Prenatal exposure to acetaminophen and respiratory symptoms in the first year of life

Background: Prevalence of asthma in developed countries increased between the 1970s and the 1990s. One factor that might contribute to the trends in asthma is the increased use of acetaminophen vs aspirin in children and pregnant women. Objective: To examine relationships between in utero exposure to acetaminophen and incidence of respirator), symptoms in the first year of life. Methods: A total of 345 women were recruited in the first trimester of pregnancy and followed LIP with their children through the first year of life. Use of acetaminophen in pregnancy was determined by questionnaire and related to incidence of respiratory symptoms. Results: Use of acetaminophen in middle to late but not early pregnancy was significantly related to wheezing (odd ratio, 1.8: 95% confidence interval. 1.1-3.0) and to wheezing that disturbed sleep (odds ratio, 2.1; 95% confidence interval, 1.1-3.8) in the first year of life after control for potential confounders. Conclusion: This study suggests that use of acetaminophen in middle to late but not early pregnancy may be related to respiratory symptoms in the first year of life. Additional follow-up will examine relationships of maternal and earl), childhood use of acetaminophen with incidence of asthma at ages 3 to 5 years, when asthma diagnosis is more firmly established.