While acetaminophen is considered the only safe over-the-counter pain reliever for pregnancy, new research suggests it may result in speech delays in children.
Recommended by both the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine, acetaminophen is the only over-the-counter pain reliever considered safe during pregnancy. However, new research suggests that taking the drug during the second or third trimester may result in language delays in young children.
Researchers at the University of Illinois Urbana-Champaign analyzed the relationship between taking acetaminophen while pregnant and language development in children, finding that taking more acetaminophen during the second or third trimester was associated with marginally smaller vocabularies and shorter utterance length at 26.5–28.5 months of age.
They discovered that more acetaminophen use during the third trimester was also associated with increased odds of utterance length in the 25th percentile or lower in male children, and more use during the second or third trimester was associated with lower scores on the Speech and Language Assessment Scale (SLAS) at 36–38 months. Third trimester use was specifically related to lower SLAS scores in male children, according to the study.
"Recent studies suggest that use during pregnancy may be associated with poorer neurodevelopmental outcomes in children, but few have examined language development," the study authors wrote. "This study adds to the growing body of literature suggesting that the potential impact of acetaminophen use during pregnancy on fetal neurodevelopment should be carefully evaluated."
The findings are particularly relevant considering the prevalence of acetaminophen use during pregnancy, with 50–65% of pregnant women in North America and Europe reporting the use of acetaminophen, or a medication containing it, at least once while pregnant.
Early language development is meanwhile predictive of later IQ, reading ability, and school success, according to the study.
A lack of clinical trials in pregnant women and very few reported cases of adverse effects in the developing child have resulted in little insight into the actual safety of acetaminophen use during pregnancy despite its reputation as "safe." But research shows that acetaminophen can cross the placenta, and there has been increased interest in examining whether acetaminophen use during pregnancy could be related to child health outcomes.
"The idea that [acetaminophen] is safe for use has been taken for granted for many years without any demonstration of its safety regarding neurodevelopment," the authors wrote. "This study provides additional evidence that more acetaminophen use during pregnancy is related to poorer language development and highlights the need for further investigation of the potential mechanisms through which prenatal acetaminophen exposure may impact neurodevelopment."
The research was conducted as a part of the Illinois Kids Development Study, a prospective birth cohort in east-central Illinois in which 532 newborns were enrolled between December 2013 and March 2020. Participants reported the number of times they took acetaminophen throughout pregnancy, and language data were collected from their offspring at 26.5–28.5 months using the MacArthur-Bates Communicative Development Inventories and at 36–38 months using the Speech and Language Assessment Scale.
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