| Methods |
Randomized controlled trial. 24 months. 5 family planning and women's health clinics in northern California (United States), 104 participants. |
| Participants |
Pregnant women who stated intent to obtain prenatal care at participating clinics. |
| Interventions |
2 intervention groups: 1 received taxicab voucher to/from first prenatal visit; the second received baby blanket voucher to be redeemed at first prenatal visit. Control group received standard prenatal care. |
| Outcomes |
Compliance with attending first prenatal visit. |
| Notes |
The blanket intervention group had poor compliance with primary outcome and was combined with the control group for stratified analysis in the original study, although data for the primary outcome were reported accurately. Given that the 2 interventions were similar in terms of potential value to patients, we felt it was more accurate to combine data from the 2 intervention groups for the purposes of this review. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Blocked by clinic. Within each clinic, assignment was by computer random number table. |
| Allocation concealment (selection bias) |
Low risk |
Sequentially numbered, opaque, sealed envelopes. |
| Blinding of participants and personnel (performance bias)
All outcomes |
High risk |
Participants were aware of their voucher offer, but it was not clear whether they were aware of other assignment groups voucher offer. Clinician blinding was not described. |
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
Outcome assessor was blinded to group assignment. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Intention‐to‐treat. Loss to follow‐up was a study outcome. |
| Selective reporting (reporting bias) |
High risk |
Reporting differed from protocol in that 1 of the intervention groups had poor compliance with primary outcome and was combined with the control group for stratified analysis. The original data for all 3 groups were reported accurately. |
| Other bias |
Low risk |
No other sources of bias detected. |
