Amid growing concern over neurodevelopmental disorders, a recent study from Mount Sinai Hospital has reignited the debate surrounding acetaminophen, commonly known as paracetamol or Tylenol.
This analgesic, used by over 50% of pregnant women worldwide to relieve pain and fever, maybe linked to an increased risk of autism and attention deficit hyperactivity disorder (ADHD) in their children.
The report, published in August 2025 in the journal Environmental Health, analyzed 46 previous studies from international groups.
It applied the Navigation Guide methodology, a rigorous framework for evaluating environmental evidence. The findings show a consistent association: prenatal acetaminophen exposure increases the risk of autism by 19% (odds ratio 1.19) and ADHD by 26% (odds ratio 1.26).
Diddier Prada, MD, PhD, lead researcher at the Icahn School of Medicine at Mount Sinai, emphasized: “Our findings indicate that higher-quality studies are more likely to show a link between prenatal acetaminophen exposure and elevated risks of autism and ADHD.”
The analysis included 20 studies on ADHD, eight on autism, and 18 on other neurodevelopmental disorders. This is not an isolated finding. A 2019 Johns Hopkins study, based on umbilical cord blood samples from 996 children, found that high acetaminophen levels tripled the risk of autism (up to 3.62 times) and doubled the risk of ADHD (up to 2.86 times).
Researchers measured metabolites in blood at birth and followed the children for an average of 8.9 years. Another study, funded by the NIH in 2025, confirmed similar patterns: the middle third of exposure increased the risk of ADHD by 2.26 times and autism by 2.14 times.
These data come from cohorts such as the Boston Birth Cohort and the Nurses’ Health Study II. The underlying biology points to concerning mechanisms. Acetaminophen crosses the placental barrier and can induce oxidative stress, disrupt hormones, and cause epigenetic changes that interfere with fetal brain development. The risk appears heightened in the third trimester, when the brain develops rapidly.
In September 2025, the U.S. FDA responded with a letter to clinicians, initiating changes to product labels like Tylenol’s. It cited “accumulated evidence” of an association with autism and ADHD, recommending minimal doses and short-term use.
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