Contribution of previable births to infant mortality rate racial disparity in the United States

Objectiveto quantify racial differences in contribution of previable live births (<20 weeks gestational age (ga)) to united states (us) infant mortality rates (imr).methodspopulation-based retrospective cohort of us live births (2007–14) using cdc wonder database stratified by maternal race/ethnicity. we compared the contribution of previable births to imr and calculated modified imrs (≥20 weeks ga) excluding previable live births in each group. contingency tables and chi-square calculations were performed to detect differences between groups.resultspreviable deaths represented 4.1%, 7.7%, and 5.0% of total deaths for nonhispanic white, nonhispanic black, and hispanic, respectively. previable contribution to total imr are 0.21, 0.89, and 0.26 per 1000 live births (p < 0.0001). modified imrs are 4.98, 10.85, and 4.69 deaths per 1000 live births.conclusionimr standardization with a minimum ga may obscure the disproportionate contribution of previable births to imrs among the black population, which has the largest proportion of previable births.