Tuten 2012.

Methods	Study design: 3‐armed RCT; May 2005 to January 2009 Country: USA Setting: Center for Addiction and Pregnancy, Baltimore, MD
Participants	102 pregnant, methadone‐maintained smokers, aged 18+, ≤ 30 weeks gestation, nicotine‐dependent or smoking 10+ CPD Contingent behavioural incentives (CBI): 42; non‐contingent behavioural incentives (NCBI): 28; treatment as usual (TAU): 32 Mean age 30.7; mean CPD 18; % unemployed 94.8; mean gestational age 16.5 weeks
Interventions	All participants completed an initial 8‐day residential course, then went to outpatient status. In 1st week, all completed an Addiction Severity Test (ASI), a structured clinical interview for DSM‐IV disorders (SCID), revised FTND. CO testing 3 times a week, urine samples 3 times a week (cotinine) + random cocaine testing once a week ASI repeated at 1 month and 3 months and at 6 weeks post‐partum, + CO and urine tests. At each testing all participants received brief (10 mins) MI feedback. Standard info on adverse effects of smoking for mother and baby All this was classified as ‘Treatment as usual (TAU)’. Experimental Group: CBI: 12 weeks of eligibility for CBI rewards contingent on reduction or abstinence. Incentives for each negative breath test on Mondays, Wednesdays and Fridays, as follows: week 1: any reduction; weeks 2 to 4 10% reduction; weeks 5 to 7: 25% reduction; weeks 8 to 9: 50% reduction; weeks 10 to 11: 75% reduction; week 12 – delivery: abstinence (CO < 4 ppm) Voucher started at USD 7.50 and increased by USD 1 a day up to USD 41.50. If negative sample missed through the 12 weeks, schedule was reset to USD 7.50. If she achieved 5 consecutive negative tests, the voucher value was restored to former level NCBI: “pseudo‐yoked” schedules. NCBI participants were each yoked to a random participant in the pilot study (i.e. had submitted CO samples for at least 2 weeks). Participants were told that their behaviour did not determine rewards received, but that they would receive incentives in line with a previously established schedule. NCBI participants had to give breath and urine samples to receive their scheduled incentive. They were eligible for 12 weeks or until delivery
Outcomes	Primary target outcome was reduction. Abstinence measured at end of 12‐week programme, and 6 weeks post‐partum Cessation was PPA, biochemically verified (CO < 4 ppm; urinary cotinine < 300 ng/ml)
Notes	New for 2015 update
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Participants were assigned randomly"
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Abstinence biochemically validated
Incomplete outcome data (attrition bias) All outcomes	Low risk	CBI: 8/42 lost; NCBI 4/28 lost; TAU 7/32 lost, but all included in ITT analyses.