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Perinatal factors associated with neonatal mortality in very low birth weight infants: a multicenter study.

INTRODUCTION
Objectives. To assess risk factors associated withneonatal mortality in very low birth weight (VLBW) infants (< 1500 g) and the impact of the administration of antenatal corticosteroids.


POPULATION AND METHODS
Retrospective analysis of a VLBW infant cohort from 26 tertiary care and teaching sites member of the South American Neonatal Network (NEOCOSUR), which includes Argentina, Brazil, Chile, Paraguay, Peru, and Uruguay, conducted between 2000 and 2011 on 11 455 records. Maternal and neonatal characteristics and morbidity were compared between deceased VLBW infants and those who survived to discharge. Outcome measures associated with neonatal mortality were established by logistic regression. The effect of antenatal corticosteroids on neonatal morbidity and mortality was estimated using the matching method.


RESULTS
The neonatal mortality rate was 22.3%, and variability among sites was elevated. Factors that were independently associated with a lower mortality of VLBW infants included the administration of antenatal corticosteroids (OR: 0.49, 95% CI: 0.43-0.54), a better birth weight Z-score (OR: 0.63, 0.61-0.65), arterial hypertension (OR: 0.67, 0.58-0.77), and C-section (OR: 0.75, 0.65-0.85). The matching method allowed reducing the risk of death by 38% in association with antenatal corticosteroids.


CONCLUSIONS
Major perinatal factors were identified in association with neonatal mortality in VLBW infants, and the impact of antenatal corticosteroid use in the NEOCOSUR Network was demonstrated.