Summary: A new study has raised concerns about the safety of acetaminophen use during pregnancy, linking prenatal exposure to higher risks of autism and ADHD. Using the gold-standard Navigation Guide review method, the team analyzed 46 studies with over 100,000 participants, finding that stronger studies more consistently showed a connection.
While the evidence does not prove causation, it highlights biological mechanisms such as oxidative stress and hormone disruption that may affect fetal brain development. Researchers recommend cautious, time-limited use under medical supervision and call for safer treatment alternatives.
Key Facts
- Study Scope: Review covered 46 studies and more than 100,000 participants worldwide.
- Key Finding: Stronger studies more often found links between prenatal acetaminophen and autism/ADHD.
- Health Implications: Results urge caution, medical oversight, and safer alternatives for expectant mothers.
Source: Mount Sinai Hospital
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.
Funding:
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 this Autism and neurodevelopment research news
Author: Mount Sinai Health System Press Office
Source: Mount Sinai Hospital
Contact: Mount Sinai Health System Press Office – Mount Sinai Hospital
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Evaluation of the evidence on acetaminophen use and neurodevelopmental disorders using the Navigation Guide methodology” by Diddier Prada et al. BMC Environmental Health
Abstract
Evaluation of the evidence on acetaminophen use and neurodevelopmental disorders using the Navigation Guide methodology
Background
Acetaminophen is the most commonly used over-the-counter pain and fever medication taken during pregnancy, with > 50% of pregnant women using acetaminophen worldwide.
Numerous well-designed studies have indicated that pregnant mothers exposed to acetaminophen have children diagnosed with neurodevelopmental disorders (NDDs), including autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), at higher rates than children of pregnant mothers who were not exposed to acetaminophen.
Methods
We applied the Navigation Guide methodology to the scientific literature to comprehensively and objectively examine the association between prenatal acetaminophen exposure and NDDs and related symptomology in offspring.
We conducted a systematic PubMed search through February 25, 2025, using predefined inclusion criteria and rated studies based on risk of bias and strength of evidence. Due to substantial heterogeneity, we opted for a qualitative synthesis, consistent with the Navigation Guide’s focus on environmental health evidence.
Results
We identified 46 studies for inclusion in our analysis. Of these, 27 studies reported positive associations (significant links to NDDs), 9 showed null associations (no significant link), and 4 indicated negative associations (protective effects). Higher-quality studies were more likely to show positive associations.
Overall, the majority of the studies reported positive associations of prenatal acetaminophen use with ADHD, ASD, or NDDs in offspring, with risk-of-bias and strength-of-evidence ratings informing the overall synthesis.
Conclusions
Our analyses using the Navigation Guide thus support evidence consistent with an association between acetaminophen exposure during pregnancy and increased incidence of NDDs. Appropriate and immediate steps should be taken to advise pregnant women to limit acetaminophen consumption to protect their offspring’s neurodevelopment.
