Abstract

AIMS To compare the survival and sensorineural disability rates in extremely low birthweight (ELBW) (500–999 g) infants born in 1991–2 with ELBW babies born in 1979–80 and 1985–7, and with normal birthweight infants born in the same time periods.

METHODS ELBW infants born in Victoria in 1991–2 were compared with regional cohorts of ELBW infants born in 1979–80 and 1985–7, and with contemporaneous normal birthweight (>2499 g) controls, and those of birthweight 500–749 g with those of birthweight 750–999 g.

RESULTS In 1979–80, 25.4% (89/351) ELBW live births survived to 2 years of age, increasing significantly to 37.9% (212/560) in 1985–7, and to 56.2% (241/429) in 1991–2. The rates of severe disability in survivors assessed were 12.4%, 6.6%, and 6.8% in the 1979–80, 1985–7, and 1991–2 ELBW cohorts, respectively. The rate of disability, overall, was significantly lower in the 1985–7 and 1991–2 ELBW cohorts compared with the 1979–80 ELBW cohort, but was significantly higher in 1991–2 ELBW infants than normal birthweight controls. Surviving children with birthweights <750 g had significantly higher rates of sensorineural disability compared with those of birthweight 750–999 g in 1979–80, but not in 1985–7 or 1991–2.

CONCLUSIONS Survival rates for ELBW babies in Victoria have progressively improved since the late 1970s. Sensorineural outcome for survivors born in 1985–7 has also improved compared with those born in 1979–80. However, there is no evidence that further reductions in adverse sensorineural outcomes into the 1990s, and these, as well as disabilities remain higher in ELBW than in normal birthweight babies.