Objective: To identify changes in mortality and neonatal morbidities for infants with birth weight 501 to 1500 g born from 2000 to 2009.
Methods: There were 355806 infants weighing 501 to 1500 g who were born in 2000-2009. Mortality during initial hospitalization and major neonatal morbidity in survivors (early and late infection, chronic lung disease, necrotizing enterocolitis, severe retinopathy of prematurity, severe intraventricular hemorrhage, and periventricular leukomalacia) were assessed by using data from 669 North American hospitals in the Vermont Oxford Network.
Results: From 2000 to 2009, mortality for infants weighing 501 to 1500 g decreased from 14.3% to 12.4% (difference, -1.9%; 95% confidence interval, -2.3% to -1.5%). Major morbidity in survivors decreased from 46.4% to 41.4% (difference, -4.9%; 95% confidence interval, -5.6% to -4.2%). In 2009, mortality ranged from 36.6% for infants 501 to 750 g to 3.5% for infants 1251 to 1500 g, whereas major morbidity in survivors ranged from 82.7% to 18.7%. In 2009, 49.2% of all very low birth weight infants and 89.2% of infants 501 to 750 g either died or survived with a major neonatal morbidity.
Conclusions: Mortality and major neonatal morbidity in survivors decreased for infants with birth weight 501 to 1500 g between 2000 and 2009. However, at the end of the decade, a high proportion of these infants still either died or survived after experiencing ≥ 1 major neonatal morbidity known to be associated with both short- and long-term adverse consequences.