Racial disparities in preterm births and fetal losses

Project Summary (30 lines)
Preterm birth (<37 weeks of gestation) increases the risk infant death, hospitalization, developmental
disorders, and low educational attainment. Although non-Hispanic (NH) Black mothers show an increased
risk (vs. NH whites) of delivering preterm, NH Black infants historically show―at each gestational age
before term―improved health and survival relative to NH white infants. The main explanation for this
counterintuitive finding assumes greater selection against frail NH Black fetuses. According to the selection
argument, excess fetal loss among frail NH Black gestations results in a hardier cohort of survivors to birth
but who are delivered preterm.
Prior work describing this racial survival advantage has three important limitations. First, it continues to
infer the survival advantage from data now nearly two decades old. Second, it includes no test of the fetal
selection argument. Third, it fails to utilize a structural racism framework to understand the potential causes
of, and changes over time and place in, racial differences in fetal loss and infant survival. Rapid changes in
neonatal technology suggest that decades-old estimates of the survival advantage may have, since 2000,
diminished―or even transformed into a disparity. We will use the universe of live births, infant deaths, and
fetal deaths among NH Blacks and NH whites in the US (~65 million records, 1995 to 2018) to rigorously
examine race-specific trends in preterm birth and infant mortality rates. We will link these records
longitudinally by conception cohort to achieve several research objectives.
First, we will determine whether NH Blacks (vs. NH whites) born preterm show a survival advantage—or a
disparity—in infant mortality in the US. Second, we will investigate how the NH Black / NH white difference
in preterm birth rates and infant mortality rates has changed over time, in response to fluctuations in fetal
death rates and exogenous changes in neonatal technology (e.g., use of antenatal steroids). Third, we will
use a structural racism theoretical framework to examine the extent to which dynamic race-based spatial
indicators of inequality (e.g., segregation, incarceration rates) affect patterns across place and time in NH
Black (vs. NH white) fetal loss, selection in utero, and infant mortality among preterm births.
Our work is significant because we focus on the entire spectrum of perinatal outcomes, including the often
neglected but quite large racial disparity in fetal death. Results are expected to advance the knowledge base
on NICHD's high-priority research area to better understand racial/ethnic differences in infant health. Our
approach will also inform our understanding of the extent to which structural racism may have maintained―or
exacerbated―perinatal health disparities. Lastly, our place-based analysis will identify regions with
potentially large disparities in fetal loss and perinatal survival that may benefit from targeted healthcare and
non-healthcare resources.

Grant Number: 5R01HD103736-05
NIH Institute/Center: NIH
Principal Investigator: Tim Bruckner