Prenatal Exposure to Acetaminophen and Asthma in Children

OBJECTIVE: To estimate whether prenatal exposure to acetaminophen is associated with risk of diagnosed asthma and asthma symptoms in children. METHODS: The authors prospectively followed 1,505 pregnant women and their children until 6 years ( 3 months) of life. Acetaminophen use in the first and third trimesters of pregnancy was assessed before 24 weeks of gestation and within 1 month of delivery, and asthma in children was assessed when the child was 6 years old. Adjusted odds ratios (aORs) were derived from logistic regression models controlling for potential confounders. RESULTS: Acetaminophen was used by 69% of women during pregnancy. Use of acetaminophen did. not significantly increase the risk of asthma (aOR 0.76, 95% confidence interval [CI] 0.53-1.10). Acetaminophen use during both the first and the third trimester was associated with a significantly reduced risk of asthma (aOR 0.59, 95% CI 0.36-0.98). There was no evidence of a dose response, and consumption greater than 10,400 mg (32 tablets) a month did not increase risk (aOR 0.99, 95% CI 0.19-5.30). CONCLUSION: Our results suggest that acetaminophen use during pregnancy does not increase risk of asthma in children. (Obstet Gynecol 2009;114:1295-1306)