RESUMEN
BACKGROUND: We estimated the benefits and costs of a set of preventive interventions that could be delivered during antenatal care to prevent poor birth outcomes, including small-for-gestational-age and preterm births. We built on the assumptions and analyses underlying the Lancet Series on small vulnerable newborns (SVNs) and extended that work by incorporating more recent data, focusing only on the subset of preventive interventions, and examining a broader range of effects. A primary aim of the study was to provide a framework that decision makers could use to design programmes for women and children. METHODS: The analyses used the Lives Saved Tool (LiST) to estimate the effects and costs of scaling up the 11 preventive interventions identified in the SVN Series to improve birth outcomes. We used LiST estimates of effects and costs to estimate benefit-cost ratios (BCRs) for two intervention packages (one with interventions proven to improve birth outcomes and one with proven interventions plus interventions with potential to improve birth outcomes) and for the individual interventions in these packages for 80 low-income and middle-income countries (LMICs). FINDINGS: Both packages of interventions had BCRs more than 1, with a proven package BCR of 7·3 (IQR 5·3-9·1) and a proven plus potential package BCR of 5·8 (4·4-6·9). We found that in all cases the individual interventions had BCRs more than 1, there was a wide range of BCR values for the different interventions, and the BCR varied depending on package and country. INTERPRETATION: The analyses presented in this Article provide evidence that there are preventive interventions that, if scaled up in LMICs, could have a large effect on child health and provide benefits that greatly exceed the costs. FUNDING: Global Affairs Canada.