The rate of very low birth weight infants who have died or sustained long-term morbidity have decreased, but a high proportion of these children remains, according to study results published online.
Jeffrey D. Horbar, MD, and colleagues from the University of Vermont in Burlington reviewed records of 355,806 infants with birth weights ranging from 501 g to 1,500 g who were born between 2000 and 2009. The researchers examined the rates of mortality during initial hospitalization and morbidity in surviving infants, which included early and late infection, chronic lung disease, necrotizing enterocolitis, severe retinopathy of prematurity, severe intraventricular hemorrhage and periventricular leukomalacia. They used data from 669 North American hospitals in the Vermont Oxford Network.
Horbar and colleagues said there was a decrease in the mortality rate of very low birth weight (VLBW) infants, from 14.3% to 12.4%, and major morbidity in surviving infants decreased from 46.4% to 41.4%.
The investigators said, in 2009, 49.2% of all low birth weight infants died or survived with a “major neonatal morbidity.” That number rose to 89.2% for infants who weighed 501 g to 750 g.
“Our findings should only be interpreted as reflecting the outcomes for infants receiving care at North American hospitals with NICUs and should not be generalized to the population of all live-born infants of 501 to 1,500 g or to those treated in NICUs outside of North America,” the researchers wrote, adding that survival and mortality rates vary widely among developing countries. “Because this is not a population-based study, these data should be interpreted with caution if used for prenatal counseling.”
Disclosure: Dr. Horbar is an employee of the Vermont Oxford Network.