For decades, Tylenol has been one of the most common over-the-counter medications used to reduce pain and fever. It is also often recommended during pregnancy since alternatives like ibuprofen are generally avoided in later trimesters. However, in recent years, researchers, parents, and administrations have raised questions about whether taking this medication during pregnancy may be linked to developing conditions like autism spectrum disorder.
Early studies in the 2010s and 2020s started noticing small but consistent associations between prenatal Tylenol usage (brand name for acetaminophen) and neurodevelopmental outcomes in newborns. Specifically, large observational studies in Europe and the United States found that children exposed to Tylenol in the womb were slightly more likely to be diagnosed with autism later in life.
Scientists have proposed different reasons for how this causation occurs in the body, one of them being that high doses of Tylenol can affect the body’s ability to handle oxidative stress, which can potentially influence neural cells. Another mechanism that has been explored is that Tylenol may interfere with hormones involved in brain development.
While the findings may appear concerning, researchers caution that the evidence does not actually prove that Tylenol causes autism. One of the challenges for this notion is that pregnant women may take tylenol for fevers, infections, or pain; these conditions themselves could incidentally also affect fetal development, posing an issue in determining whether the medication or illness was the driver.
As Professor Fredricks from the Psychology department indicates, “Some studies do find a correlation, but findings are mixed and likely can be explained by confounding variables, such as health conditions or infections.” Also, most studies rely on parents recalling what medications they took during pregnancy, which can be imprecise.
While the research has raised important questions about the relationship between prenatal Tylenol use and autism, current evidence does not confirm a direct cause-and-effect link. Many studies highlight small associations but also acknowledge limitations such as underlying health conditions and other confounding variables. Hence, continued research is essential to confirm how and when Tylenol may influence fetal development, but until there is clearer evidence, informed decision-making remains the best approach.
