Effects of very low birth weights on fetal and neonatal mortality rates in Alabama.

The relationship of births weighing less than 1,000 grams (g) to fetal and neonatal mortality rates, including changes over time, was studied. In Alabama during the period 1974-84, the percentage of reported births that weighed less than 500 g doubled, and the percentage of reported births weighing 500 to 999 g increased by about 10 percent. By the end of the study, while only 0.13 percent of reported births weighed less than 500 g, 24 percent of all stillbirths and 14 percent of all neonatal deaths were in this birth weight group. Similarly, in 1984, while only 0.62 percent of all births weighed 500 to 999 g, 23 percent of stillbirths and 42 percent of neonatal deaths were in this birth weight group. The data suggest that Alabama neonatal and fetal mortality rates declined more than was apparent in vital statistics data because of changes in reporting practices for very low birth weight newborns during the study period. Changes in vital statistics reporting are suggested to improve data reliability.