Cardiovascular Risk Factors Mediate the Long-Term Maternal Risk Associated With Hypertensive Disorders of Pregnancy

BACKGROUND: Hypertensive disorders of pregnancy (HDP), including gestational hypertension and preeclampsia, are associated with an increased risk of CVD. OBJECTIVES: The purpose of this study was to evaluate associations between HDP and long-term CVD and identify the proportion of the association mediated by established CVD risk factors. METHODS: Parous participants without CVD in the Nurses' Health Study II (n = 60,379) were followed for incident CVD from first birth through 2017. Cox proportional hazards models estimated HRs and 95% CIs for the relationship between HDP and CVD, adjusting for potential confounders, including prepregnancy body mass index, smoking, and parental history of CVD. To evaluate the proportion of the association jointly accounted for by chronic hypertension, hypercholesterolemia, type 2 diabetes, and changes in body mass index, we used the difference method. RESULTS: Women with HDP in first pregnancy had a 63% higher rate of CVD (95% CI: 1.37-1.94) compared with women with normotensive pregnancies. This association was mediated by established CVD risk factors (proportion mediated = 64%). The increased rate of CVD was higher for preeclampsia (HR: 1.72; 95% CI: 1.42-2.10) than gestational hypertension (HR: 1.41; 95% CI: 1.03-1.93). Established CVD risk factors accounted for 57% of the increased rate of CVD for preeclampsia but 84% for gestational hypertension (both P < 0.0001). CONCLUSIONS: Established CVD risk factors arising after pregnancy explained most (84%) of the increased risk of CVD conferred by gestational hypertension and 57% of the risk among women with preeclampsia. Screening for chronic hypertension, hypercholesterolemia, type 2 diabetes, and overweight/obesity after pregnancy may be especially helpful in CVD prevention among women with a history of HDP.