BThis review had clear inclusion criteria for participants, outcomes and study designs. Inclusion criteria for interventions were broad and, as noted by the authors, whether an intervention was defined as initiated in primary care could depend on the quality of reporting in the study report. This suggests that the review could have been influenced by subjective decisions in study selection, as does the decision to include two studies from countries that were otherwise excluded. The search covered a number of sources but was limited to English language publications, suggesting possible language bias. Unpublished studies were not sought and risk of publication bias was not assessed. Study validity was assessed and the results were exploited in the analysis. Attempts were made to reduce errors and bias in validity assessment and data extraction, but methods of study selection were not clearly reported. Relevant details of included studies were provided. Studies were pooled by meta-analysis and heterogeneity was assessed and possible sources explored. Significant heterogeneity was present for most breastfeeding outcomes, reflecting heterogeneity in study participants and interventions. Only a few studies reported direct effects on health outcomes. The authors' conclusions reflect the evidence presented and are likely to be reliable but their clinical significance is uncertain. Their recommendation for further research appears appropriate.