Neurodevelopmental and functional outcomes of extremely low birth weight infants in the National Institute of Child Health and Human Development Neonatal Research Network, 1993-1994

Objectives. The purposes of this study were to report the neurodevelopmenta l, neurosensory, and functional outcomes of 1151 extremely low birth weight (401-1000 g) survivors cared for in the 12 participating centers of the Na tional Institute of Child Health and Human Development Neonatal Research Ne twork, and to identify medical, social, and environmental factors associate d with these outcomes. Study Design. A multicenter cohort study in which surviving extremely low b irth weight infants born in 1993 and 1994 underwent neurodevelopmental, neu rosensory, and functional assessment at 18 to 22 months' corrected age. Dat a regarding pregnancy and neonatal outcome were collected prospectively. So cioeconomic status and a detailed interim medical history were obtained at the time of the assessment. Logistic regression models were used to identif y maternal and neonatal risk factors for poor neurodevelopmental outcome. Results. Of the 1480 infants alive at 18 months of age, 1151 (78%) were eva luated. Study characteristics included a mean birth weight of 796 +/- 135 g , mean gestation (best obstetric dates) 26 +/- 2 weeks, and 47% male. Birth weight distributions of infants included 15 infants at 401 to 500 g; 94 at 501 to 600 g; 208 at 601 to 700 g; 237 at 701 to 800 g; 290 at 801 to 900 g; and 307 at 901 to 1000 g. Twenty-five percent of the children had an abn ormal neurologic examination, 37% had a Bayley II Mental Developmental Inde x <70, 29% had a Psychomotor Developmental Index <70, 9% had vision impairm ent, and 11% had hearing impairment. Neurologic, developmental, neurosensor y, and functional morbidities increased with decreasing birth weight. Facto rs significantly associated with increased neurodevelopmental morbidity inc luded chronic lung disease, grades 3 to 4 intraventricular hemorrhage/periv entricular leukomalacia, steroids for chronic lung disease, necrotizing ent erocolitis, and male gender. Factors significantly associated with decrease d morbidity included increased birth weight, female gender, higher maternal education, and white race. Conclusion. ELBW infants are at significant risk of neurologic abnormalitie s, developmental delays, and functional delays at 18 to 22 months' correcte d age.