title: Paracetamol use in pregnancy and wheezing in early childhood.
abstract: 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 exposure 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 paracetamol 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=9,400) 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); p=0.008). Assuming a causal relation, only about 1% of wheezing at 30-42 months was attributable to this exposure. Frequent paracetamol use in pregnancy was not associated with an increased risk of eczema. Frequent aspirin use in pregnancy was associated with an increased risk of wheezing only at <6 months.
  
  
  CONCLUSIONS
  Frequent use of paracetamol in late pregnancy may increase the risk of wheezing in the offspring, although such an effect could explain only about 1% of the population prevalence of wheezing in early childhood.
authors.affiliation: Department of Public Health Sciences, Guy's, King's and St Thomas' School of Medicine, King's College, London, SE1 3QD, UK. seif.shaheen@kcl.ac.uk
authors.forename: S O
authors.initials: SO
authors.lastname: Shaheen
authors.forename: R B
authors.initials: RB
authors.lastname: Newson
authors.forename: A
authors.initials: A
authors.lastname: Sherriff
authors.forename: A J
authors.initials: AJ
authors.lastname: Henderson
authors.forename: J E
authors.initials: JE
authors.lastname: Heron
authors.forename: P G J
authors.initials: PG
authors.lastname: Burney
authors.forename: J
authors.initials: J
authors.lastname: Golding
mesh_terms: D000082:Acetaminophen / Q000009:adverse effects*; D018712:Analgesics, Non-Narcotic / Q000009:adverse effects*; D001241:Aspirin / Q000009:adverse effects; D001249:Asthma / Q000209:etiology*; D004485:Eczema / Q000209:etiology; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D016017:Odds Ratio; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy*; D012135:Respiratory Sounds / Q000209:etiology*
chemical_list: D018712:Analgesics, Non-Narcotic; D000082:Acetaminophen; D001241:Aspirin