title: Maternal asthma and risk of preterm delivery.
abstract: OBJECTIVE
  We studied the relation between maternal history of asthma and preterm delivery.
  
  
  METHODS
  The 312 preterm delivery cases, studied in aggregate, and in subgroups (spontaneous preterm labor, preterm premature rupture of membranes, medically induced preterm delivery), were compared with 424 randomly selected women who delivered at term. Maternal medical records provided information on maternal lifetime asthma status, pregnancy outcome, and sociodemographic characteristics. Using multivariate logistic regression, we derived maximum likelihood estimates of adjusted odds ratios (OR) and 95% confidence intervals (CI).
  
  
  RESULTS
  Maternal history of asthma was associated with an increased risk of preterm delivery overall (OR = 2.37; 95% CI 1.15-4.88). Analyses of preterm delivery sub-groups indicated that maternal history of asthma was associated with at least a doubling in risk of spontaneous preterm labor (OR = 2.35; 95% CI 0.84-6.58) and medically induced preterm delivery (OR = 2.69; 95% CI 1.11-6.53), though only the latter approached statistical significance. There was some evidence of a modest association between maternal asthma and risk of preterm premature rupture of membranes (OR = 1.63; 95% CI 0.50-5.33).
  
  
  CONCLUSIONS
  These results support the hypothesis that maternal asthma is associated with an increased risk of preterm labor and delivery.
authors.affiliation: Center for Perinatal Studies, Swedish Medical Center, Seattle, WA 98122, USA.
authors.forename: Tanya K
authors.initials: TK
authors.lastname: Sorensen
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Dempsey
authors.forename: Rong
authors.initials: R
authors.lastname: Xiao
authors.forename: Ihunnaya O
authors.initials: IO
authors.lastname: Frederick
authors.forename: David A
authors.initials: DA
authors.lastname: Luthy
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Williams
mesh_terms: D000328:Adult; D001249:Asthma / Q000453:epidemiology*; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000453:epidemiology*; D006801:Humans; D016013:Likelihood Functions; D016015:Logistic Models; D007752:Obstetric Labor, Premature / Q000453:epidemiology*; D016017:Odds Ratio; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D012307:Risk Factors