Laken 1995.

Methods	3‐arm, individually‐randomised RCT conducted in Detroit, USA; recruitment dates not reported.
Participants	Sample size: 205 individuals. Inclusion criteria: low‐income women who entered prenatal care at a local clinic before 32 weeks' gestation and who delivered at a tertiary‐level hospital. Exclusion criteria: not reported.
Interventions	Target: community (financial incentive intervention). Arm 1 (51 women): women received gift certificates for each prenatal appointment. Arm 2 (53 women): women received gift certificates and a chance to win in a $100 raffle. Arm 2 (101 women): no financial incentive. Women in all 3 groups were offered $10 for the postnatal interview.
Outcomes	Triap Primary Outcome: kept appointments for antenatal care and postpartum care Review outcomes reported: Primary: ANC coverage (at least 4 visits). Secondary: maternal mortality, health facility deliveries, perinatal mortality. Follow‐up: 6‐8 weeks postpartum.
Notes	Funders: Michigan Health Care Education and Research Foundation. Authors provided unpublished data for coverage, mortality and health facility deliveries by email on 16/1/15.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"random numbers were used" for group assignment.
Allocation concealment (selection bias)	Unclear risk	Not described.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Clinic staff members were blind to assignment, but women would have been aware of their own assignment.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported.
Recruitment bias (for cluster RCTs)	Low risk	Not applicable.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Missing data < 20% for birth outcomes (low risk) but high loss to follow‐up at the postnatal interview (45%).
Selective reporting (reporting bias)	Unclear risk	Relevant outcomes reported, but insufficient data provided.
Analysis bias	Unclear risk	Methods not reported in sufficient detail.
Other bias	Unclear risk	Insufficient information to make a judgement.
Overall risk assessment	Unclear risk	Insufficient information to make a judgement.