title: Maternal smoking and preeclampsia.
abstract: OBJECTIVE
  To study the relationship between maternal smoking and preeclampsia and whether this association differs between primiparous and multiparous women.
  
  
  METHODS
  We conducted a population-based, retrospective, cohort study of 58,216 singleton pregnancies from northern and central Alberta, Canada, between 1995 and 1997. Multivariate logistic regression was used to control for maternal alcohol consumption, drug dependence, maternal age, maternal weight, prior intrauterine growth restriction and other confounders.
  
  
  RESULTS
  Maternal smoking was associated with a significantly reduced overall risk of preeclampsia (adjusted odds ratio [aOR]: .61; 95% confidence interval [CI]: .50-.75; P < .01). Stratified analyses showed that in primiparous pregnancies, maternal smoking was associated with a significantly decreased risk (aOR: .63; 95% CI: .50-.80; P < .01); in multiparous women, maternal smoking was not associated with a statistically significant decreased risk of preeclampsia (aOR: 0.72; 95% CI: .51-1.02; P > .05).
  
  
  CONCLUSIONS
  Maternal smoking is protective against preeclampsia. Understanding the underlying biologic mechanisms of this protective effect may advance our knowledge of the pathogenesis of preeclampsia.
authors.affiliation: Perinatal Research Centre, University of Alberta, and Health Surveillance, Alberta Health and Wellness, Edmonton, Canada. xxiong@gpu.srv.ualberta.ca
authors.forename: X
authors.initials: X
authors.lastname: Xiong
authors.forename: F L
authors.initials: FL
authors.lastname: Wang
authors.forename: S T
authors.initials: ST
authors.lastname: Davidge
authors.forename: N N
authors.initials: NN
authors.lastname: Demianczuk
authors.forename: D C
authors.initials: DC
authors.lastname: Mayes
authors.forename: D M
authors.initials: DM
authors.lastname: Olson
authors.forename: L D
authors.initials: LD
authors.lastname: Saunders
mesh_terms: D000293:Adolescent; D000328:Adult; D000416:Alberta / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D010298:Parity; D011225:Pre-Eclampsia / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking