| Methods | Eight West Los Angeles County prenatal clinics randomised to be either experimental or control clinics. Women in experimental clinics offered a programme of more frequent visits, preterm birth prevention education, psychosocial and nutritional screening and crisis intervention. Women in control clinics offered routine county care plus psychosocial and nutritional screening and crisis intervention | |
| Participants | 1774 high-risk patients in experimental clinics and 880 control clinic patients. Majority of patients were Hispanic | |
| Interventions | Women in control clinics offered visits at 4-week intervals up to 30 weeks’ gestation, 2-week intervals from 30-35 weeks’ gestation, and then weekly until delivery. Psychosocial and nutritional screening and crisis intervention also offered. Women in experimental clinics offered visits at 2-week intervals, 3 classes regarding preterm birth prevention, psychosocial and nutritional screening and crisis intervention. Participants were randomised to 1 of 4 secondary interventions (bed rest, social work, Provera or Provera-matched control) or to no additional intervention | |
| Outcomes | Preterm birth rate, costs of antenatal care, inpatient preterm labour, delivery and postpartum care, and newborn care. For continuous outcomes (costs and number of antenatal visits) means and standard errors were reported. We calculated standard deviations in order to include these data in the data and analyses tables | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors’ judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Cluster randomised therefore not applicable; “these clinics were randomized with a restricted block (grouped by size and percent black) randomized scheme to identify the clinic as either experimental (five clinics) or control (three clinics)” |
| Allocation concealment (selection bias) | Unclear risk | Cluster randomised therefore not applicable. |
| Blinding (performance bias and detection bias) All outcomes |
High risk | Women randomised based on which clinic they attended. |
| Incomplete outcome data (attrition bias) All outcomes |
Unclear risk | All high-risk women accounted for in a flow chart. 5%-7% of women assessed as high risk lost to follow-up |
| Other bias | Low risk |
PROM: preterm rupture of membranes