Methods	Randomised controlled trial of counselling interventions to support women to stop smoking in pregnancy Study conducted in a public antenatal clinic in Melbourne, Victoria, Australia. Data collected from April 1994 to June 1996
Participants	Inclusion criteria: Women who identified as “current smokers” at their first antenatal visit at approximately 12 weeks’ gestation (“even a puff in the last 7 days”) Exclusion criteria: >20 weeks’ gestation; twin pregnancy; not literate in English; drug dependency Recruitment: 9193 women screened, 1942 (21%) current smokers and 625 (7%) spontaneous quitters (not included in study but described in Panjari 1997). 1013/1942 smokers (52%) agreed to participate (929 refused or not eligible) and were randomised (C = 537, I = 476). Baseline characteristics: Mean cigarettes per day = 21 before pregnancy and 11 at time of first antenatal visit. 74% had a smoking partner Mean age 26 years. Progress+ coding: Low SES as authors note mostly low income women.
Interventions	Control: Usual care, which included advice at the discretion of the caregiver, and 0 pamphlet “Smoking & Pregnancy” distributed during a group pregnancy information session Intervention: As for the control group plus 4 counselling sessions by a midwife specifically trained and employed to provide smoking cessation counselling, using CBT. Sessions included video presentation, interactive discussion and strong verbal messages. These were followed up with a 5 to 10 minute personalised counselling session Main intervention strategy: Counselling (single intervention) compared to usual care. Intensity: Frequency (C = 0, I = 3), Duration (C = 0, I = 3). Usual care intensity: F = 1, D=1 Intervention provided by dedicated project staff: efficacy study
Outcomes	Self-reported smoking cessation biochemically validated with urine cotinine at 36 weeks’ gestation (late pregnancy*), 6 weeks postpartum (0-5 months)*, and 6 months (6-11 months*) postpartum*. Preterm births*, mean birthweight*, proportion LBW* (< 2500 g) Reduction in mean cigarettes/day* and mean urinary cotinine levels* Breastfeeding at 6 weeks and 6 months postpartum. General health assessment at first visit and 36 weeks General health questionnaire (including stress and depression measurement) at baseline and end of pregnancy
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information.
Allocation concealment (selection bias)	Unclear risk	Described as “randomly allocated".
Incomplete outcome data (attrition bias) All outcomes	Low risk	28% attrition (381/1013). 72/1013 (C = 35, I = 37) were excluded as they were over 20 weeks’ gestation, had a twin pregnancy or were transferred to the chemical dependency clinic. 209/1013 (C=109, I=100) excluded due to transfer to another hospital, miscarriage, termination of pregnancy and withdrawal from the study. The numbers of those who withdrew from the study were not reported separately in this group, therefore all were re-included as continuing smokers in this review (but were not included in mean outcome data)
Selective reporting (reporting bias)	Low risk	A detailed list of birth outcomes reported.
Other bias	Low risk	No other bias detected.
Biochemical validation of smoking abstinence (detection bias)	Low risk	Urinary cotinine levels measured at baseline and in late pregnancy (< 115/ng/mL)
Blinding of participants and personnel (performance bias) All outcomes	High risk	Educational intervention delivered by clinic midwife.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported.
Incomplete implementation	High risk	Process evaluation showed 71% women in the intervention group received the full intervention
Equal baseline characteristics in study arms	Low risk	There were no statistically significant differences between women allocated to the intervention and the control groups in terms of socio-demographic variables and smoking patterns
Contamination of control group	Low risk	Intervention provided by a research mid-wife, not usual care provider