No Improvement in Outcome of Nationwide Extremely Low Birth Weight Infant Populations Between 1996–1997 and 1999–2000

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Abstract
OBJECTIVE. Our goal was to investigate whether outcome in extremely low birth weight infants changes over time in Finland. PATIENTS AND METHODS. All infants with a birth weight <1000 g born in Finland in 1996–1997 and 1999–2000 were included in the study. Perinatal and follow-up data were collected in a national extremely low birth weight infant research register. Data concerning cerebral palsy and visual impairment were obtained from hospitals, the national discharge, and visual impairment registers. RESULTS. A total of 529 and 511 extremely low birth weight infants were born during 1996–1997 and 1999–2000. No changes were detected in prenatal, perinatal, neonatal, and postneonatal mortality rates between the periods. The survival rates including stillborn infants were 40% and 44%. The incidence of respiratory distress syndrome and septicemia increased from 1996–1997 to 1999–2000 (75% vs 83% and 23% vs 31%). The overall incidence of intraventricular hemorrhage increased (29% vs 37%), but the incidence of intraventricular hemorrhage grades 3 through 4 did not (16% vs 17%). The rates of oxygen dependency at the age corresponding with 36 gestational weeks, retinopathy of prematurity stages 3 to 5, cerebral palsy, and severe visual impairment did not change. Mortality remained higher in 1 university hospital area during both periods compared with the other 4 areas, but no regional differences in morbidity were detected during the later period. CONCLUSIONS. No significant changes were detected in birth or mortality rate in extremely low birth weight infants born in Finland during the late 1990s, but some neonatal morbidities seemed to increase. Regional differences in mortality were detected in both cohorts. Repeated long-term follow-up studies on geographically defined very preterm infant cohorts are needed for establishing reliable outcome data of current perinatal care. Regional differences warrant thorough audits to assess causalities.