Acetaminophen Use During Pregnancy and Neurodevelopmental Risk: Biological Plausibility

In May of 2025, a Canadian Mother-Child Initiative on Drug Safety in Pregnancy symposium was held during the Canadian National Perinatal Research Meeting in Montréal, Québec. This symposium included a presentation covering the mechanistic evidence on the biological plausibility of acetaminophen use during pregnancy affecting neurodevelopment. Three mechanistic pathways including oxidative stress, changes in placental and brain transporter expression, and alterations in epigenetic regulation were presented. Given that much of the mechanistic evidence comes from animal and in vitro studies, limitations with these models and their relevance to human pregnancy were also considered. Current evidence for both human and mechanistic studies remain too limited and inconsistent to infer a causal effect at typical clinical exposures. Therefore, the Society of Obstetricians and Gynaecologists of Canada's recommendation that "the use of acetaminophen as a first-line therapeutic option for fever and pain in pregnancy when medically indicated at recommended doses for the shortest duration required" is supported.