ORIGINAL ARTICLE Paracetamol use in pregnancy and wheezing in early

Background: We recently reported links between frequent paracetamol (acetaminophen) use and wheezing and asthma in adults and children, but data are lacking on possible effects of prenatal expo-sure on wheezing in early childhood. Methods: In the population based Avon Longitudinal Study of Parents and Children (ALSPAC) women were asked twice during pregnancy (at 18–20 weeks and 32 weeks) about their usage of paraceta-mol and aspirin. Six months after birth, and at yearly intervals thereafter, mothers were asked about wheezing and eczema symptoms in their child. The effects of paracetamol and aspirin use in pregnancy on the risk in the offspring of wheezing at 30–42 months (n=9400) and eczema at 18–30 months (n=10 216) and on their risk of different wheezing patterns (defined by presence or absence of wheezing at <6 months and at 30–42 months) were examined. Results: Paracetamol was taken frequently (most days/daily) by only 1 % of women. After controlling for potential confounders, frequent paracetamol use in late pregnancy (20–32 weeks), but not in early pregnancy (<18–20 weeks), was associated with an increased risk of wheezing in the offspring at 30–42 months (adjusted odds ratio (OR) compared with no use 2.10 (95 % CI 1.30 to 3.41); p=0.003), particularly if wheezing started before 6 months (OR 2.34 (95 % CI 1.24 to 4.40)