title: Re-starting smoking in the postpartum period after receiving a smoking cessation intervention: a systematic review.
abstract: In pregnant smoking cessation trial participants, to estimate (1) among women abstinent at the end of pregnancy, the proportion who re-start smoking at time-points afterwards (primary analysis) and (2) among all trial participants, the proportion smoking at the end of pregnancy and at selected time-points during the postpartum period (secondary analysis).
  
  
  
  Trials identified from two Cochrane reviews plus searches of Medline and EMBASE. Twenty-seven trials were included. The included trials were randomized or quasi-randomized trials of within-pregnancy cessation interventions given to smokers who reported abstinence both at end of pregnancy and at one or more defined time-points after birth. Outcomes were validated biochemically and self-reported continuous abstinence from smoking and 7-day point prevalence abstinence. The primary random-effects meta-analysis used longitudinal data to estimate mean pooled proportions of re-starting smoking; a secondary analysis used cross-sectional data to estimate the mean proportions smoking at different postpartum time-points. Subgroup analyses were performed on biochemically validated abstinence.
  
  
  
  The pooled mean proportion re-starting at 6 months postpartum was 43% [95% confidence interval (CI) = 16-72%, I(2)  = 96.7%] (11 trials, 571 abstinent women). The pooled mean proportion smoking at the end of pregnancy was 87% (95% CI = 84-90%, I(2)  = 93.2%) and 94% (95% CI = 92-96%, I(2)  = 88%) at 6 months postpartum (23 trials, 9262 trial participants). Findings were similar when using biochemically validated abstinence.
  
  
  
  In clinical trials of smoking cessation interventions during pregnancy only 13% are abstinent at term. Of these, 43% re-start by 6 months postpartum.
authors.affiliation: Division of Primary Care, University of Nottingham, Nottingham, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Jones
authors.affiliation: Division of Epidemiology and Public Health, University of Nottingham, Nottingham, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Lewis
authors.affiliation: Department of Health Sciences, University of York, York, UK.
authors.forename: Steve
authors.initials: S
authors.lastname: Parrott
authors.affiliation: Division of Primary Care, University of Nottingham, Nottingham, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Wormall
authors.affiliation: Division of Primary Care, University of Nottingham, Nottingham, UK.
authors.forename: Tim
authors.initials: T
authors.lastname: Coleman
mesh_terms: D005260:Female; D006801:Humans; D049590:Postpartum Period; D011247:Pregnancy; D011248:Pregnancy Complications / Q000628:therapy*; D012008:Recurrence; D012907:Smoking / Q000628:therapy; D016540:Smoking Cessation; D000073869:Tobacco Smoking / Q000628:therapy*
keywords: Meta-analysis; postpartum period; pregnancy; randomized controlled trial; re-starting smoking; smoking; smoking cessation; smoking cessation interventions; systematic review; tobacco