Methods	A randomised controlled pilot study to evaluate whether medical advice had a effect on smoking cessation in pregnancy Study conducted in Bolton, England. Years of data collection not reported
Participants	Inclusion criteria: Pregnant smokers at their first antenatal visit, less than 20 weeks’ gestation Exclusion criteria: Not reported. Recruitment: Women recruited from public antenatal clinic at Bolton and District General Hospital. 510 women screened, 142 eligible, 8 moved house and could not be followed up, and 24 women had spontaneously quit. 110 women randomised: control = 47, intervention = 63 Baseline characteristics: 89% heavy smokers and 75% had been smoking for 5 years or more 72% ‘working-class’ (majority low SES) and 75% had no educational qualifications Progress+ coding: Low SES and low educational attainment.
Interventions	Control: Usual care, which was advice at the discretion of the doctor. Intervention: 1 to 1 counselling (‘a short interview’) from a senior medical student which involved discussion of the disadvantages of smoking during pregnancy: risk to the fetus; long-term risks of physical and intellectual impairment and possible reasons for this; possible effects on the mother’s own health; costs of smoking; special dangers of smoking in late pregnancy; various ways to help someone to stop smoking. Given strong encouragement to quit and to make a commitment to do so. If this was not agreed then reduction to less than 5 cigarettes a day. Half the intervention group were given a diary to record each cigarette smoked and a gift of a free smoking diary Main intervention strategy: Counselling (single intervention) compared with usual care. Intensity: Frequency (C = 0, I = 1); Duration: (C = 0, I = 1). Usual care intensity: Frequency = 1, duration = 1. Intervention conducted by existing staff (medical student): effectiveness study
Outcomes	Self-reported abstinence 11 weeks after baseline visit (late pregnancy*) Smoking reduction reported for whole cohort, not by intervention group, therefore not included in this review Discusses participants’ views of intervention.
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information provided. Described as “randomly divided”.
Allocation concealment (selection bias)	Unclear risk	No information provided.
Incomplete outcome data (attrition bias) All outcomes	Low risk	There are some missing data in the tables. It is not clear if there was any overall loss to follow-up or whether missing data relate to specific outcomes only. All randomised women included in this review and those lost to follow-up were included as continuing smokers in this review
Selective reporting (reporting bias)	Unclear risk	No other outcomes reported.
Other bias	Low risk	No other bias detected.
Biochemical validation of smoking abstinence (detection bias)	High risk	Smoking outcomes were self-reported by participants during a visit at home. There was no biochemical validation
Blinding of participants and personnel (performance bias) All outcomes	High risk	Educational intervention at first antenatal visit.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported.
Incomplete implementation	Unclear risk	Not reported.
Equal baseline characteristics in study arms	Unclear risk	Not reported.
Contamination of control group	Low risk	Medical student provided intervention (not usual care provider)