Intrauterine growth restriction, prematurity, and low birth weight: risk phenotypes of neonatal death, Rio de Janeiro State, Brazil

Abstract: Intrauterine growth restriction and prematurity determine low birth weight. The combination of the three conditions results in different neonatal phenotypes that interfere with child survival. Neonatal prevalence, survival mortality were estimated according to cohort live births 2021 state Rio de Janeiro, Brazil. In this study, multiple pregnancies, congenital anomalies inconsistencies information weight gestational age excluded. Intergrowth curve was used classify adequacy. Mortality (< 24 hours, 1-6 7-27 days) (Kaplan-Meier) estimated. total, 6.8%, 5.5%, 9.5% 174,399 weight, small for (SGA), premature, respectively. Considering births, 39.7% SGA 70% premature. heterogeneous maternal, delivery, pregnancy, newborn characteristics. rate per 1,000 high premature newborns, both (78.1) AGA (adequate age: 61.1), at all specific ages. Reductions observed when comparing non-low term births. prevalence values lower than those other studies, partly due exclusion criteria adopted. identified children who more vulnerable higher risk death. Prematurity contributed SGA, its prevention is necessary reduce Janeiro.