Abstract
OBJECTIVES: This study examined changes in the reporting of very low-birthweight infants in Alabama from 1974 to 1994 and the impact on perinatal mortality rates. METHODS: Linked live birth, neonatal death, and stillbirth records of infants born weighing less than 1500 g were compared. RESULTS: The changes in mortality over time ranged from a drop from 100% to 92% in the under-500-g group to a drop from 39% to 4% in the 1000-to 1499-g group. The percentage of total births weighing less than 500 g increased by 155%; the percentage of 1000- to 1499-g births increased by only 7%. As a result, the percentage of neonatal mortality attributable to live births below 500 g increased from 3% to 32%. CONCLUSIONS: Increased reporting of births below 500 g has masked improvements in neonatal mortality.