Impact of preterm birth on racial disparities in infant mortality attributable to birth defects — United States, 2003–2005

Birth defects are a leading cause of infant mortality in the United States. Reports using data through 2002 have highlighted disparities in overall infant mortality and infant mortality attributable to birth defects (IMBD) between non-Hispanic black and non-Hispanic white infants. Black-white disparities in preterm birth have also been reported, and rates of preterm birth have steadily increased in recent years. We estimated the rate of IMBD overall, and by preterm birth and race, using the period linked birth/infant death data for US residents for January 2003 to December 2005. IMBD occurred in 1.4 per 1,000 live births. We found that 1) the overall black-white racial disparity in IMBD has not narrowed; 2) among term infants (born ³37 weeks gestation), blacks had significantly higher IMBD than whites; but 3) there was no significant racial difference in IMBD among early or late preterm infants (born <34 or 34–36 weeks gestation, respectively). Based on this analysis, the black-white racial disparity in IMBD cannot be explained by differences in preterm birth. Although the IMBD rate is decreasing over time, the reasons why term white infants with birth defects fare better than term black infants with birth defects are unclear and will only be understood through further investigation, which should include an assessment of differential access to prenatal care and/or prenatal ascertainment of birth defects.