Racial and ethnic disparities in environmental chemical exposures and hypertensive disorders of pregnancy: The ECHO-wide cohort study.

Hypertensive disorders of pregnancy (HDP) are a leading cause of maternal and infant mortality and morbidity worldwide. This prospective cohort study investigated the association of racial and ethnic disparities in HDP and explored the potential mediation effect of environmental chemical exposures on excess HDP risk among non-Hispanic Black pregnant people. A total of 3,279 pregnant people were included from 11 cohorts across the United States in the Environmental influences on Child Health Outcomes (ECHO) Program. We analyzed 20 environmental chemicals detected in over 70 % of biospecimens collected during pregnancy. Among Hispanic, non-Hispanic White, and non-Hispanic Black participants, 11.8 %, 10.8 %, and 16.6 % were diagnosed with HDP, respectively. Compared with non-Hispanic White participants, non-Hispanic Black participants had a higher risk of HDP (aRR = 1.48; 95 % CI 1.13-1.94) and higher levels of traditional phthalate metabolites, but lower levels of phthalate alternative metabolites and perfluorooctanoic acid. Hispanic participants had a lower risk of gestational hypertension (aRR = 0.62; 95 % CI 0.40-0.98) and lower levels of perfluoroalkyl substances than non-Hispanic White participants. Critically, despite these race/ethnicity-specific exposure patterns, individual chemical exposures did not mediate the association between racial/ethnic group and HDP. These findings highlight the need to investigate cumulative chemical mixtures and non-chemical environmental and social determinants as potential drivers of HDP disparities.