Methods	3-armed randomised controlled trial of personalised feedback during ultrasound and counselling to support women to stop smoking in pregnancy The study was conducted in Women, Infant and Child (WIC) clinics in Houston and Harris County Area, University of Texas Houston Medical School obstetric clinics and the local community (USA). Recruitment years not reported
Participants	Inclusion criteria: Pregnant women reporting having smoked a cigarette in the past 7 days; age 16 years and older; English speaking, and gestational age between 16 and 26 weeks (to recruit later-pregnancy continuing smokers who have had the most difficulty stopping smoking for the pregnancy) Exclusion criteria: Not further specified. Recruitment: Via routine prenatal screening and widely distributed advertisements. 4, 258 women were screened. 360/725 (49.6%) of eligible women agreed to participate and were randomly assigned to 3 conditions: C (BP) = 120, I1 (BP + US) = 120, I2 (MI + US) = 120. Baseline characteristics: Mean number of cigarettes per day: C = 11.72 (8.73), I1 = 11.78 (9.47), I2 = 11.03 (8.14). Partner smoking: C = 68 (68), I1 = 82 (79.6), I2 = 76 (72.4). Baseline cotinine: C = 117, I1 = 116, I2 = 131. Mean gestational age: C = 23.63, I2 = 22.48, I2 = 21.12; Mean age: 24.65, I1 = 25.45, I2 = 25.21; Mean years education: C = 11.40, I1 = 11.37, I 2= 11.63; White: C = 65. 22%, I1= 57.02%, I2 = 49.57% (remainder African-American and Hispanic); Income <$US15,000/yr: C = 49.58%, I1 = 55.85%, I2 = 56.67%. Progress+ coding: Low SES.
Interventions	Control (BP): Best Practice or “BP” counselling based on the Agency for Healthcare Research Quality practice guidelines for identifying patients who smoke and intervening for smoking cessation (5A’s and 5R’s). Nurses trained and instructed to keep counselling to 10-15 minutes. Participants were also given American Cancer Society literature on prenatal smoking cessation and the toll-free number for the quit smoking hotline Intervention 1: BP+ Ultrasound feedback sessions lasting approximately 30 minutes . In addition to providing routine ultrasound results, the ultrasound session was designed to provide information regarding the effect of cigarette smoke on the fetus using a motivational style. The sonographers received 2 hours of training and a laminated prompt card. Smoking risk messages were incorporated into discussion Intervention 2: BP+US+ Motivational Interviewing consisting of 1 45- to 50-min, face-to-face, individual counselling session conducted immediately after the ultrasound; 1 personalised feedback letter mailed 1 week later; and 1 follow-up counselling session conducted via telephone 2 weeks subsequent to the initial session, provided by master’s level counsellors. Elements of the transtheoretical model were included and smoking in the household and social networks were also addressed Main intervention strategy: Feedback (multiple intervention) compared to a less intensive intervention Intensity: Frequency: (C = 2, I = 4), Duration: (C = 1, I = 3). Intervention provided by dedicated study staff: Efficacy study
Outcomes	Biochemically validated smoking cessation at 8 months gestation (late pregnancy*) ‘Predictors of abstinence’ including: Stages of change, depression (Beck’s Depression Inventory), baseline smoking, ethnicity, and social networks reported
Notes	Concerns about potential distress with the ultrasounds intervention were considered in a pilot study of 30 women (Groff 2005) indicated no significant increase in anxiety post-ultrasound
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A block randomisation method, using blocks of 6 (2 per condition), was used to generate 360 slots, 120 per intervention group
Allocation concealment (selection bias)	Unclear risk	Not reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition:16/360 (4.4%), C = 6, I1 = 5, I2 = 5 (reasons not reported). Analyses were conducted using an ITT approach with all randomised participants included in the baseline and those lost to follow-up treated as continued smoking
Selective reporting (reporting bias)	Low risk	Primary outcomes reported.
Other bias	Low risk	No other bias detected.
Biochemical validation of smoking abstinence (detection bias)	Low risk	Self-reported smoking status biochemically validated using salivary cotinine (< 20 ng/mL)
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not feasible to blind participants and personnel to counselling intervention
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Outcome assessor blinding not reported.
Incomplete implementation	Unclear risk	Procecss evaluation not reported.
Equal baseline characteristics in study arms	Low risk	Treatment group differences only for gestational age at baseline
Contamination of control group	Low risk	Low risk of contamination as counselling provided by specialist counsellors, not accessible to the control group