title: Quitting smoking during early versus late pregnancy: the risk of preeclampsia and adverse birth outcomes.
abstract: OBJECTIVE
  To examine the impact of women's quitting smoking during early and late pregnancy on their risk of preeclampsia and on birth outcomes.
  
  
  METHODS
  We analyzed data from a case-control study of 86 preeclamptic women and 239 controls at three hospitals in Quebec between January 2003 and March 2006.
  
  
  RESULTS
  Compared with never having smoked, early smoking cessation, i.e., quitting before 20 weeks' gestation, was not associated with a reduced risk of preeclampsia (adjusted OR 1.03; 95% CI 0.42-2.60). Both late smoking cessation (quitting after 20 weeks of gestation) and persistent smoking (smoking before and during pregnancy) were associated with a non-significant reduction in the risk of preeclampsia (aOR 0.78; 95% CI 0.12-5.02 for late quitting and aOR 0.62; 95% CI 0.16-2.37 for persistent smoking). However, persistent smoking was associated with an increased risk of other adverse pregnancy outcomes, such as low birth weight (aOR 10.2; 95% CI 2.49-41.8) and preterm birth (aOR 3.59; 95% CI 1.06-12.1).
  
  
  CONCLUSIONS
  Although late quitting and persistent smoking may be associated with a decreased risk of preeclampsia, the benefit of early smoking cessation on pregnancy outcome is evident.
authors.affiliation: Department of Epidemiology, Tulane University, New Orleans LA.
authors.forename: Xu
authors.initials: X
authors.lastname: Xiong
authors.affiliation: National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Obstetrics and Gynecology, University of Montreal, Montreal QC.
authors.forename: William D
authors.initials: WD
authors.lastname: Fraser
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D011225:Pre-Eclampsia / Q000453:epidemiology* / Q000517:prevention & control*; D011247:Pregnancy; D011256:Pregnancy Outcome; D016540:Smoking Cessation; D055815:Young Adult