Improving outcome for Western Australian infants with birthweights 500-999 g

To assess changes in survival and disability in liveborn extremely low birthweight infants (500-999 g) in Western Australia, 1980-1987.

Cohort study comparing two periods, 1980-1983 (P1) and 1984-1987 (P2).

All 586 liveborn extremely low birthweight infants in WA in 1980-1987 (266 in P1, 320 in P2).

Birthweight, place of birth, age at death, neurosensory examination findings and scores on the Griffiths Mental Development Scales or other standardised test results.

482/586 infants (82%) were born at King Edward Memorial Hospital (KEMH), a level III referral centre, and a further 4% were transferred there after birth. The proportion born at KEMH increased from 78% in P1 to 86% in P2. Survival increased from 35% to 43% overall. In those below 800 g birthweight, survival doubled from 14% to 29%. There was no change in the age at death for non-survivors. Follow-up information was known for 222 of the 229 survivors at median ages of 46 months (P1) and 43 months (P2). Disability rates in infants below 800 g birthweight remained static (P1, 26%; P2, 28%), but fell in those of 800-999 g birthweight from 24% to 13%. Overall, survival free of disability increased from 26% to 34%.

Increased survival rates occurred without any increase in the rate or severity of disability in survivors.