A mounting body of evidence shows that the use of acetaminophen – widely known by its brand name Tylenol – during pregnancy may pose risks to the fetus and to early childhood development. That was the conclusion of a new review study on which I was a lead author.
Acetaminophen, which has the chemical name paracetamol, is a go-to over-the-counter medication that is widely recommended by doctors to relieve pain and reduce fever.
Our study, based on an assessment of 25 years of research in the areas of human epidemiology, animal and in-vitro studies, concludes that prenatal acetaminophen exposure may increase the risks of reproductive organs developing improperly. We identified a heightened risk of neurodevelopmental disorders, primarily attention deficit hyperactivity disorder and related behaviors, but also autism spectrum disorder, as well as language delays and decreased IQ.
In our consensus statement – a broad agreement by our multidisciplinary international panel of experts – published in Nature Reviews Endocrinology in September 2021, 91 clinicians and researchers are calling for caution and additional research.
Why it matters
Acetaminophen is an active ingredient in over 600 prescription and over-the-counter medications. It is used by more than 50% of pregnant women worldwide and at least 65% of pregnant women in the U.S. Research suggests that acetaminophen is an endocrine disruptor and may interfere with the hormones essential for healthy neurological and reproductive development.
Current guidance recommends acetaminophen as the pain reliever of choice during pregnancy, as other pain relievers such as ibuprofen and aspirin are not considered safe after midpregnancy.
Rates of reproductive disorders and neurodevelopmental disorders, such as ADHD and autism spectrum disorder, have been increasing over the last 40 years.
Over the same time period, the use of acetaminophen during pregnancy has gone up. We conclude that because acetaminophen is so commonly taken during pregnancy, if its use is responsible for even a small increase in individual risk, it could contribute substantially to these disorders in the overall population.