Trends in preterm birth and neonatal mortality among blacks and whites in the United States from 1989 to 1997

Preterm birth, a major determinant of infant mortality, has been increasing in recent years. The authors examined trends in preterm birth and its dete rminants by using the US birth and infant death files for 1989-1997. The im pact of trends in preterm birth rates on neonatal and infant mortality was also evaluated. Among Whites, preterm births (<37 completed weeks of gestat ion) increased from 8.8% of livebirths in 1989 to 10.2% in 1997, a relative increase of 15.6%. On the other hand, preterm births among Blacks decrease d by 7.6% (from 19.0% to 17.5%) during the same period. An increase in obst etric interventions contributed to increases in preterm births for both rac es but was outweighed by other unidentified favorable influences for Blacks . Neonatal mortality among preterm Whites dropped 34% during the 8 years of the study, while the decrease was only 24% among Blacks. This large dispar ity countered the changes in preterm birth rates so that the percentage dec line in neonatal mortality was similar in the two racial groups (18-20%). I n conclusion, the anticipated mortality benefit from a lower preterm birth rate for Blacks has been blunted by suboptimal improvement in mortality amo ng the remaining preterm infants. The widening race gap in mortality among preterm infants merits attention.