Objective To systematically evaluate the effectiveness of interventions to increase the early initiation of comprehensive antenatal care in socially disadvantaged and vulnerable women.

Design Systematic review.

Data Sources Major bibliographic databases (Medline, Cinahl, Embase, PsycINFO, HMIC, CENTRAL) and other online libraries and resources were searched to identify relevant English language journal articles published 1990–2009. We included comparative studies (experimental or observational) evaluating the effectiveness of an intervention on the proportion of women initiating antenatal care by any defined cut-off point ≤20 weeks in a disadvantaged or vulnerable population. In order to focus on interventions relevant in the context of the UK National Health Service, we excluded studies from low-income countries and those relating to financial interventions such as extension of health insurance coverage or similar.

Review Methods Two reviewers independently extracted data for eligible studies; assessed internal validity using the GATE checklist and considered whether the studies provided evidence of a beneficial effect.

Results Over 3000 citations were screened. Sixteen eligible studies were identified; 14 conducted in the USA, one in Australia and one in the UK. All were observational evaluations. Twelve studies evaluated interventions targeted at specific disadvantaged or vulnerable subgroups of the population (predominantly ethnic minority women or teenagers); the remaining studies evaluated interventions in more generally socioeconomically disadvantaged populations. Eleven studies evaluated interventions that involved outreach or other community-based services, and five evaluated interventions that involved alternative models of clinic-based antenatal care. Overall, the quality of evidence was poor. Only one study, which evaluated a US home visiting intervention delivered by paraprofessional women to pregnant adolescents, was considered to have adequate internal validity. The reviewers considered the evidence relating to this intervention to be inconclusive but consistent with a possible beneficial effect of the intervention on timing of initiation of antenatal care.

Conclusion We found insufficient evidence of adequate quality to reliably conclude that any of the interventions considered were effective at increasing the early initiation of antenatal care in socially disadvantaged and vulnerable women. There was weak evidence of effectiveness relating to one intervention based on home visiting for pregnant adolescents. Findings were inconclusive for all other included interventions, although we identified several strategies that might warrant further consideration and possibly more robust evaluation. The results of this review highlight the paucity of evidence and the need for further high quality research to ensure that future service innovations are evidence based.