Mount Sinai study supports evidence that prenatal acetaminophen use may be linked to increased risk of autism and ADHD

[Wicked Blue]

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.

-snip-

“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.

https://www.eurekalert.org/news-releases/1094641

[Lionel Mandrake]

1. Association does not imply causation.

Suppose in a study of Ntotal random births, it is found that
N(A) offspring are autistic;
N(T) mothers took Tylenol (aka acetaminophen or paracetamol); and
N(AT) mothers tookTylenol AND had autistic kids.
There is a link, or association, if
N(AT)/Ntotal >> (N(A)/Ntotal ) (N(T)/Ntotal ),
where >> means significantly greater than.
Some studies have shown such a link, but this is not evidence of causation. It is known that a pregnant woman's fever can cause autism and other problems. The association between autism and Tylenol should not come as a big surprise, because when a pregnant woman has a fever she is very likely to take Tylenol.

[quaint]

2. "Our findings show that higher-quality studies are more likely..."

This is just enough for me to keep an open mind awaiting higher-quality studies.