Maternal and Environmental Influence on Birth Weight in Jujuy, Argentina (1991–2014)

INTRODUCTION: Birth weight (BW) is a key indicator of intrauterine growth, influenced by maternal and environmental factors, including geographic altitude. This study analyzes the influence of maternal and socio-environmental factors on BW between 1991 and 2014 in the province of Jujuy, Argentina. METHODS: A total of 310 793 live births in Jujuy were analyzed, grouped by maternal region of residence. Mean BW was estimated, and the percentage distribution of maternal and gestational variables was described. Three-level generalized linear models were applied to assess the association between BW and these variables, accounting for longitudinal and spatial variability. RESULTS: Mean BW was lower in high-altitude regions, with an adjusted difference of ~150 g between highlands and lowlands (p < 0.001). Preterm births, adolescent mothers, and mothers not cohabiting with a partner were associated with lower average BW, while post-term births or mothers with lower educational attainment had higher BW. Adjusted models confirmed differential patterns by altitude, highlighting significant effects (p < 0.001) of maternal and gestational factors. CONCLUSION: In Jujuy, between 1991 and 2014, BW showed a significant association with geographic altitude and maternal factors such as age, marital status, and gestational age, with regional variations. Understanding and addressing these interactions is essential to reduce maternal and neonatal morbidity and mortality.