Methods	3-armed cluster-randomised trial of self-help manuals and computer-generated advice to support women to stop smoking in pregnancy Study conducted in community midwife clinics in the West Midlands region of the UK, with data collection from July 1998 to March 2001
Participants	Inclusion criteria: Head midwife in every trust in region invited to participate and 16/19 agreed to participate. 204 potential midwifery practices identified, and 103 excluded by head midwife as those trusts were already involved in other regions or the practice crossed trust boundaries. Women were eligible if aged 16 years or over and a ‘current smoker’ at booking Exclusion criteria: Women not fluent in English. Recruitment: 72/101 practices were randomly sampled (C = 24, I1 = 24, I2 = 23). Further practices were later added to each arm due to slow recruitment, particularly in the control arm (C = 17, I1 = 12, I2 = 0), leaving active practices (C = 32, I1 = 30, I2 = 22). Participating midwives were asked to recruit all eligible women seen in routine antenatal appointments. Initial target of 1440 participants was reduced to 900 due to slow recruitment. Eligible smokers approached: C = 328/965 (34%),I1 (manuals) = 327/694 (47%), I2 (computer) = 397/529 (75%). Participation rate: C = 289/328 (88%), I1 = 305/327 (93%),I2 = 324/397 (82%). Baseline characteristics:Mean cigarettes per day at baseline were similar between groups (reported in 6 smoking categories). Majority (over 60%) smoked 5-20 cigarettes per day and over 50% had a partner who smoked. Median fagerstrom score 3 in all arms 63.6% of participants on < $300/week. Progress+ coding: Low SES.
Interventions	Control: Standard care. Midwives received a half-day training on research protocol, and asked all midwives to give women the Health Education Authority booklet “Thinking about stopping” Intervention 1 (self-help booklets): Midwives received 2 and a half days training on theory of transtheoretical model. Participants received a set of 6 stage-based self-help manuals “Pro-Change programme for a healthy pregnancy”. The midwife assessed each participant’s stage of change and pointed the woman to the appropriate manual. No more than 15 minutes was spent on the intervention Intervention 2 (self-help booklets+computerised advice):Midwives received the same training as for I1, and participants received the same self-help manual and intervention as I1. Additionally, the participants used a computer programme, which consisted of questions and auto feedback of what stage they were in and what this meant, and a range of other concepts. It took about 20 minutes for the woman to complete. Printed information of the feedback was sent to the participant within a week of the intervention Main intervention strategy: Counselling (multiple intervention) compared with usual care. Intervention 2 were combined and compared with the control arm in this review Intensity: Frequency (C = 0, I = 3); Duration (C = 0, I = 3). Usual care intensity: F = 1, D = 1 Intervention provided by existing staff (Midwives providing self-help manuals): effectiveness study
Outcomes	Biochemically validated point prevalence abstinence at 28-30 weeks’ gestation (late pregnancy)* (T3) and 10 days post-birth* (T4) (0-5 months postpartum). Effect of midwife training (attitudes, expectations, confidence, concerns and routine practice) was assessed by pre-post training questionnaires Subsequent papers (Lawrence 2005b) measure and describe self-reported smoking cessation at 18 months postpartum, movement in stage of change, partner quitting, social support mobilisation, and the stress of receiving the intervention
Notes	Intracluster correlation of 0.003 reported and used for adjusting outcome data included in this meta-analysis (see Table 2). Sample size calculation given, but unable to recruit sufficient numbers
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A computerised minimisation programme was used to stratify 72 eligible practices into 3 equal groups from101 available practices
Allocation concealment (selection bias)	High risk	Further practices were added to the sample because of slow recruitment - these were not randomly allocated
Incomplete outcome data (attrition bias) All outcomes	Low risk	Different rates of recruitment and followup in different arms of the trial. 272 (C= 1 04, I1 = 86, I2 = 82) women (22.5%) withdrew from the study or were lost to follow-up. Data on smoking status were only available for 67% of women. Where there was no urine sample available women were treated as continuing smokers. All randomised participants were included in the denominator in this analysis, with only those reported as confirmed non-smokers at T4 included as quitters
Selective reporting (reporting bias)	Unclear risk	Not apparent.
Other bias	High risk	Slow recruitment to standard care arm, so additional practices needed to be added
Biochemical validation of smoking abstinence (detection bias)	Low risk	Urinary cotinine analysis (< 1.5 ug/L).
Blinding of participants and personnel (performance bias) All outcomes	High risk	Neither providers nor women blinded to this educational intervention
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported
Incomplete implementation	Low risk	77% T4 questionnaires complete in I2.
Equal baseline characteristics in study arms	Low risk	There was little difference at recruitment between the midwives or recruited women in the 3 trial arms
Contamination of control group	Low risk	Cluster design to reduce risk of contamination.