Introduction: Hypertensive disorders of pregnancy (HDP) and pre-pregnancy hypertension are associated with increased maternal morbidity and mortality, and information on racial/ethnic disparities is lacking. The association of HDP and pre-pregnancy hypertension with incident maternal embolism was examined within five years of delivery and for the study period (≤14 years) overall and by race/ethnicity. Methods: Women with a live, singleton birth in South Carolina (2004-2016) aged 12-49 years were included in a retrospective cohort study (n=433,625; non-Hispanic white [NHW; 58.7%], non-Hispanic black [NHB; 31.8%)] and Hispanic [9.5%]). HDP were defined by hospitalization/emergency department (ED) visit data (pre-eclampsia, eclampsia, gestational hypertension) or birth certificates (gestational hypertension). Pre-pregnancy hypertension was also defined by these data sources. Hospitalization/ED visit data and death certificates defined fatal and non-fatal incident embolism. Cox proportional hazards models were used with covariate adjustment. Results: In women with ≥1 pregnancy, 81.6% never experienced pre-pregnancy hypertension or HDP, 0.4% had pre-pregnancy hypertension without superimposed HDP, 15.7% had HDP alone, and 2.3% had pre-pregnancy hypertension with superimposed HDP. Incident embolism risk was elevated ≤14 years after delivery for women with HDP alone (HR=1.21, 95% CI: 1.12-1.30) and with pre-pregnancy hypertension with superimposed HDP (HR=1.44, 95% CI: 1.26-1.65) compared to neither condition. Pre-pregnancy hypertension alone was not associated with incident embolism risk (HR=1.23, 95% CI: 0.84-1.80). The table shows the joint impact of racial/ethnicity and the exposure categories. Discussion: Fatal and non-fatal embolism up to 14 years after delivery was increased for HDP regardless of pre-pregnancy hypertension suggesting a long-term impact. Incident embolism event rates were highest for NHB women and lowest for Hispanic women across all HDP exposure categories.
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