Determinants of the neonatal mortality.

A recent sharp decline in the neonatal mortality in our medical center prompted a critical analysis of viral statistics of the newborn service during the years 1966 through 1973. The mean neonatal mortality for the entire period was 15.4 per 1,000 live births, and 11.0 in the period 1972 through 1973. The annual neonatal mortalities bore a direct relationship to the annual incidences of infants with birth weights of 1,500 gm or less. The reduction in the proportion of infants in the latter weight group during 1972 through 1973 accounted for three quarters of the improvement in the neonatal mortality as compared to that of the previous years. One quarter of the improvement could be attributable to a decrease in mortality that occurred only in infants in the latter weight group during the same period.