THE SWEDISH NATIONAL PROSPECTIVE-STUDY ON EXTREMELY LOW-BIRTH-WEIGHT (ELBW) INFANTS - INCIDENCE, MORTALITY, MORBIDITY AND SURVIVAL IN RELATION TO LEVEL OF CARE

In a 2-year (1990-92) prospective national investigation, comprising a ll stillborn and live-born ELBW infants with a birthweight of less tha n or equal to 1000 g born at 23 completed weeks of gestation or more, we examined the incidence, neonatal mortality, major morbidity and inf ant survival in relation to level of care and place of residence. A to tal of 633 ELBW infants were live-born, i.e. 0.26% of all live-born in fants, and 298 were stillborn. The average neonatal mortality was 37% and 91% at 23 weeks, 70% at 24 weeks, and 40% at 25 weeks of gestation . Of neonatal survivors, 8% had intraventricular haemorrhage grade 3, 10% retinopathy of prematurity of stage greater than or equal to 3, 2% necrotizing enterocolitis, and 28% were oxygen-dependent at a time co rresponding to 36 weeks of gestation. In all, 77% were treated with me chanical ventilation, whereas 19% survived without, almost all of them being CPAP treated. Infant mortality among infants born at level III (tertiary centres) was 30%, at level IIa (with full perinatal service) 46% and at level IIb (with basic neonatal service) 55%. Only 1% was b orn at hospital level I. Regarding the relation to place of residence, the mortality rates among infants residing in the areas served by lev els III, IIa and IIb hospitals were 36%, 45% and 41%, respectively. Th e referral system thus functioned well, but can be improved, and incre ased perinatal referral, at borderline perinatal viability, might prov ide a better quality of care and a better chance of survival.