Racial disparity in placental pathology in the collaborative perinatal project

There is substantial disparity in perinatal outcomes between white and African-American women, but the underlying biological mechanisms are poorly understood. The placenta is the principal metabolic, respiratory, excretory, and endocrine organ of the fetus. We studied the association between maternal race and types and severity of placental pathology.

Using data from the U.S. Collaborative Perinatal Project (1959-1966), we studied 32,295 African-American and white women with singleton births. CPP pathologists conducted detailed placental examinations following a standard protocol with quality control procedures. Logistic regression modeling was used to test the association between race and placental pathology adjusting for potential confounders.

Compared to white women, African-American women had a higher risk of fetal neutrophilic infiltration (adjusted odds ratio [aOR], 1.2; 95% confidence interval [CI], 1.0-1.4), and 1.5-fold higher risk of low placental weight (95% CI, 1.3-1.7). However, various placental vascular lesions were significantly less common in African-American women, including infarcts and thrombosis in the cut surface, villous infarcts in the intervillous space, emergence of stromal fibrosis and Langerhans layer in the terminal villi, old hemorrhage in the maternal surface, thrombosis in the intervillous space, and calcification throughout the cut surface (aOR ranging from 0.5 to 0.8). Similar patterns were observed in pregnancies with pregnancy associated hypertension, small-for-gestational-age, and preterm birth.

As compared with white women, African-American had higher prevalence of inflammatory lesions but lower prevalence of vascular lesions in placental pathology.