title: The SNAP trial: a randomised placebo-controlled trial of nicotine replacement therapy in pregnancy--clinical effectiveness and safety until 2 years after delivery, with economic evaluation.
abstract: BACKGROUND
  Smoking during pregnancy causes many adverse pregnancy and birth outcomes. Nicotine replacement therapy (NRT) is effective for cessation outside pregnancy but efficacy and safety in pregnancy are unknown. We hypothesised that NRT would increase smoking cessation in pregnancy without adversely affecting infants.
  
  
  OBJECTIVE
  To compare (1) at delivery, the clinical effectiveness and cost-effectiveness for achieving biochemically validated smoking cessation of NRT patches with placebo patches in pregnancy and (2) in infants at 2 years of age, the effects of maternal NRT patch use with placebo patch use in pregnancy on behaviour, development and disability.
  
  
  METHODS
  Randomised, placebo-controlled, parallel-group trial and economic evaluation with follow-up at 4 weeks after randomisation, delivery and until infants were 2 years old. Randomisation was stratified by centre and a computer-generated sequence was used to allocate participants using a 1 : 1 ratio. Participants, site pharmacies and all study staff were blind to treatment allocation.
  
  
  METHODS
  Seven antenatal hospitals in the Midlands and north-west England.
  
  
  METHODS
  Women between 12 and 24 weeks' gestation who smoked ≥ 10 cigarettes a day before and ≥ 5 during pregnancy, with an exhaled carbon monoxide (CO) reading of ≥ 8 parts per million (p.p.m.).
  
  
  METHODS
  NRT patches (15 mg per 16 hours) or matched placebo as an 8-week course issued in two equal batches. A second batch was dispensed at 4 weeks to those abstinent from smoking.
  
  
  METHODS
  
  
  
  METHODS
  self-reported, prolonged abstinence from smoking between a quit date and childbirth, validated at delivery by CO measurement and/or salivary cotinine (COT) (primary outcome). Infants, at 2 years: absence of impairment, defined as no disability or problems with behaviour and development. Economic: cost per 'quitter'.
  
  
  RESULTS
  One thousand and fifty women enrolled (521 NRT, 529 placebo). There were 1010 live singleton births and 12 participants had live twins, while there were 14 fetal deaths and no birth data for 14 participants. Numbers of adverse pregnancy and birth outcomes were similar in trial groups, except for a greater number of caesarean deliveries in the NRT group. Smoking: all participants were included in the intention-to-treat (ITT) analyses; those lost to follow-up (7% for primary outcome) were assumed to be smoking. At 1 month after randomisation, the validated cessation rate was higher in the NRT group {21.3% vs. 11.7%, odds ratio [OR], [95% confidence interval (CI)] for cessation with NRT, 2.05 [1.46 to 2.88]}. At delivery, there was no difference between groups' smoking cessation rates: 9.4% in the NRT and 7.6% in the placebo group [OR (95% CI), 1.26 (0.82 to 1.96)]. Infants: at 2 years, analyses were based on data from 888 out of 1010 (87.9%) singleton infants (including four postnatal infant deaths) [445/503 (88.5%) NRT, 443/507 (87.4%) placebo] and used multiple imputation. In the NRT group, 72.6% (323/445) had no impairment compared with 65.5% (290/443) in placebo (OR 1.40, 95% CI 1.05 to 1.86). The incremental cost-effectiveness ratio for NRT use was £4156 per quitter (£4926 including twins), but there was substantial uncertainty around these estimates.
  
  
  CONCLUSIONS
  Nicotine replacement therapy patches had no enduring, significant effect on smoking in pregnancy; however, 2-year-olds born to women who used NRT were more likely to have survived without any developmental impairment. Further studies should investigate the clinical effectiveness and safety of higher doses of NRT.
  
  
  BACKGROUND
  Current Controlled Trials ISRCTN07249128.
  
  
  BACKGROUND
  This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 54. See the NIHR Journals Library programme website for further project information.
authors.affiliation: Division of Primary Care, University of Nottingham, Nottingham, UK.
authors.forename: Sue
authors.initials: S
authors.lastname: Cooper
authors.affiliation: Division of Epidemiology and Public Health, University of Nottingham, Nottingham, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Lewis
authors.affiliation: Division of Child Health, Obstetrics and Gynaecology, University of Nottingham, Nottingham, UK.
authors.forename: James G
authors.initials: JG
authors.lastname: Thornton
authors.affiliation: Institute for Women's Health, University College London, London, UK.
authors.forename: Neil
authors.initials: N
authors.lastname: Marlow
authors.affiliation: Academic Division of Midwifery, University of Nottingham, Nottingham, UK.
authors.forename: Kim
authors.initials: K
authors.lastname: Watts
authors.affiliation: Division of Epidemiology and Public Health, University of Nottingham, Nottingham, UK.
authors.forename: John
authors.initials: J
authors.lastname: Britton
authors.affiliation: Division of Epidemiology and Public Health, University of Nottingham, Nottingham, UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Grainge
authors.affiliation: Division of Primary Care, University of Nottingham, Nottingham, UK.
authors.forename: Jaspal
authors.initials: J
authors.lastname: Taggar
authors.affiliation: Department of Health Sciences, University of York, York, UK.
authors.forename: Holly
authors.initials: H
authors.lastname: Essex
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: Anne
authors.initials: A
authors.lastname: Dickinson
authors.affiliation: Division of Primary Care, University of Nottingham, Nottingham, UK.
authors.forename: Rachel
authors.initials: R
authors.lastname: Whitemore
authors.affiliation: Division of Primary Care, University of Nottingham, Nottingham, UK.
authors.forename: Tim
authors.initials: T
authors.lastname: Coleman
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D002675:Child, Preschool; D003362:Cost-Benefit Analysis; D004311:Double-Blind Method; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009538:Nicotine / Q000008:administration & dosage* / Q000009:adverse effects / Q000191:economics; D017063:Outcome Assessment, Health Care; D011247:Pregnancy; D011248:Pregnancy Complications / Q000517:prevention & control*; D011256:Pregnancy Outcome / Q000453:epidemiology*; D012907:Smoking / Q000009:adverse effects / Q000191:economics; D016540:Smoking Cessation / Q000191:economics / Q000379:methods* / Q000706:statistics & numerical data; D000074606:Smoking Prevention; D013995:Time; D061485:Tobacco Use Cessation Devices / Q000009:adverse effects / Q000191:economics / Q000706:statistics & numerical data*
chemical_list: D009538:Nicotine