Abstract

--- - Introduction. Mortality in very low birth weight infants (VLBWIs) has remained at similar to 26% in the past 16 years in the NEOCOSUR Neonatal Network. - Objective. To determine the cause of death of VLBWIs and its temporality in the 2007-2016 period in the NEOCOSUR Neonatal Network. Population and methods. Observational, multicenter cohort study; retrospective analysis of data collected prospectively. Newborninfants born between 24 and 31+6 weeks of gestation age with a birth weight between 500 and 1500 g in the 26 sites of the NEOCOSUR Neonatal Network were included. The causesof death were analyzed depending on whether they occurred in the delivery room (DR) or in the neonatal intensive care unit (NICU). The postnatal age at time of death was determined using the KaplanMeier test. - Results.A total of 11 753 VLBWIs were included; overall mortality was 25.6%. The prevailing causes of death in the DR were congenital malformations (43.3%), respiratory diseases (14.3%), and prematurity (11.4%). The prevailing causes of death in the NICU were respiratory diseases (24.2%) and infections (24.1%). The average and median age at death were 10.2 and 4 days, respectively. Also, 10.2% of deaths occurred in the DR; 21.5% on day 1, 52% in the first 4 days, and 63.8% in the first week of life. - Conclusions. Important differences were observed in the causes of death of VLBWIs depending on their occurrence in the DR or the NICU. Infectiousandrespiratoryconditionswere the most relevant factors following admission to the NICU.