Very low birth weight outcomes of the National Institute of Child Health and Human Development Neonatal Research Network, January 1995 through December 1996

Objectives. To determine the mortality and morbidity for infants weighing 4 01 to 1500 g (very low birth weight [VLBW]) at birth by gestational age, bi rth weight, and gender. Study Design. Perinatal data were collected prospectively on an inborn coho rt from January 1995 through December 1996 by 14 participating centers of t he National Institute of Child Health and Human Development Neonatal Resear ch Network and were compared with the corresponding data from previous repo rts. Sociodemographic factors, perinatal events, and the neonatal course to 120 days of life, discharge, or death were evaluated. Results. Eighty four percent of 4438 infants weighing 501 to 1500 g at birt h survived until discharge to home or to a long-term care facility (compare d with 80% in 1991 and 74% in 1988). Survival to discharge was 54% for infa nts 501 to 750 g at birth, 86% for those 751 to 1000 g, 94% for those 1001 to 1250 g, and 97% for those 1251 to 1500g. The incidence of chronic lung d isease (CLD; defined as receiving supplemental oxygen at 36 weeks' postmens trual age; 23%), proven necrotizing enterocolitis (NEC; 7%), and severe int racranial hemorrhage (ICH; grade III or IV; 11%) remained unchanged between 1991 and 1996. Furthermore, 97% of all VLBW infants and 99% of infants wei ghing <1000 g at birth had weights less than the 10th percentile at 36 week s' postmenstrual age. Mortality for 195 infants weighing 401 to 500 g was 89%, with nearly all su rvivors developing CLD. Mortality in infants weighing 501 to 600 g was 71%; among survivors, 62% had CLD, 35% had severe ICH, and 15% had proven NEC. Conclusions. Survival for infants between 501 and 1500 g at birth continued to improve, particularly for infants weighing <1000 g at birth. This impro vement in survival was not associated with an increase in major morbidities , because the incidence of CLD, proven NEC, and severe ICH did not change. However, poor postnatal growth remains a major concern, occurring in 99% of infants weighing <1000 g at birth. Mortality and major morbidity (CLD, sev ere ICH, and NEC) remain high for the smallest infants, particularly those weighing <600 g at birth.