The question of whether **Tylenol (acetaminophen) use during pregnancy is connected to autism spectrum disorder (ASD)** has been the subject of extensive research and public discussion. Current scientific evidence shows **no proven causal link** between acetaminophen use in pregnancy and autism, although some studies have observed a possible association or slight increase in risk. This distinction between association and causation is critical in interpreting the data.
Acetaminophen is widely used as a pain reliever and fever reducer during pregnancy because it is considered safer than alternatives like aspirin or ibuprofen, which have known risks for the fetus. Over the past few decades, researchers have investigated whether acetaminophen exposure in utero might influence neurodevelopmental outcomes, including ASD and attention-deficit/hyperactivity disorder (ADHD).
A comprehensive review published in 2025 analyzed 46 studies on acetaminophen use during pregnancy and neurodevelopmental outcomes. Slightly more than half of these studies found a minimal association with increased risk of autism or ADHD, while others found no evidence of increased risk at all. Importantly, none of these studies established a direct cause-and-effect relationship. The observed associations could be influenced by confounding factors such as the underlying illness that prompted acetaminophen use, genetic predispositions, or other environmental exposures[1].
The U.S. Food and Drug Administration (FDA) has acknowledged this body of evidence and initiated a process to update acetaminophen labeling to reflect the potential association with neurological conditions like autism and ADHD. However, the FDA emphasizes that this is an association, not proof of causation, and that acetaminophen remains the only over-the-counter medication approved for fever reduction during pregnancy. High fevers themselves pose risks to fetal development, and alternatives like aspirin and ibuprofen carry known fetal risks, making acetaminophen the preferred option in many cases[2].
Experts such as Dr. Zeyan Liew from Yale School of Public Health, who has conducted extensive research on this topic, confirm that while some large observational studies report associations between frequent or prolonged acetaminophen use during pregnancy and neurodevelopmental disorders, these findings are not conclusive. Other factors may contribute to autism risk, and more definitive research is needed. Until then, public health authorities including the FDA and CDC continue to recommend acetaminophen as the safest over-the-counter pain reliever for pregnant women[3].
The World Health Organization (WHO) also states that there is currently no conclusive scientific evidence confirming a link between acetaminophen use during pregnancy and autism[4].
In summary, the current scientific consensus is that while some studies suggest a possible association between prenatal acetaminophen exposure and autism, **there is no definitive proof that acetaminophen causes autism**. Pregnant women should consult their healthcare providers to weigh the benefits and risks of acetaminophen use, especially considering the risks of untreated fever or pain during pregnancy.
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**Sources:**
[1] Autism Science Foundation, “Acetaminophen During Pregnancy: What the Research Really Says About Autism Risk,” updated Sept. 23, 2025.
[2] U.S. Food and Drug Administration, “FDA Responds to Evidence of Possible Association Between Autism and Acetaminophen Use During Pregnancy,” Sept. 2025.
[3] Yale School of Public Health, Interview with Dr. Zeyan Liew,
