title: Outcome of extremely low birth weight infants (500 to 999 grams) over a 12-year period.
abstract: OBJECTIVE
  Advances in neonatology have contributed to improved survival for extremely low birth weight (ELBW) infants. Neurodevelopmental outcome is usually reported for a single large group of infants rather than according to smaller birth weight groups because of small numbers. Our purpose was to review the neurodevelopmental outcome of a large group of ELBW infants and examine differential outcome according to birth weight.
  
  
  METHODS
  A total of 446 infants born between 1979 and 1991, with a birth weight of 500 to 999 g, were followed to mean age 55 months +/- 33 standard deviation. Univariate analyses of medical risk factors of birth weight, gestational age, year of birth, growth retardation, gender, inborn/outborn status, days on oxygen, intracranial hemorrhage, and social risk in relation to outcome were conducted on the group as a whole. Neurologic/developmental outcome was also analyzed by 100-g weight groups.
  
  
  RESULTS
  A total of 61% of all infants were completely normal, with no neurologic, neurosensory, or cognitive deficits. There was no association between outcome and birth weight. There was a strong association between intracranial hemorrhage (ICH) grade III or IV and/or cystic periventricular leukomalacia (PVL) and abnormal outcome (Somers' D = .17) and ICH III/IV and/or cystic PVL and cognitive outcome (Kendall's tau = .15). Mild to moderate cognitive delays were associated with chronic lung disease (oxygen >60 days) (Kruskal-Wallis chi2 = 17.53) or high social risk (Kruskal-Wallis chi2 = 22.17).
  
  
  CONCLUSIONS
  In this study of ELBW infants, low birth weight was not associated with abnormal outcome. The risk factors of ICH III-IV/cystic PVL, chronic lung disease, and high social risk were associated with abnormal outcome.
authors.affiliation: Department of Pediatrics, University of California, San Francisco, San Francisco, California 94143, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Piecuch
authors.forename: C H
authors.initials: CH
authors.lastname: Leonard
authors.forename: B A
authors.initials: BA
authors.lastname: Cooper
authors.forename: S A
authors.initials: SA
authors.lastname: Sehring
mesh_terms: D000704:Analysis of Variance; D001724:Birth Weight; D002543:Cerebral Hemorrhage; D002657:Child Development; D003071:Cognition; D002658:Developmental Disabilities / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D007360:Intelligence; D007969:Leukomalacia, Periventricular; D008297:Male; D010102:Oxygen Inhalation Therapy; D012307:Risk Factors; D012959:Socioeconomic Factors