Methods	Randomised trial of psychosocial support in pregnancy in 4 hospitals in Latin America (Argentina, Brazil, Cuba, Mexico). January 1989 - March 1991
Participants	High-risk women whose antenatal care began at 15-22 weeks’ gestation, singleton pregnancy, 1 or more of the following: prior LBW infant; preterm birth; perinatal/infant death; <18 years; body weight <= 50 kg; height <= 150 cm; low family income (local definitions applied); < 3 years school; crowded household (4 or more persons/bedroom); smoking; not living with husband or partner. 2235 women recruited 1115 to intervention 1120 to control. Exclusions: heart or renal failure; diastolic BP >100 mmHg; history of cervical cerclage; Rh negative; mental disease or any chronic disease that might interfere with pregnancy
Interventions	Control group received routine antenatal care. Intervention involved flexible use of a standardised manual, based on site-specific ethnographic studies of needs, fears, expectations, social support networks, including detailed descriptions of situations likely to occur during home visits. 4 to 6 home visits of 1 to 2 hours with emphasis on psychosocial support, education on health habits including better nutrition, reducing smoking alcohol and other drugs, reducing their physical workload, recognition of alarm signs and symptoms, improved access to hospital facilities, reinforcement of health service utilization. Additional components were a poster, a booklet, hotline to project office, guided tour of hospital, encouragement of family support and participation. Intervention was provided by specially trained female social workers or obstetric nurses with previous experience of childbirth. Theoretical basis: reinforcement of social support networks. Intensity rating: I = 4, C = 1
Outcomes	Self-reported smoking cessation, no biochemical validation. Multiple perinatal and maternal health outcome data were collected Baseline state anxiety score.
Notes	Sample size was planned for the primary trial objective. Process evaluation showing good implementation is reported.
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	Centrally prepared, method not stated.
Allocation concealment?	Yes	Allocation was by opening sealed, opaque envelopes.
Blinding? Women and clinical staff	No	Home visitors were aware of group allocation. Social support intervention with home visits
Incomplete outcome data addressed? All outcomes	No	Nine per cent lost to follow up. No ITT analysis of drop-outs as continuing smokers
Free of selective reporting?	Unclear	None apparent.
Free of detection bias?	No	No biochemical validation of reported smoking behaviour.