Factores de riesgo y seguimiento clínico en prematuros menores de 1 000 gramos

background: extremely low birth weight infants (elbw) outcome has improved in the last years, but morbi-mortality and sequels are still high. objective: to define neonatal morbidity and mortality by weight intervals, their main causes and associated risk factors. establish critical survival weight and most frequent complications in one year follow-up. method: all elbw newborns between 2000-2004 were included, except those less than 24 weeks of gestation and 500 g. perinatal and evolution data were recorded. results: of 212 newborns, 196 entered the nicu, 63% received antenatal corticosteroids, 59% were born by cesarean section and 28% had apgar test d"5 at 5’. 82% presented hmd, 37% symptomatic ductus and 24% severe intraventricular hemorrhage. the survival rate significantly improved above 800 grams. 117 infants died (55.2%), in which 56% occurred before the 7th day of life, 40% were attributed to infectious diseases and 25% to respiratory causes. of the survivors, 82% needed ventilatory support, 47% had bronchopulmonary dysplasia and 80% developed retinopathy. at one year corrected age, 54% required hospitalization, 20% presented moderate to severe neuromotor disability and 15% had moderate to severe impairment psychomotor development. conclusions: elwb survival was 44.8% in the quiquenium with continuous increase, associated to an improve in caesarean deliveries and decrease of low apgar tests. it is possible to improve even more, in order to reduce nosocomial infection rate. more and better measures of prevention and rehabilitation will reduce sequels at long term