A Global Ecological Analysis of Maternal Mortality Ratios: Income Level, Health Risks, and Socioeconomic Indicators

Purpose: This study aimed to examine the associations between maternal mortality ratios, selected health risk factors, and socioeconomic indicators at the country level, and to evaluate whether socioeconomic indicators improved the explanatory power of models including population-level health risk factors.Method: This country-level ecological study used publicly available data from the World Health Organization Global Health Observatory and the World Bank Open Data platform. Data were primarily extracted for 2019, and the closest available year was used when 2019 data were missing. Descriptive analyses included up to 151 countries, while hierarchical regression analyses included 102 countries with complete data. The maternal mortality ratio was transformed using the natural logarithm [ln(MMR)] due to its skewed distribution. Associations with selected health risk factors and socioeconomic indicators were examined using Pearson correlation and hierarchical regression analyses.Results: The mean maternal mortality ratio was 126.11±185.90 per 100,000 live births, indicating substantial crosscountry variation. Maternal mortality differed significantly by income group, with the highest log-transformed values in low-income countries and the lowest in high-income countries. Maternal mortality was most strongly and negatively correlated with female secondary school enrollment. In hierarchical regression, health risk factors explained 44.7% of the adjusted variance in maternal mortality (adjusted R² = 0.447). After the addition of socioeconomic indicators, the adjusted explained variance increased to 61.8% (adjusted R² = 0.618). Female secondary school enrollment showed the strongest association with maternal mortality in the final regression model.Conclusions: Cross-country differences in maternal mortality were strongly associated with socioeconomic indicators, particularly female secondary school enrollment. These findings suggest that strengthening maternal health services together with investments in female secondary education, health literacy, gender equity, and nursing-oriented preventive strategies may contribute to improving maternal health outcomes.