Methods	Randomised controlled trial of a counselling intervention to support women to stop smoking in pregnancy Study conducted in a public hospital antenatal clinic in Newcastle, Australia, with screening from January 1990 to May 1991
Participants	Inclusion criteria: Pregnant women attending their first antenatal clinic appointment who answered yes to ‘Are you a smoker?”, were less than 26 weeks’ gestation, ill or psychologically unwell Exclusion criteria: Not further specified. Recruitment: 1,909 pregnant women were screened by midwives, 725 smokers (38%). 293/538 (54%) eligible women agreed to participate and were randomised (C = 145, I = 148) Baseline characteristics: Not reported. Progress+ coding: None
Interventions	Control: Doctor and midwife both informed women that smoking was an important cause of pregnancy problems and they should stop; Midwife provided a package (sticker, pamphlet on risks of smoking and 2-page cessation guide), none of which were specifically tailored to pregnant women. Intervention (CBT): (i) 2-3 minute standardised risk information from Doctor. (ii) 14 minute video on risk information rebuttal of barriers to quitting, cessation tips and 10-minute standardised information (iii) Counselling from midwife after the video, using a flip chart, with negotiation of a quit date whenever possible (iv) Self-help manual on risks, barriers and cessation plus 4 packets of confectionary gum (v) Lottery chance (4 prizes) for biochemically validated abstainers at the next visit (vi) Social support from accompanying adult (partner/friend/other) via support tip sheet, contract and form letter, chart, reminder sticker in the medical record, form-letter and sticker from 1st visit Midwife mailed within 10 days + 2nd visit and 34 to 36 week visit 5 minute counselling from Midwife and 1-2 minute risk advice from Doctor. Women still smoking at 34-36 weeks were advised to attend an external cessation course Main intervention strategy: Counselling (tailored) compared to a less intensive intervention Intensity: Frequency (C = 2, I = 3); Duration (C = 1, I = 2). Intervention provided by existing staff: Effectiveness study
Outcomes	Biochemically validated point prevalence abstinence at 34 weeks’ gestation (late pregnancy*) and 6-12 weeks’ postpartum*. Preterm births* are reported in attrition and re-included in both numerator and denominator for this outcome Program costs and time commitments. Discussion of provider views and implementation issues in associated reference (Walsh 2000).
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer-generated.
Allocation concealment (selection bias)	Low risk	Described as “precoded questionnaires in manila envelopes”.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Attrition 14% due to: Leaving clinic (C = 7, I = 7), miscarriage or termination (C = 10, I = 10), and preterm birth (C = 3, I = 4), leaving 252 included in analysis (C = 125, I = 127) 25% lost to follow-up and further missing data for some variables including cotinine validation, however those with missing data were treated as continuing smokers in the analysis
Selective reporting (reporting bias)	Unclear risk	Only smoking outcomes reported.
Other bias	Low risk	No other bias detected.
Biochemical validation of smoking abstinence (detection bias)	Low risk	Urinary cotinine was measured and revealed discrepancy with self-reported smoking status. biochemically validated with salivary cotinine (I = 86%, C = 78%) Cotinine data inconsistent with self-report were 52% in controls and 12% in the intervention group
Blinding of participants and personnel (performance bias) All outcomes	High risk	Educational intervention by usual care providers and notes flagged
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported.
Incomplete implementation	High risk	Midwives involved in recruitment to the trial had variable ‘success’ in consent rates (9%-76%). Overall participation was quite low (54%)
Equal baseline characteristics in study arms	Low risk	Report states baseline characteristics were equal on 12 variables tested
Contamination of control group	Unclear risk	Same care providers for both groups.