylenol during pregnancy, particularly in cases of high fever, can carry its own dangers. Untreated fever has been linked to miscarriage, premature labor, and developmental complications. Thus, the team cautions against alarmist interpretations that could lead to avoidable harm.
The timing of this study is significant. The U.S. president’s September announcement advising against Tylenol use during pregnancy caused what researchers described as “considerable concern among pregnant women and mothers of children with autism.”
“Don’t take Tylenol if you’re pregnant, and don’t give Tylenol to your child,” President Trump said at a White House briefing. “Fight like hell not to take it.”
In the wake of the President’s remarks, even an eight-year-old social media post from Tylenol resurfaced and quickly went viral, adding to public confusion. The post suggested the company did not recommend taking “any of our products while pregnant.”
Tylenol’s parent company, Kenvue, later clarified that the 2017 post had been a reply to a now-deleted customer tweet and was “taken out of context and incomplete.” In a statement, the company emphasized that it did not reflect Tylenol’s longstanding guidance.
“To be clear: our full guidance on the safe use of Tylenol has not changed,” Kenvue said. “Our products are safe and effective when used as directed on the product label, and we recommend pregnant women do not take any over-the-counter medication, including acetaminophen, without talking to their doctor first.”
Health agencies around the world similarly echoed that clarification. The UK’s Medicines and Healthcare Products Regulatory Agency, the European Medicines Agency, and other national regulators issued statements reassuring the public that paracetamol remains the recommended treatment for pain and fever during pregnancy when used as directed. Their messages emphasized that guidance on the drug’s safety had not changed and that pregnant women should continue to follow medical advice rather than social media claims.
Those reassurances now appear supported by the latest evidence. Researchers emphasize that while continued research is warranted, current data do not justify changing clinical recommendations.
Still, the controversy highlights a growing challenge for science communication and how to convey scientific uncertainty without fueling misinformation.
Equally, the debate over Tylenol and autism also reflects the complexity of understanding autism’s origins. In September, The Debrief reported on a separate study suggesting that human brain evolution itself may explain the high prevalence of autism traits across modern populations.
That research proposed that the same genetic variations that enhance cognitive flexibility and creativity might also increase susceptibility to neurodivergent traits.
Taken together, these findings suggest that autism could arise from a deep interplay of genetics, evolution, and environment—not a single environmental exposure or parental choice.
As the researchers noted, the inclusion of parents and individuals with lived experience of autism and ADHD helped ensure that the review’s conclusions were both scientifically sound and socially responsible.
The patient contributors, including a mother and grandmother of children with autism, emphasized that recognizing familial and genetic links can “reduce misplaced blame and reassure families that neurodivergence in their children is not caused by anything the mother did during pregnancy.”
Ultimately, this new review reframes the Tylenol debate as a lesson in scientific nuance rather than a case of public panic. It reminds both policymakers and the public that association does not equal causation. That evidence, however unsettling, must be weighed against methodological rigor.
“Existing evidence does not clearly link maternal paracetamol use during pregnancy with autism or ADHD in offspring,” the researchers conclude.
“In the future, studies reporting the effects of paracetamol use in pregnancy on neurodevelopment in children should ensure both reliable assessment of exposure and rigorous ascertainment of outcomes, address bias due to confounding that includes indication bias, and prioritize adjustment for genetic and shared environmental factors, preferably through sibling cohorts,” the add.
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com