Does Race or Ethnicity Play a Role in the Origin, Pathophysiology, and Outcomes of Preeclampsia? An Expert Review of the Literature.

The burden of preeclampsia, a significant contributor to perinatal morbidity and mortality, is not born equally across the population. While the prevalence of preeclampsia has been reported to be 3-5%, racial and ethnic minority groups such as non-Hispanic Black women and American Indian/Alaskan Native women are widely reported to be disproportionately affected by preeclampsia. However, studies that add clarity to the causes of the racial and ethnic differences in preeclampsia are limited. Race is a social construct, often self-assigned, is variable across settings, and fails to account for subgroups. Studies of the genetic structure of human populations continue to find more variation within racial groups than between them. Efforts to examine the role of race and ethnicity in biomedical research should consider these limitations and not use it as a biological construct. Further, the use of race in decision-making in clinical settings, may worsen the disparity in health outcomes. Most of the existing disparities data examines the differences between White and non-Hispanic Black women. Fewer studies have enough sample size to evaluate outcomes in the Asian, American Indian/Alaska Native, or mixed-race women. Racial differences are noted in the occurrence, presentation, and short term and long-term outcomes of preeclampsia. Well-established clinical risk factors for preeclampsia such as obesity, diabetes, and chronic hypertension disproportionately affect non-Hispanic Black, American Indian/Alaskan Native and Hispanic populations. However, with comparable clinical risk factors for preeclampsia, among women of different race or ethnic groups, addressing modifiable risk factors has not been found to have the same protective effect for all women. Abnormalities of placental formation and development, immunologic factors, vascular changes, and inflammation have all be identified as contributing to the pathophysiology of preeclampsia. Few studies have examined race and the pathophysiology of preeclampsia. Despite attempts, a genetic basis for disease has not been identified. A number of genetic variants, including APOL1, have been identified as possible risk modifiers. Few studies have examined race and prevention of preeclampsia. Although low dose aspirin for the prevention of preeclampsia is recommended by the US Preventive Service Task Force, a population based study found racial/ethnic differences in preeclampsia recurrence after implementation of low dose aspirin supplementation. After implementation, recurrent preeclampsia reduced among Hispanic women (76.4% vs. 49.6%; p <.0001), but there was no difference in recurrent preeclampsia in non-Hispanic Black women, (13.7 vs. 18.1, p=0.252). Future research incorporating the National Institute on Minority Health and Health Disparities (NIMHD) Multilevel Framework, specifically examining the role of racism on the burden of disease, may help in the quest for effective strategies to reduce the disproportionate burden of preeclampsia on a minority population. In this model, a multilevel approach provides a more comprehensive approach and takes into account the influence of behavioral factors, environmental factors, and healthcare systems, not just on the individual.