Large sibling studies and a 2026 Lancet review find earlier concerns were driven by flawed data, not causal risk.
For years, many expecting parents—especially those navigating pregnancy without consistent access to medical care—have faced conflicting headlines about whether taking acetaminophen (commonly sold as Tylenol) could increase the risk of autism or ADHD in children. New, high-quality research published in late 2025 and early 2026 brings much-needed clarity: there is no credible evidence that acetaminophen use during pregnancy causes autism, ADHD, or intellectual disability.
The shift matters. Acetaminophen is widely used to treat fever and pain during pregnancy, conditions that—if left untreated—can pose real risks to fetal development. The latest findings reinforce guidance long maintained by leading medical organizations and help correct years of confusing or incomplete reporting.
What the New Research Shows
A major systematic review published in The Lancet in January 2026 analyzed more than 40 prior studies on prenatal exposure to paracetamol (the international name for acetaminophen). After evaluating study quality and methodology, the authors found no causal link between acetaminophen use during pregnancy and neurodevelopmental disorders.
Crucially, several of the most rigorous studies used sibling-comparison designs, a method considered the gold standard in observational research. One large Swedish study examined health data from approximately 2.5 million children and compared siblings born to the same mother, where one pregnancy involved acetaminophen use and another did not. When genetic and shared environmental factors were controlled for, the previously reported associations with autism and ADHD disappeared.
Researchers pointed instead to “confounding by indication”—meaning the underlying reason for taking the medication, such as infection or high fever, was likely the real risk factor observed in earlier studies.
Why Earlier Warnings Fell Short
Some public concern traces back to smaller observational studies, including a 2019 analysis by researchers at Johns Hopkins University, which reported an association between acetaminophen exposure and developmental outcomes. However, experts now note these studies relied heavily on self-reported medication use and did not adequately account for family history, maternal illness, or genetics.
“The newer studies answer questions the earlier ones could not,” said epidemiologists writing in The Lancet, emphasizing that association does not equal causation.
Medical Consensus Remains Clear
The American College of Obstetricians and Gynecologists (ACOG) continues to recommend acetaminophen as the first-line treatment for pain and fever during pregnancy. ACOG and other professional bodies warn that untreated fever—often caused by infection—can itself increase risks to the developing fetus.
The guidance is straightforward: use the lowest effective dose for the shortest necessary time and consult a healthcare provider when possible.
For families already navigating pregnancy amid language barriers, misinformation, or limited healthcare access, the updated evidence offers reassurance grounded in science—not speculation.
