Methods	Randomised controlled trial (SCRIPT Trial III) of counselling intervention provided by routine care staff (effectiveness study) to support women to stop smoking in pregnancy Study conducted in 16 /67 counties providing Medicaid care in Birmingham, Alabama (USA). Counties matched by number of smokers and percentage Black and White women, and 1 county per dyad (n=8) randomly selected to participate in study. There were 10 prenatal care clinics and 28 regular staff members in the 8 counties selected. Recruitment dates not reported, but study conducted over 5 years
Participants	Inclusion criteria: Pregnant women who reported ≥1 cigarette (‘even one puff’) in the last 7 days, or had a cotinine level ≥20 ng/mL Exclusion criteria: Not further specified. Recruitment: 6,514 women were screened at first antenatal visit and 1340/1736 (77%) eligible smokers agreed to participate. 1 trial site dropped out leaving 1,093 who were randomised (C=546, I=547) Baseline characteristics: Cigarettes per day: C= 9.8 (&10.3 among drop-outs), I=10. 4 (&12.0 among dropouts); Lives with smoker: C=69.8 (&75.3% among dropouts), I=73.7 (&66% among dropouts). Mean cotinine: C=163, I=181 Mean age: 22 years; Black C=15.7%, I=15.4%. Progress+ coding: Low SES as Medicaid clinics.
Interventions	Staff orientation and assessment, and 3 hours SCRIPT training for staff in intervention sites Control: All participants received 4 elements of the “5A’s” best practice guidelines (Ask-Advise-Remind) Intervention: Participants received (Assist) Procedures 4 through 8: (i) A 14 minute ‘Commit to Quit Smoking During and After Pregnancy’ video (ii) A ‘Pregnant Woman’s Guide to Quit Smoking’ written at 6th grade reading level and includes a 10 day self-help guide for cessation (Windsor 1985), and (iii) A ≤10-minute counselling session (MI) Main intervention strategy: Counselling (multiple intervention) compared to a less intensive intervention Intensity: Frequency (C=2, I=2), Duration (C=1, I=2). Intervention provided by existing staff: Effectiveness study
Outcomes	Biochemically validated point prevalence abstinence in late pregnancy* (>60 days after first visit, and <90 days postpartum) Number with a “significant reduction” in cotinine* (>50ng/mL at baseline and <50% at follow up, quitters not included as significant reducers) An additional ‘historical’ control group also provides comparison pre and post intervention
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as ‘randomly selected’ counties. Then “Smokers were randomly assigned at each clinic to an experimental group or control group after screening, consent, and baseline assessment”
Allocation concealment (selection bias)	Unclear risk	Not reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition: C=97/546 (17%) and I=95/547 (17%). Reasons for drop-out not reported. An intent-to-treat policy was used in the computation of impact rates and all dropouts included as continuing smokers in this review
Selective reporting (reporting bias)	Unclear risk	Unclear if there was 1 or 2 assessments (i. e. 1 assessment between >60 days after first visit and <90 days post partum; or 2 ‘assessments performed >60 days after first visit, and <90 days postpartum’). Only 1 assessment reported.
Other bias	High risk	Figures in Table 1 (baseline, C=546, I=547) conflict with the outcome denominator in Table 2, which is reported to include those lost to followup (C=549, I=544). Figures reported in Table 1 used for denominator and Table 2 for numerator in this report
Biochemical validation of smoking abstinence (detection bias)	High risk	72% self-reported quitters validated with biochemical verification (salivary cotinine <20ng/mL). 10% non-disclosure of smoking detected
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and personnel not blinded to counselling intervention
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported.
Incomplete implementation	Low risk	Process evaluation showed reasonable implementation (over 80%)
Equal baseline characteristics in study arms	Unclear risk	Equal on all variables apart from mean cotinine (ng/mL)
Contamination of control group	High risk	Process evaluation suggests there was significant contamination of the randomised control group with regular clinic staff providing the intervention to both study arms

AFP: alpha fetoprotein

ALA: American lung association

AN: antenatal

BP: blood pressure

C: control group

CBT: cognitive behavioural therapy

CI: Confidence interval

CO: carbon monoxide

GP: general practitioner

HMO: Health Maintenance Organisation

I: intervention group

ICC: Intracluster correlation co-efficient

ITT:intention to treat

LBW: low birthweight

MI: motivational interviewing

min: minutes

MRFIT: randomised trial of health promotion carried out in the US

NICU: neonatal intensive care unit

NNTB: number needed to benefit

NRT: nicotine replacement therapy

OPD: out-patient department

Pls: principal investigators

ppm: parts per million

PPROM: preterm, prelabour rupture of the membranes

SD: Standard deviation

SES: socioeconomic status

SHO: senior house officer

TFS: teen fresh start

TFSB: teen fresh start + peer support

UC: usual care

UK: United Kingdom

US: ultrasound

USA: United States

vs: versus

WIC: Food program for Women, Infants and Children in the US