Pregnant women across the globe have long turned to paracetamol—known as acetaminophen in the United States and sold under the brand name Tylenol—to manage common ailments like headaches, fevers, and aches. But mounting evidence from a recent international research collaboration is urging a more cautious approach, with Harvard and Mount Sinai scientists warning that prenatal exposure to this ubiquitous painkiller may increase the risk of autism and attention deficit hyperactivity disorder (ADHD) in children.
The warning, published on August 23, 2025, in the journal Environmental Health and reported by multiple outlets including GazetaExpress, The Sun, and Times Now, comes after a comprehensive analysis of more than 100,000 participants across 46 separate studies. Researchers from the Icahn School of Medicine at Mount Sinai and Harvard T.H. Chan School of Public Health applied the Navigation Guide Systematic Review methodology—a gold-standard framework for evaluating environmental health data. Their findings, described as the "strongest evidence yet," suggest a consistent association between prenatal acetaminophen use and increased risks of neurodevelopmental disorders, most notably autism and ADHD.
Dr. Diddier Prada, associate professor of population health sciences at Mount Sinai Hospital and co-author of the study, explained to the Mail, "Our results indicate that higher-quality studies are more likely to show an association between prenatal exposure to acetaminophen and increased risk for autism and ADHD." He added a sobering note: "Because this drug is so widely used, even a small increase in risk could have major public health consequences."
The research team meticulously gathered data on when paracetamol was taken—whether in the first, second, or third trimester, or throughout the entire pregnancy—and linked this information to mothers' and children's medical records. According to the study, "The results suggest strong evidence for a possible relationship between prenatal acetaminophen use and increased risk for ADHD in children. This includes high-quality studies that provide very strong evidence of an association and studies that provide strong evidence of an association." They also found "strong evidence for a relationship between prenatal acetaminophen use and increased risk of autism in children."
Yet, the researchers are quick to clarify that their findings do not prove causation. Instead, they highlight a consistent and concerning link that warrants further investigation. As Dr. Prada emphasized, "Pregnant women should not stop taking medication without consulting their doctors. Untreated pain or fever can also harm the baby. Our study highlights the importance of discussing with healthcare professionals the safest approach and considering non-medical alternatives when possible."
Current guidelines from the UK's National Health Service (NHS) recommend paracetamol as the "first choice" painkiller for pregnant women, but only for short periods and at the lowest effective dose. In Britain, about half of pregnant women report using paracetamol, while in the US, that figure climbs to roughly 65%.
The advice from the Harvard and Mount Sinai team is clear: use paracetamol judiciously during pregnancy—only at the lowest effective dose, for the shortest possible duration, and always under the guidance of a healthcare professional. As the researchers put it, "We recommend judicious acetaminophen use—lowest effective dose, shortest duration—under medical guidance, tailored to individual risk-benefit assessments, rather than a broad limitation."
This latest analysis aligns with findings from European studies, such as one led by the Barcelona Institute for Global Health, which tracked 70,000 children across six countries. That research found children exposed to paracetamol in the womb were 19% more likely to develop autism and 21% more likely to display ADHD symptoms. Notably, the effect was observed in both boys and girls. However, scientific opinion remains divided. While a 2019 study of nearly 5,000 children suggested mothers who used paracetamol during pregnancy were 20% more likely to have a child with ADHD, a massive Swedish study involving 2.5 million children found no significant link to ADHD, autism, or learning problems. Professor Renee Gardner, who led the Swedish research, advised expectant mothers to always follow their doctor’s advice.
Adding to the complexity, a study from the University of Washington tested blood samples from 307 pregnant women and found that children exposed to paracetamol in the womb were more than three times as likely to develop ADHD by ages 8 to 10, even after accounting for family history and other factors. Lead author Dr. Brennan Baker noted that many people may not realize paracetamol is present in a range of over-the-counter medicines, making accurate reporting of exposure challenging.
The backdrop to these findings is a surge in demand for autism and ADHD diagnostic services. NHS figures reveal that nearly 130,000 minors under 18 in England were awaiting autism assessments in December 2024—a record high that experts have described as an "invisible crisis." At the same time, more than 230,000 people in England are now prescribed ADHD medication, with prescription rates surging by 20% in 2024 alone, mainly among women in their 20s and 30s. In the US, the Centers for Disease Control and Prevention (CDC) report that autism diagnoses have increased from 1 in 150 children in 2000 to 1 in 31 by 2020—a nearly fourfold rise. A 2024 study analyzing 12.2 million American health records showed a 175% increase in autism diagnoses over 11 years, reflecting both heightened awareness and evolving diagnostic criteria.
Despite these trends, experts caution against knee-jerk reactions. As Dr. Prada and others have reiterated, untreated pain or fever during pregnancy can also pose risks to the developing fetus. The NHS and other health authorities continue to recommend paracetamol as a safe option when used appropriately, but stress the importance of individualized medical advice—especially for those with pre-existing conditions like epilepsy, liver, or kidney disease.
The debate over paracetamol’s safety in pregnancy is far from settled. While some researchers point to the consistency of associations across high-quality studies, others highlight conflicting evidence and the need for more rigorous, longitudinal research. What is clear, however, is that the issue is of growing public health importance, given the widespread use of paracetamol among pregnant women worldwide and the rising prevalence of neurodevelopmental disorders.
For now, the message from leading scientists is one of caution and consultation: expectant mothers should not stop taking paracetamol abruptly, but should work closely with their healthcare providers to weigh the benefits and risks, using the lowest dose for the shortest time necessary. As the science continues to evolve, so too will the guidance—but the call for vigilance is louder than ever.
