McBride 2004.

Methods	Setting: Army Medical Centre, USA Recruitment: Pregnant women at first prenatal visit
Participants	583 pregnant current smokers and recent quitters (390 in relevant arms); av. age 24
Interventions	1. Usual care: provider advice and S‐H guide 2. As 1, plus 6 proactive TC calls, 3 in pregnancy, 3 postpartum within 4 m + late pregnancy relapse prevention kit 3. Partner‐assisted intervention, not used in this review
Outcomes	Abstinence at 12 m postpartum (7‐day PP at all 4 follow‐ups) Validation: Saliva cotinine request, incomplete return, rates based on self‐report
Notes	Effect of TC as adjunct to brief advice Effect at 6 m not sustained longer term. Mean number of calls received was 5
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised, method not described, stratified by smoking status
Allocation concealment (selection bias)	Unclear risk	No details given
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Biochemical validation conducted but not used in outcome data. Quote: "Saliva return rates did not differ by condition at either follow‐up" but rates of return low and level of misreport not specified
Incomplete outcome data (attrition bias) All outcomes	Low risk	Loss to follow‐up higher in Intervention (22%) than Control (16%). Losses included as smokers