Outcome of infants weighing less than 800 grams at birth: 15 years' experience

Mortality and neurodevelopmental morbidity among infants weighing less than 800 g at birth are compared in three separate studies from the same intensive care nursery during an almost 15-year period.

The survival and neurodevelopmental outcome of 210 infants with birth weights less than 800 g admitted to the University of Washington neonatal intensive care unit between 1986 and 1990 are compared with those of two previous cohorts (1977 through 1980 and 1983 through 1985) of extremely low birth weight (ELBW) infants from the same nursery.

Annual admissions of these ELBW infants nearly doubled from 1977 to 1990, whereas nursery survival rose from 20% between 1977 and 1980, to 36% between 1983 and 1985, to 49% in this current study of births between 1986 and 1990. The greatest increase in survival among the three studies occurred among infants with birth weights less than 700 g. Female survival was 20% higher than male survival in each of the time periods. The prevalence of major neurosensory impairments did not differ significantly among the three study groups (19%, 21%, and 22% respectively); male survivors were more commonly affected across time periods. There were no differences in mean cognitive test scores between the current 1986 through 1990 birth cohort (94) and the two previous cohorts (1977 through 1980, 98; 1983 through 1985, 89).

The experience of our center with these ELBW infants over time seems reassuring to the extent that progressive increases in nursery survival have not resulted in increased neurodevelopmental morbidity.