Prenatal over-the-counter acetaminophen use and birth outcomes in the ECHO Cohort

Acetaminophen is among the most common over-the-counter medications used during pregnancy. Given inconsistent findings from both experimental and epidemiological studies on associations between use and adverse health outcomes, further research is warranted. To address this, our objective was to assess the relationship between prenatal acetaminophen use and birth outcomes. We studied 8957 mother-infant pairs from 36 pediatric study sites participating in the Environmental influences on Child Health Outcomes (ECHO) program. After imputation and inverse probability weighting, we used regression models to examine the relationship between acetaminophen during pregnancy and the following outcomes: (1) preterm birth, (2) birthweight, (3) small-for-gestational age (SGA), and (4) large-for-gestational-age (LGA). Approximately 59% of mothers reported using acetaminophen at any point during their pregnancy (n = 5257). After adjustment for relevant covariates, prenatal acetaminophen use was associated with lower odds of LGA (adjusted odds ratio [aOR]: 0.87; 95% CI: 0.79, 0.96). Prenatal acetaminophen use was not associated with preterm birth (aOR: 0.99; 95% CI: 0.86, 1.14), birthweight (aβ: -7.52 g; 95% CI: -27.80, 12.77) or SGA (aOR: 1.02; 95% CI: 0.88, 1.18). Based on these findings, future research should test for dose-response, trimester-specific exposures, and factors affecting individual responses.