are rates really declining among non-Hispanic African Americans across the United States?
Vahratian A; Buekens P; Alexander GR Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI 48109, USA. amv@med.umich.edu OBJECTIVES: This study sought to examine state-specific trends in preterm delivery rates among non-Hispanic African Americans and to assess whether these rates are influenced by misclassification of gestational age. METHODS: The sample population consisted of singleton non-Hispanic White and non-Hispanic African-American infants born in 1991 and 2001 to U.S. resident mothers. For both time periods, state-specific and national preterm delivery rates were calculated for all infants, stratified by infant race/ethnicity. Next, birth-weight distributions within strata of gestational age were studied to explore possible misclassifications of gestational age. Lastly, state-specific and national preterm delivery rates among infants who weighed less than 2,500 g were separately computed. RESULTS: National analyses showed that the frequency of preterm
