Abstract 1452 Poster Session III, Monday, 5/3 (poster 36)

In three separate reports, we have examined the outcome of extremely low birthweight infants (ELBW) weighing less than 800 grams admitted to the University of Washington NICU in Seattle. In these studies, neonatal mortality declined from 80% (1977-1980) to 64% (1983-1985) to 50% (1986-1990) with no significant difference in the prevalence of major neurosensory disabilities. In this fourth cohort (1991-1995) we further examine the mortality and morbidity of this unique population and describe ELBW outcome trends over a near twenty year period.

From 1991 to 1995, a total of 208 newborns weighing less than 800 grams were admitted to the University of Washington NICU, compared to 206 between 1986-1990. 97 (47%) survived to discharge compared to 104 (50%) between 1986-1990. Mean birth weight of the survivors was 705 grams (499-798). Mean gestational age was 25 weeks (23-31). Birth weight subgroup survival was: 700-799 grams (66%), 600-699 grams (53%), 500-599 grams (19%). 74 (76%) of the surviving infants were followed longitudinally monitoring growth, vision and hearing, neurologic status and developmental function. The mean corrected age at follow-up was 23 months (12-72). Major neurosensory disabilities were identified in 8/74 (11%), which is significantly less than the 1986-1990 cohort 17/72 (23%) (p = .04). The mean mental and motor developmental scores of our current cohort are 93 (50-124) and 90 (50-131) with no difference between the birth weight subgroups and no difference when compared to the 1986-1990 cohort.

Survivorship of infants weighing < 800 grams increased approximately 15% per time period in the three previous studies from our NICU, with no change in major neurosensory disability. In our current cohort NICU admissions and survivorship are unchanged from the 1986-1990 cohort, while major morbidity significantly decreased. Survivorship in all four cohorts continues to favor females, and female survivors have fewer major neurosensory disability. Early outcome of recently born ELBW infants appears acceptable.