Abstract

This study investigates the socio-economic determinants of infant mor- tality rates using panel data from the World Bank’s World Development Indicators (WDI) for over 100 countries spanning multiple decades. Given the potential endogeneity in the fertility-mortality relationship, a two-stage least squares (G2SLS) instrumental variable (IV) approach is employed, us- ing the second lag of fertility as an instrument. This strategy accounts for reverse causality and omitted variable bias, ensuring more robust estimates of the causal effect of fertility on infant mortality. A fixed-effects regres- sion model is implemented to analyze the dynamic effects of fertility rate, real GDP per capita, urbanization, and economic growth on infant mortal- ity, incorporating interaction terms to examine how economic development moderates the impact of fertility. The results confirm that higher fertility rates are associated with increased infant mortality, but this effect dimin- ishes in wealthier economies, highlighting the role of economic development in mitigating child mortality risks. Additionally, urbanization and short- term economic growth exhibit significant negative associations with infant mortality, underscoring the importance of healthcare access and economic stability in improving child health outcomes.