title: Smoking behaviour in pregnancy and its impact on smoking cessation at various intervals during follow-up over 21 years: a prospective cohort study.
abstract: OBJECTIVE
  To determine whether mothers who quit or reduce their level of smoking in pregnancy comprise a group of health-conscious women who are disproportionally likely to adopt a healthier smoking lifestyle in the medium to longer term, compared with women who continue to smoke during pregnancy.
  
  
  METHODS
  A prospective cohort study.
  
  
  METHODS
  A public hospital in Australia.
  
  
  METHODS
  A cohort of 6703 individual mothers who completed both initial phases of data collection in 1981-1983; mothers who smoked daily (2992) before pregnancy were included in this study.
  
  
  METHODS
  Mothers were interviewed at 3-5 days post-delivery, 6 months, 5 years, 14 years and 21 years to determine their smoking status. An inverse probability-weighted Poisson regression with a robust error variance was fitted to the data using a log-link function and a binary response variable for smoking outcome, and adjusting for several possible confounding factors.
  
  
  METHODS
  Smoking cessation at several follow-up points, for up to 21 years.
  
  
  RESULTS
  Of the mothers who smoked daily before pregnancy, 12, 23, 37 and 41% reported having ceased smoking at 6 months and at 5, 14 and 21 years, respectively. The decision to quit smoking during pregnancy was found to be independently associated with a higher rate ratio (RR) of smoking cessation at 6 months (RR 30.60, 95% CI 20.50-45.69), 5 years (RR 4.36; 95% CI 3.61-5.27), 14 years (RR 2.42, 95% CI 2.12-2.75) and 21 years (RR 1.86; 95% CI 1.60-2.15), after adjusting for several possible confounding factors.
  
  
  CONCLUSIONS
  Pregnancy appears to be an opportunity for successfully quitting smoking, regardless of socio-economic circumstances or demographic background.
authors.affiliation: School of Population Health, University of Queensland, Brisbane, QLD, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Rattan
authors.forename: A
authors.initials: A
authors.lastname: Mamun
authors.forename: J M
authors.initials: JM
authors.lastname: Najman
authors.forename: G M
authors.initials: GM
authors.lastname: Williams
authors.forename: S A
authors.initials: SA
authors.lastname: Doi
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D049590:Postpartum Period / Q000523:psychology; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000523:psychology*; D016540:Smoking Cessation / Q000523:psychology*; D055815:Young Adult