1. Women with a history of hypertensive disorders of pregnancy have a small but significant increased risk of developing cardiomyopathy in the peri-partum period
2. This increased risk of cardiomyopathy persisted for more than five years after the most recent pregnancy
Evidence Rating Level: 2 (Good)
Study Rundown: It is known that women with preeclampsia are at greater risk of developing cardiomyopathy in the peri-partum period (within 5 months of delivery), which may lead to severe complications including heart failure. However, the risk of developing cardiomyopathy in women with a history of other hypertensive disorders of pregnancy (HDP) beyond this period is not known. This retrospective study compared the rates of cardiomyopathy in women with a history of HDP to those who were normotensive during their pregnancies. There was a significantly higher hazard ratio for cardiomyopathy in the HDP group compared to the normotensive group, despite adjustments for factors such as age, diabetes, and smoking. This significance did not diminish even at five years of follow-up after the most recent pregnancy. While this study utilized tight protocols to rule-in patients with HDP and identify cases of cardiomyopathy, it may be limited by clinical difficulties in recognizing pre-gestational hypertension (an exclusion criteria) and asymptomatic cardiomyopathy. Overall, the study provides good evidence that warrants further research to confirm the link between hypertensive disorders of pregnancy and the risk of cardiomyopathy in pregnant women beyond the peri-partum period.
In-Depth [retrospective cohort]: This study aimed to quantify the risk of cardiomyopathy in two groups of pregnant women, either deemed “normotensive” or as having a “hypertensive disorder of pregnancy” (HBP). The primary outcome measure was cardiomyopathy events after the peri-partum period. This study also collected information regarding known confounders (age, smoking, multiple pregnancies) and potential confounders (post-pregnancy diabetes, hypertension, heart disease, obesity), and adjusted its analysis accordingly. After exclusion criteria were applied, 2 067 633 pregnancies were monitored during the study period. Of these, 76 108 pregnancies were complicated by HBP. Compared to women with normotensive pregnancies (18 211 603 person-years of follow-up, N = 1408 cardiomyopathy events, 7.7/100 000 person-years, 95%CI 7.3-8.2), women with HBP had a statistically significant increase in their risk of cardiomyopathy (173 062 person-years of follow-up, N=27 cardiomyopathy events; 15.6/100 000 person-years, 95%CI 10.7-22.7). Comparing rates of cardiomyopathy between women with history of HDP versus women who were normotensive during pregnancy yielded hazard ratios of 2.20 (95%CI 1.50-3.23) for severe preeclampsia, 1.89 (95%CI 1.55-2.32) for moderate preeclampsia, and 2.06 (95%CI 1.50-2.82) for gestational hypertension. Significant hazard ratios were still present for each condition at five years after the most recent pregnancy.
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