Association between social and built environment characteristics and maternal mortality in 340 Latin America cities: an ecological study from the SALURBAL study

Introduction: Maternal mortality ratio (MMR) is a key indicator of maternal health, but heterogeneity across cities has been infrequently explored. We aimed to investigate variation in MMR across cities and the association between social and built environment features of urban areas and MMR in Latin American countries. Methods: This ecological study used harmonised data from the Salud Urbana en América Latina study comprising 340 cities across eight countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Guatemala, Mexico and Panama). MMRs were calculated for each city using vital statistics registries for the years 2012-2016 and a correction factor applied for under-reporting of maternal deaths. Predictors of interest included city social environment characteristics (living conditions, services provision and population educational attainment), built environment characteristics (isolation of urban development, population density and mass transit availability) and total population. Mixed negative binomial regression models with country-level random intercepts were used. Rate ratios (RRs) were estimated. Results: MMR was 47.3 maternal deaths (SD 25.3) per 100 000 live births. Cities with better living conditions and with better services provision had lower MMRs (RR=0.89 per SD, 95% CI=0.82 to 0.97; and RR=0.92 per SD, 95% CI=0.87 to 0.97, respectively), while those with higher urban isolation and population density had higher MMRs (RR=1.07 per SD, 95% CI=1.03 to 1.13; and RR=1.11 per SD, 95% CI=1.04 to 1.19, respectively). Conclusions: We found that better living conditions, service provision and mass transit availability were associated with lower MMR, whereas higher population density and urban isolation were associated with higher ratios. These findings suggest that multisectoral urban policies aimed at improving social conditions, infrastructure and mobility may help reduce maternal mortality in Latin American cities, contributing to improving maternal health and advancing health equity.