Carroll 1995.

Methods	RCT. No difference between groups on baseline drug use or demographic characteristics.
Participants	20 pregnant women enrolled in methadone maintenance. Mean age 27.6; 78.6% non‐minority (11/14); 78.6% single; 100% unemployed; 8(± 6) weeks gestational age upon entry into MMT; 2.7 mean days cocaine use in past 30 days. Exclusion: > 28 weeks pregnant.
Interventions	Daily MMT, weekly group counselling, three times/week urine toxicology screening for all participants. Weekly prenatal classes, weekly relapse‐prevention groups, childcare during treatment visits, and CM awards ‐ USD15/ week for three consecutive negative urine screens (n = 7). MMT and weekly group counselling (n = 7). No difference between groups in terms of MMT dose (mean 50 mg). Duration: average 23 weeks (range 13 to 31 weeks).
Outcomes	Attendance was measured in terms of % number of groups attended. Infant outcomes measured as mean gestational age at delivery, mean weight, and mean number of days in the hospital. Urine toxicology was measure as % positive for cocaine, opiates, or other drugs.
Notes	Unable to measure retention as not reported. We attempted to contact trial authors but data was unavailable.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"a total of 20 women provided informed consent and were randomly enrolled…" No details were provided related to randomization methods.
Allocation concealment (selection bias)	Unclear risk	Allocation concealment was not described.
Incomplete outcome data (attrition bias) All outcomes	High risk	"A total of 20 women provided informed consent and were randomly enrolled.  Of these, one delivered within 1 week of providing consent, one was hospitalized for sedative detoxification, and four, all of whom had been on the methadone programme for several months or years when they became pregnant, did not participate in any groups or study assessments and were considered dropouts." 20 patients randomized and only 14 analysed. 6 dropouts (unclear from which randomized groups). Exclusions in analysis were lost to follow‐up because they did not attend meetings or because of early labour. These are all possible outcomes of the review and their exclusion biases results. Also analysis was per protocol not ITT.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No references to outcome assessor blinding made.