Survival, cranial ultrasound and cerebral palsy in very low birthweight infants: 1980s versus 1990s

Abstract

OBJECTIVE: To determine the changes in the rates of survival, cranial ultrasound abnormalities and cerebral palsy in very low birthweight (VLBW) (birthweight 500-1499 g) infants between the early 1980s and the early 1990s. METHODOLOGY: A cohort study of consecutive VLBW live births in one tertiary perinatal hospital during two distinct eras was performed at The Royal Women's Hospital, Melbourne, a level-III perinatal centre. Consecutive VLBW infants born over the 18-month period from 1 October 1980 (n = 222), and over the 12-month period from 1 January 1992 (n = 202) were identified. The main outcome measures were the proportions of live births surviving to 5 years of age, rates of cranial ultrasound abnormalities, and rates of cerebral palsy at 5 years of age. RESULTS: Over the 18 months from 1 October 1980, 68% (150/222) VLBW live births survived to 5 years of age. The survival rate rose substantially to 82% (165/202) during 1992 (odds ratio 2.1, 95% confidence interval 1.4-3.2). The survival rate increased over time more for those of 500-999 g birthweight than for those of 1000-1499 g birthweight. The rates of cerebroventricular haemorrhage (CVH) were similar inlive births and survivors from both eras, as were the rates of cerebral palsy (7.5% in 1980-82; 7.8% in 1992) in survivors seen at 5 years of age. The positive predictive value of CVH for cerebral palsy was low, but cystic periventricular leucomalacia was followed by cerebral palsy in seven of eight survivors from the 1992 cohort. CONCLUSIONS: Despite the increasing survival rate with improvements in perinatal care, including more antenatal steroid therapy and the introduction of exogenous surfactant, the rates of CVH and of cerebral palsy in survivors have not diminished.