Racial disparities in fetal and infant outcomes: a multiple-decrement life table approach

We discuss different frameworks to conceptualize age in the gestational period and in the first year of life, and then apply two conceptualizations to quantify racial/ethnic differences on a range of different fetal and infant outcomes in the United States. In particular, we focus on the extended approach, which combines gestational age and age in the first year of life onto a continuum of adjusted age since conception, and the gestational approach, which takes the viewpoint of gestation but considers both fetal outcomes and eventual outcomes in the first year of life. Both approaches use a multiple-decrement life table framework, accounting for decrements that related to all potential outcomes, including birth, fetal death, and infant death or survival. We find that the risks of both fetal and infant death are non-linear over the gestational age period and early weeks of life, with the highest risks at the beginning of the period (at 20 weeks) but also at around 37-40 weeks. The relative risks of different race/ethnic groups also change across age; in particular, the non-Hispanic Black population has a heightened risk of all adverse outcomes, but the magnitude of the difference in risk depends on gestational age, and in general, disparities are lowest in the mid-range of gestational ages.