521 - Racial differences in spatial social polarization and placental pathology: an exploratory study of preterm births in Chicago

While social and economic disadvantage is associated with racial disparities in preterm birth, the underlying biological mechanisms are poorly understood. Placental dysfunction, linked to preterm delivery, has been suggested as a marker of stress, and racial differences in placental inflammation and vascular malperfusion have been described. Recently, a novel measure of spatial social polarization, which quantifies the extremes of privilege and deprivation, has emerged as a useful metric for public health monitoring of birth outcomes.  No study to date has determined the relationship of spatial social polarization, preterm birth, and placental pathology.   

Objective:

To examine the association of spatial social polarization as measured by the Index of Concentration at the Extremes (ICE) with placental pathology among preterm births.

Design/Methods:

We conducted a five-year retrospective cohort study of preterm infants born at ≤34 weeks at Northwestern Prentice Women's Hospital in Chicago, Illinois. Placental pathology reports underwent standardized review and maternal addresses were geocoded to census tracts.  Poisson regression was performed to examine the relationship between placental pathology and ICE scores, adjusting for available relevant covariates.

Results:

Placentas were available for 349 white and 214 African American (AA) mother-infant pairs among births at ≤34 weeks’ gestation. Compared to infants born to white mothers, infants born to AA mothers were more likely to be born in lower birth weight and gestational age categories. Compared to those of white mothers, placentas of AA mothers had higher percentages of acute inflammation (42.5% vs 30.7%) and maternal vascular malperfusion (88.3% vs 81.4%) but lower percentages of fetal vascular pathology (28.5% vs 36.4%). After adjustment for relevant confounders, there were no statistically significant associations between ICE scores and any of the four placental pathology domains.

Conclusion(s):

This study supports other published evidence that race is associated with placental pathophysiology in preterm births. However, no significant associations between spatial social polarization, as measured by ICE, and placental histopathology domains were found after adjustment by relevant confounders. Placental histopathology may be useful for understanding the biological processes that shape disparities in pregnancy outcomes; however, more research in this domain is needed.