OUTCOME OF EXTREMELY LOW-BIRTH-WEIGHT INFANTS (500 TO 999 GRAMS) OVERA 12-YEAR PERIOD

Objective. Advances in neonatology have contributed to improved surviv al for extremely low birth weight (ELBW) infants. Neurodevelopmental o utcome 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 bi rth weight. Study Design. 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 ri sk factors of birth weight, gestational age, year of birth, growth ret ardation, gender, inborn/outborn status, days on oxygen, intracranial hemorrhage, and social risk in relation to outcome were conducted on t he group as a whole. Neurologic/developmental outcome was also analyze d by 100-g weight groups. Results. A total of 61% of all infants were completely normal, with no neurologic, neurosensory, or cognitive defi cits. 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 abnorma l outcome (Somers' D = .17) and ICH III/IV and/or cystic PVL and cogni tive outcome (Kendall's tau = .15). Mild to moderate cognitive delays were associated with chronic lung disease (oxygen >60 days) (Kruskal-W allis chi(2) = 17.53) or high social risk (Kruskal-Wallis chi(2) = 22. 17). Conclusion. In this study of ELBW infants, low birth weight was n ot associated with abnormal outcome. The risk factors of ICH III-IV/cy stic PVL, chronic lung disease, and high social risk were associated w ith abnormal outcome.