Incidence and Long-Term Outcomes of Hypertensive Disorders of Pregnancy.

Background: Hypertensive disorders of pregnancy (HDP) are associated with increased risks for cardiovascular disease later in life. The HDP incidence is commonly assessed using diagnostic codes, which are not reliable; and typically are expressed per-pregnancy, which may underestimate the number of women with an HDP history after their reproductive years.

Objectives: This study sought to determine the incidence of HDP expressed as both per-pregnancy and per-woman, and to establish their associations with future chronic conditions and multimorbidity, a measure of accelerated aging, in a population-based cohort study.

Methods: Using the Rochester Epidemiology Project medical record-linkage system, the authors identified residents of Olmsted County, Minnesota, who delivered between 1976 and 1982. The authors classified pregnancies into normotensive, gestational hypertension, pre-eclampsia, eclampsia, pre-eclampsia superimposed on chronic hypertension, and chronic hypertension using a validated electronic algorithm, and calculated the incidence of HDP both per-pregnancy and per-woman. The risk of chronic conditions between women with versus those without a history of HDP (age and parity 1:2 matched) was quantified using the hazard ratio and corresponding 95% confidence interval estimated from a Cox model.

Results: Among 9,862 pregnancies, we identified 719 (7.3%) with HDP and 324 (3.3%) with pre-eclampsia. The incidence of HDP and pre-eclampsia doubled when assessed on a per-woman basis: 15.3% (281 of 1,839) and 7.5% (138 of 1,839), respectively. Women with a history of HDP were at increased risk for subsequent diagnoses of stroke (hazard ratio [HR]: 2.27; 95% confidence interval [CI]: 1.37 to 3.76), coronary artery disease (HR: 1.89; 95% CI: 1.26 to 2.82), cardiac arrhythmias (HR: 1.62; 95% CI: 1.28 to 2.05), chronic kidney disease (HR: 2.41; 95% CI: 1.54 to 3.78), and multimorbidity (HR: 1.25; 95% CI: 1.15 to 1.35).

Conclusions: The HDP population-based incidence expressed per-pregnancy underestimates the number of women affected by this condition during their reproductive years. A history of HDP confers significant increase in risks for future chronic conditions and multimorbidity.