Perinatal Outcomes at High Altitude: Analysis of Birth Weight, Low Birth Weight, and Small for Gestational Age in Relation to Maternal Factors: Catamarca, Northwestern Argentina

Abstract

This study compared birth weight (BW) and associated gestational and maternal determinants among newborns from high- and low-altitude regions in Catamarca, northwestern Argentina. A retrospective population-based analysis was conducted using vital records from 1990 to 2010, including 485 births from high-altitude areas (HA; 3,323 m above sea level) and 65,538 births from low-altitude areas (LA; 520 m above sea level). Neonatal outcomes were classified according to international standards: low birth weight (LBW; <2,500 g) and small for gestational age (SGA; <10th percentile). Mann–Whitney U tests, chi-square tests, generalized linear models, and logistic regression was used. Newborns from HA exhibited significantly lower BW and a higher frequency of LBW and SGA compared with those from LA. BW was strongly influenced by gestational age, with preterm birth being the main predictor of reduced weight; the altitude–prematurity interaction showed a partial attenuation of this effect in HA newborns. LBW was associated with preterm pregnancy and younger maternal age, whereas high altitude and post-term pregnancy were associated with SGA. Additionally, younger maternal age and low educational level increased the risk of SGA. These findings demonstrate the combined influence of altitude, fetal maturation, and sociodemographic factors on neonatal outcomes and underscore the need for targeted perinatal strategies in high-altitude populations.