Hypertensive Disorders of Pregnancy Subtypes and Long-Term Cardiovascular Risk

Importance: Hypertensive disorders of pregnancy (HDPs) are associated with an increased long-term risk of cardiovascular disease, but the risks across different HDP subtypes, particularly those other than preeclampsia, remain unclear. Objective: To examine whether the risk and distribution of specific cardiovascular outcomes differ across HDP subtypes. Design, Setting, and Participants: This nationwide cohort study retrospectively analyzed women with deliveries in South Korea from 2010 to 2018 using the National Health Insurance Service database. HDPs were classified into 5 subtypes: chronic hypertension, gestational hypertension, superimposed preeclampsia, preeclampsia/eclampsia, and unspecified hypertension. Events were verified through December 2022. Data were analyzed from June 1 to October 31, 2025. Exposures: HDPs and their subtypes. Main Outcomes and Measures: The primary outcome was a composite of cardiovascular events, including cardiovascular death, heart failure, myocardial infarction, stroke, and atrial fibrillation. Adjusted hazard ratios (AHRs) were estimated using Cox models accounting for age, cardiovascular comorbidities, demographic, lifestyle, and pregnancy-related factors. Results: Among 570 843 women (mean [SD] age, 32.7 [4.0] years), 22 876 (4.0%) had HDPs. HDPs were associated with a higher incidence of cardiovascular events compared with women without HDPs (AHR, 1.62; 95% CI, 1.49-1.76; P < .001). The absolute risk increase was approximately 2.10 additional cardiovascular events per 1000 person-years over a median follow-up of 6.5 years (IQR, 4.7-8.7 years; incidence rate, 4.39 vs 2.29 per 1000 person-years). Among those with HDPs, 34.8% had gestational hypertension, 32.4% had preeclampsia or eclampsia, 17.7% had unspecified hypertension, 12.3% had chronic hypertension, and 2.8% had superimposed preeclampsia. All subtypes were independently associated with higher cardiovascular risk, with the highest risk observed in superimposed preeclampsia compared with women without HDPs (AHR, 2.93; 95% CI, 2.15-3.99; P < .001). All subtypes were associated with increased risks of heart failure and stroke, and most subtypes were associated with higher cardiovascular mortality. Unspecified hypertension was associated with myocardial infarction, and chronic hypertension and unspecified hypertension were associated with atrial fibrillation. Conclusions and Relevance: In this cohort study, all HDP subtypes were associated with modest increases in long-term cardiovascular risk, except superimposed preeclampsia, which was associated with a markedly higher risk. These findings suggest that women with superimposed preeclampsia may benefit from closer postpartum cardiovascular surveillance.