Methods	Pilot randomised controlled trial to evaluate the feasibility, acceptability and potential effectiveness of tailored leaflets and SMS text messaging self-help intervention (MiQuit) to support women to stop smoking in pregnancy Study conducted in 7 National Health Service Trusts in the south east, east and north east of England (UK), with recruitment between December 2008 and October 2009
Participants	Inclusion criteria: Pregnant women less than 21 weeks’ gestation, 16 years of age and over, smoked >= 7 cigarettes per week, owned or had regular use of a mobile phone, and could understand written English Exclusion criteria: Not further specified. Recruitment: 625 women were referred by midwives to the study and 207/512 (40%) eligible women agreed to participate and were randomised to the study (C = 105, I = 102) Baseline characteristics: Cigarettes per day before pregnancy and at enrolment reported by 6 categories and equal in both arms. Majority (over 60%) 11-20 cigs/day before pregnancy and approx 50% 4-10 cigarettes/day at enrolment Median age 26-27 years; 16% did not complete high school; 100% white Progress+ coding: None.
Interventions	Control: Participants received a non-tailored self-help leaflet, which matched the tailored leaflet in format and style, and the same assessment texts as MiQuit participants but no intervention texts Intervention: Participants receive MiQuit tailored self-help leaflet by post. Thereafter automated tailored text message component of intervention is initiated. 80 texts sent out over 11 weeks. MiQuit participants could also request instant response supportive texts at any time of the day Main intervention strategy: Health education (multiple intervention) compared to less intensive intervention Intensity: Frequency: (C = 2, I = 5), Duration: (C = 1, I = 1). Technological intervention: Unclear whether efficacy or effectiveness study
Outcomes	Biochemically validated 7-day point prevalence at 3-month follow-up (late pregnancy)*, self-reported 4-week point prevalence, initiation and frequency of quit attempts and 7-day point prevalence at 3 and 7 weeks after enrolment; Self-efficacy (5-point scale), acceptability measures
Notes	Process evaluation showed 98% intervention and 89% control participants received the leaflet and 87% intervention participants reported reading text messages at least once
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Generation of the randomisation tables and allocation of participants were implemented in a computer programme and managed by SS who had no contact with participants or involvement in data collection or entry
Allocation concealment (selection bias)	Low risk	‘The allocation sequence was concealed from other members of the research team, midwives, and participants’ (p570)
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Drop-outs due to miscarriage or stillbirth were excluded from the analysis (I = 6, C = 3). Reported as combined figure. 11% further attrition for other reasons (I = 10, C = 13), were included in analysis as continuing smokers (C = 96, I = 102)
Selective reporting (reporting bias)	Low risk	All primary outcomes reported.
Other bias	Low risk	No other bias detected.
Biochemical validation of smoking abstinence (detection bias)	Low risk	Biochemical validation of self-reported smoking cessation with salivary cotinine (< 13 ng/mL)
Blinding of participants and personnel (performance bias) All outcomes	High risk	Women unlikely to be blinded to educational intervention.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	‘FN undertook data collection and was blinded to group allocation until all data had been collected.’ (p570)
Incomplete implementation	Low risk	90% MiQuit participants reported reading all the leaflet at least once
Equal baseline characteristics in study arms	Low risk	There were not differences between trial arms on baseline variables except that more participants in the control arm had smoked in a previous pregnancy (difference adjusted for in analyses)
Contamination of control group	Low risk	Technological intervention so low risk of contamination between study arms