Changing trends of neonatal and postneonatal deaths in very-low-birth-weight infants.

Advances in perinatal care have resulted in a decline in mortality of very-low-birth-weight infants (< 1.5 kilograms) and also in an extension of the mortality period. To determine the current relevance of neonatal mortality results as indicators of outcome, all deaths among 427 very-low-birth-weight infants admitted during 1975-1977 were documented. A total of 145 infants died; 90 of the deaths (62%) occurred during the early neonatal period (0 to 6 days), 35 (24%) in the late neonatal period (7 to 27 days), and 20 (14%) in the postneonatal period. Death in 17 of the 20 postneonatal losses was due to neonatal complications of prematurity, and 16 of the 20 deaths occurred during the initial hospitalization. The postponement of these deaths to the postneonatal period has important epidemiologic implications and indicates a need for a reconsideration of accepted reporting mechanisms for infants of very low birth weight.