Impact of very low birthweight on the black-white infant mortality gap.

In recent years, the rate of decline for the black infant mortality risk (IMR) has been slower than that for whites. The resultant widening in the black-white infant mortality gap has been accompanied by an increased percentage of very low birthweight (VLBW) infants (227 g-1,499 g) among black live births. Restricting our analysis to non-Hispanic black and white single live births, we used the 1983 national linked birth-death file to assess the relative contribution of VLBW infants to the black-white gap in IMR. VLBW occurred among 2.3% of all black live births and among 0.8% of all white live births. Deaths among VLBW infants accounted for 62.5% of the black-white gap in IMR. Although VLBW newborns represent a fraction of all live births in the United States, they account for almost two-thirds of the black-white gap in IMR. Since preterm delivery is associated with most VLBW infant deaths, our findings indicate the crucial need to identify strategies that reduce preterm births, among blacks in particular, to reduce significantly the infant mortality gap in the United States.