Purpose: To evaluate the survival and complications associated with prematurity of infants with less than 32 weeks of gestation.
Methods: It was done a prospective cohort study. All preterm infants with a gestational age between 25 and 31 weeks and 6 days, born alive without congenital anomalies and admitted to the NICU between August 1st, 2009 and October 31st, 2010 were included. Newborns were stratified into three groups: G25, 25 to 27 weeks and 6 days; G28, 28 to 29 weeks and 6 days; G30, 30 to 31 weeks and 6 days, and they were followed up to 28 days. Survival at 28 days and complications associated with prematurity were evaluated. Data were analyzed statistically by c² test, analysis of variance, Kruskal-Wallis test, odds ratio with confidence interval (CI) and multiple logistic regression, with significance set at 5%.
Results: The cohort comprised 198 preterm infants (G25=59, G28=43 and G30=96). The risk of death was significantly higher in G25 and G28 compared to G30 (RR=4.14, 95%CI 2.23-7.68 and RR=2.84, 95%CI: 1.41-5.74). Survival was 52.5%, 67.4% and 88.5%, respectively. Survival was greater than 50% in preterm >26 weeks and birth weight >700 g. Neonatal morbidity was inversely proportional to gestational age, except for necrotizing enterocolitis and leukomalacia, which did not differ among groups. Logistic regression showed that pulmonary hemorrhage (OR=3.3, 95%CI 1.4-7.9) and respiratory distress syndrome (OR=2.5, 95%CI 1.1-6.1) were independent risk factors for death. There was a predominance of severe hemorrhagic brain lesions in G25.
Conclusion: Survival above 50% occurred in infants with a gestational age of more than 26 weeks and >700 g birth weight. Pulmonary hemorrhage and respiratory distress syndrome were independent predictors of neonatal death. It is necessary to identify the best practices to improve the survival of extreme preterm infants.