Methods	Trial of telephone support for improving outcomes in late pregnancy, in the outpatient department of a large maternity hospital in New Zealand, or its associated GP practices, or self-referral, from March to December 1993
Participants	Women with telephone access, who were either single or with an unemployed partner, were recruited before 20 weeks’ gestation. The eligible population was 221 women of whom 131 took part (103 OPD, 22 from GPs, 6 self-referred). 49 were never located, 23 were not interested, 10 refused after explanation, 8 moved away, did not speak English or had a miscarriage. Over 50% of women smoked at recruitment.
Interventions	Introductory letter, phone call, full discussion of “Healthy Mothers/Healthy Babies”. Controls: package of publicly available educational material on healthy behaviours during pregnancy. High intensity intervention: package plus weekly telephone call from trained volunteer with the aim of providing minimal support until 12 weeks afterbirth; aim “to be a friend and a good listener”; to ask about symptoms; signs; alcohol; drugs; smoking and meals in every call; to encourage attendance at antenatal clinic appointments and to ask about “feeling stressed”. Intervention provided by 19 female volunteers, trained for the project with a “case load” of 2 to 6 women each. Theoretical basis: social support. Intensity rating: I = 4, C = 1
Outcomes	Smoking cessation at 34/40. Anxiety and depression scores at baseline and 34/40. There were other intervention components which might have influenced these outcomes
Notes	No process evaluation is reported. No sample size justification
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Yes	Computer-generated random assignment to control or intervention in balanced blocks of 50
Allocation concealment?	Unclear	No information provided.
Blinding? Women and clinical staff	Yes	Caregiver blinded to allocation. Women not blinded to intervention
Incomplete outcome data addressed? All outcomes	Unclear	Attrition was relatively low (9 of 131 women were lost to follow up) but there was a high non-participation rate. Attrition = 7%. Women lost to follow up were included in the analysis as continuing smokers
Free of selective reporting?	Unclear	None apparent.
Free of detection bias?	No	No biochemical validation of reported smoking behaviour.