New York, NY (August 14, 2025) – Researchers at the Icahn School of Medicine at Mount Sinai have found that prenatal exposure to acetaminophen may increase the risk of neurodevelopmental disorders, including autism spectrum disorder and attention-deficit/hyperactivity disorder (ADHD), in children. The study, published today in BMC Environmental Health, is the first to apply the rigorous Navigation Guide methodology to systematically evaluate the rigor and quality of the scientific literature.
Acetaminophen (often sold under the brand name Tylenol®, and known as paracetamol outside the United States and Canada) is the most commonly used over-the-counter pain and fever medication during pregnancy and is used by more than half of pregnant women worldwide. Until now, acetaminophen has been considered the safest option for managing headache, fever, and other pain. Analysis by the Mount Sinai-led team of 46 studies incorporating data from more than 100,000 participants across multiple countries challenges this perception and underscores the need for both caution and further study.
The Navigation Guide Systematic Review methodology is a gold-standard framework for synthesizing and evaluating environmental health data. This approach allows researchers to assess and rate each study’s risk of bias, such as selective reporting of the outcomes or incomplete data, as well as the strength of the evidence and the quality of the studies individually and collectively.
“Our findings show that higher-quality studies are more likely to show a link between prenatal acetaminophen exposure and increased risks of autism and ADHD,” said Diddier Prada, MD, PhD, Assistant Professor of Population Health Science and Policy, and Environmental Medicine and Climate Science, at the Icahn School of Medicine at Mount Sinai. “Given the widespread use of this medication, even a small increase in risk could have major public health implications.”
The paper also explores biological mechanisms that could explain the association between acetaminophen use and these disorders. Acetaminophen is known to cross the placental barrier and may trigger oxidative stress, disrupt hormones, and cause epigenetic changes that interfere with fetal brain development.
While the study does not show that acetaminophen directly causes neurodevelopmental disorders, the research team’s findings strengthen the evidence for a connection and raise concerns about current clinical practices.
The researchers call for cautious, time-limited use of acetaminophen during pregnancy under medical supervision; updated clinical guidelines to better balance the benefits and risks; and further research to confirm these findings and identify safer alternatives for managing pain and fever in expectant mothers.
“Pregnant women should not stop taking medication without consulting their doctors,” Dr. Prada emphasized. “Untreated pain or fever can also harm the baby. Our study highlights the importance of discussing the safest approach with health care providers and considering non-drug options whenever possible.”
With diagnoses of autism and ADHD increasing worldwide, these findings have significant implications for public health policy, clinical guidelines, and patient education. The study also highlights the urgent need for pharmaceutical innovation to provide safer alternatives for pregnant women.
The study was conducted in collaboration with the University of California, Los Angeles; University of Massachusetts Lowell; and Harvard T.H. Chan School of Public Health.
Read the full study: https://ehjournal.biomedcentral.com/articles/10.1186/s12940-025-01208-0
Funding for this study was provided by the National Cancer Institute (U54CA267776), the National Institute of Environmental Health Sciences (R35ES031688), and the National Institute on Aging (U01AG088684).
###
About the Icahn School of Medicine at Mount Sinai
The Icahn School of Medicine at Mount Sinai is internationally renowned for its outstanding research, educational, and clinical care programs. It is the sole academic partner for the seven member hospitals* of the Mount Sinai Health System, one of the largest academic health systems in the United States, providing care to New York City’s large and diverse patient population.
The Icahn School of Medicine at Mount Sinai offers highly competitive MD, PhD, MD-PhD, and master’s degree programs, with enrollment of more than 1,200 students. It has the largest graduate medical education program in the country, with more than 2,600 clinical residents and fellows training throughout the Health System. Its Graduate School of Biomedical Sciences offers 13 degree-granting programs, conducts innovative basic and translational research, and trains more than 560 postdoctoral research fellows.
Ranked 11th nationwide in National Institutes of Health (NIH) funding, the Icahn School of Medicine at Mount Sinai is among the 99th percentile in research dollars per investigator according to the Association of American Medical Colleges. More than 4,500 scientists, educators, and clinicians work within and across dozens of academic departments and multidisciplinary institutes with an emphasis on translational research and therapeutics. Through Mount Sinai Innovation Partners (MSIP), the Health System facilitates the real-world application and commercialization of medical breakthroughs made at Mount Sinai.
-------------------------------------------------------
* Mount Sinai Health System member hospitals: The Mount Sinai Hospital; Mount Sinai Brooklyn; Mount Sinai Morningside; Mount Sinai Queens; Mount Sinai South Nassau; Mount Sinai West; and New York Eye and Ear Infirmary of Mount Sinai.
Method of Research
Data/statistical analysis
Subject of Research
Not applicable
Article Title
Evaluation of the evidence on acetaminophen use and neurodevelopmental disorders using the Navigation Guide methodology
Article Publication Date
13-Aug-2025