Lethal congenital anomalies as a cause of birth-weight-specific neonatal mortality.

The percentage of neonatal mortality caused by lethal congenital anomalies and the distribution of specific anomalies in various birth-weight groups are presented. State vital statistics data and autopsy-confirmed data from a single hospital are compared. Of neonates who died, less than 5% who were born weighing between 500 and 999 g died of a congenital anomaly, and nearly 45% who were born weighing more than 2,500 g died of a congenital anomaly. Most deaths associated with congenital anomalies in infants born weighing more than 2,500 g are cardiac in origin. Twenty-three percent of all neonatal deaths in Alabama are attributed to a lethal congenital anomaly. Use of these data to define limits to future improvements in neonatal mortality by standard medical care is discussed.