Risk factors and neonatal/infant mortality risk of small-for-gestational-age and preterm birth in rural Nepal.

OBJECTIVE Our study seeks to elucidate risk factors for and mortality consequences of small-for-gestational-age (SGA) and preterm birth in rural Nepal. In contrast with previous literature, we distinguish the epidemiology of SGA and preterm birth from each other. METHODS We analyzed data from a maternal micronutrient supplementation trial in rural Nepal (n = 4130). We estimated adjusted risk ratios (aRR) for risk factors of SGA and preterm birth, and aRRs for the associations between SGA/preterm birth and neonatal/infant mortality. We used mutually exclusive categories of term-appropriate-for-gestational-age (AGA), term-SGA, preterm-AGA, and preterm-SGA (with term-AGA as reference) in our analyses. RESULTS Stunted (<145 cm) and wasted (<18.5 kg/m(2)) women both had increased risk of having term-SGA (aRR 1.36, 95% CI: 1.14-1.61, aRR 1.22, 95% CI: 1.09-1.36 respectively) and preterm-SGA (aRR 2.48, 95% CI: 1.29-4.74, aRR 1.99, 95% CI: 1.33-2.97 respectively), but not preterm-AGA births. Similar results were found for low maternal weight gain per gestational week. Those born preterm-SGA generally experienced the highest neonatal and infant mortality risk, although term-SGA and preterm-AGA newborns also had statistically significantly high mortality risks compared to term-AGA babies. CONCLUSIONS SGA and preterm birth have distinct risk factors and mortality patterns. Maternal chronic and acute malnutrition appear to be associated with SGA outcomes. Because of high SGA prevalence in South Asia and the increased neonatal and infant mortality risk associated with SGA, there is an urgent need to intervene with effective interventions.