Abstract Body (Do not enter title and authors here): Background
Cardiovascular disease (CVD) is the leading cause of death among women in the US. Adverse pregnancy outcomes, particularly hypertensive disorders of pregnancy (HDP), are increasingly recognized as indicators of future CVD risk. Studies in diverse populations, especially those most affected by maternal morbidity and mortality, are urgently needed to direct guidelines and policy in the US.

Objectives
To determine the association between HDP and incident CVD in a diverse, real-world population; assess mediation by postpartum cardiometabolic conditions; and identify sociodemographic and structural correlates of incident postpartum hypertension.

Methods
We used linked electronic health record and survey data from the All of Us Research Program. Pregnancy episodes were identified using a validated algorithm. Cox regression and causal mediation models were used to estimate associations overall and stratified by the presence of pre-pregnancy cardiometabolic conditions (i.e., hypertension, obesity, diabetes, hyperlipidemia, and chronic kidney disease). Logistic regression was used to assess correlates of incident postpartum hypertension.

Results
Participants (n = 17,673) had a mean age of 30 years [IQR: 25, 35] years; 16% identified as Black, 42% as Hispanic, 35% reported a family income < $25,000, and 38% had < high school education. HDP was present in 12% of pregnancies. Over a median follow-up of 4.6 years, 724 women developed incident CVD. HDP was associated with a higher incidence of CVD (12.5 vs. 7.1 per 1,000 person-years; HR 1.85, 95% CI 1.51-2.26) (Figure 1A-1B). Among women without pre-pregnancy cardiometabolic conditions, the associations were stronger. However, the absolute CVD incidence was highest among women with pre-pregnancy cardiometabolic conditions regardless of HDP status (Figure 1B-1C). Incident postpartum hypertension mediated 87% (95% CI: 45, 100) of the association between HDP and CVD. Low income, rurality, and barriers to care, such as transportation and caregiving were associated with higher odds of incident postpartum hypertension (Figure 1D).

Conclusion
HDP is a significant early-life marker of premature CVD risk, especially among women without pre-pregnancy cardiometabolic conditions. Interventions that target cardiometabolic health before pregnancy and improve postpartum hypertension management, particularly among underserved populations, represent critical opportunities for CVD prevention across the life course.