Cardiovascular impact on risk of preeclampsia, -an epidemiologic cohort study

Abstract Introduction Preeclampsia complicates 3-5% of pregnancies worldwide and accounts for approximately 45 000 maternal deaths yearly. Preeclampsia is defined as new onset hypertension with organ dysfunction after 20 weeks’ gestation. Preeclampsia and cardiovascular disease have common risk factors such as chronic hypertension, obesity, and diabetes. In addition, preeclampsia is an independent risk factor for later cardiovascular disease. Preeclampsia might result from maladaptation of the cardiovascular system to pregnancy, but it is not known if other cardiac diagnoses are also risk factors for developing preeclampsia. Purpose The aim of this study was to evaluate the impact of heart failure and other cardiovascular disease on the risk of developing preeclampsia. Methods This was a registry-based case-control study using data form Swedish national registers including the medical birth register, national patient register and the LISA register. For every case with preeclampsia (90 354 pregnancies) five controls were chosen (Figure 1). Controls were matched to cases on mother’s year of birth. A sub-analysis investigated the risk for preterm preeclampsia (delivery <37 gestational weeks) by risk-factor. Potential cardiac risk factors were congenital heart disease, pulmonary hypertension, aortic/peripheral artery disease, valvular heart disease, myocardial infarction, other coronary artery disease, arrythmia, hypertension, myocarditis/pericarditis. Also known cardiometabolic risk factors were analyzed. All diagnoses were defined by ICD-9 and ICD-10 codes. We used multiple logistic regression analysis adjusted for confounders (BMI, age, smoking, assisted reproductive technology, parity, multifetal pregnancy, and comorbidities before pregnancy). Results Women with preeclampsia were more often obese, less often nulliparous and had more often multifetal pregnancies compared with women with normotensive pregnancies. Heart failure, valvular heart disease, hypertension, and diabetes (type 1+2) were independent risk factors for preeclampsia (Figure 2). Women with heart failure (n=273) had an adjusted odds ratio (aOR) of 2.09 (95% confidence interval (CI) 1.58-2.75) for developing any preeclampsia and an aOR of 2.90 (95% CI 1.82-4.61) for developing preterm preeclampsia. For women with valvular heart disease (n=424), the aOR was 1.50 (95% CI 1.17-1.92) for any preeclampsia and 2.55 (1.62-4.01) for preterm preeclampsia. The remaining seven cardiac diseases were not independent risk factors for preeclampsia. Conclusion Women with heart failure and valvular heart disease are at increased risk of developing preeclampsia. This association was particularly strong in women with preterm preeclampsia. Our results support the theory of preeclampsia as a stress test for cardiovascular disease. Although a rare patient group, these women have to be monitored closely during pregnancy, both for cardiac complications and for development of preeclampsia.Figure 1.Flow chart.Figure 2.Results.