Decline in neonatal mortality 1968 to 1977: better babies or better care?

The decline in neonatal mortality in North Carolina over the period 1968 to 1977 is examined in order to "determine how much of the decrease resulted from improved risk characteristics in the newborn population. A shift was found over time mostly among white births toward higher birth weights and longer gestations. Overall there was a 19% reduction in the low-birth-weight rate. Considerable improvement in birth weight-specific mortality was also found especially in babies weighing 1000 to 2500 g during the last 5 years of the study." The authors apply a neonatal risk matrix model to the changes over time and estimate that 34 percent of this mortality decrease was attributable to changes in the birth weight and gestational age makeup of the newborn population. (EXCERPT)