Several observational studies published between 2018 and 2023 found statistical associations between prolonged prenatal acetaminophen use (typically daily use for weeks) and a small increase in the risk of ADHD, autism spectrum traits, and reproductive effects in offspring.
These studies have important limitations. They rely on self-reported medication use (which is unreliable), they cannot separate the effect of the drug from the effect of the underlying condition being treated (pain, fever, and infection themselves can affect development), and the effect sizes are small. No randomized controlled trial has ever been conducted to test this question directly, for obvious ethical reasons.
ACOG's position is clear: "Patients should not be alarmed by potential associations reported in observational studies, particularly when the data are inconsistent and the findings may be confounded by the conditions for which acetaminophen was taken."
For a complete reference on all medications during pregnancy, see our pregnancy-safe medications guide.