Women with a history of hypertensive disorders of pregnancy have a small but statistically significant increased risk of cardiomyopathy more than 5 months after delivery, according to a study appearing in the March 8 issue of JAMA.
Hypertensive disorders of pregnancy (HDP), which include preeclampsia and gestational hypertension, occur in up to 10 percent of pregnancies worldwide. In severe cases, preeclampsia can lead to multiple organ failure, seizures (eclampsia), and fetal and maternal death. Women with preeclampsia have a greatly increased risk of cardiomyopathy in the peripartum period (the last month of pregnancy until 5 months after delivery). Peripartum cardiomyopathy is often characterized by severely reduced myocardial contractility and symptoms of heart failure. Whether hypertensive disorders of pregnancy are also associated with cardiomyopathy later in life has not been known.
Ida Behrens, M.D., of Statens Serum Institut, Copenhagen, Denmark, and colleagues conducted a study that included 1,075,763 women with at least 1 pregnancy ending in live birth or stillbirth in Denmark, 1978-2012. These women had 2,067,633 eligible pregnancies during the study period, 76,108 of which were complicated by a hypertensive disorder of pregnancy (severe or moderate preeclampsia or gestational hypertension). During follow-up, 1,577 women (average age, 48.5 years at cardiomyopathy diagnosis) developed cardiomyopathy.
Compared with women without hypertensive disorders of pregnancy, women with a history of these disorders had significantly increased rates of cardiomyopathy, regardless of HDP severity, and these increases persisted more than 5 years after the latest pregnancy. This increase in risk appeared to be independent of ischemic heart disease, the risk of which is increased among women with a history of preeclampsia, and approximately 50 percent of the risk was not associated with postgestational hypertension. In this cohort, 11 percent of all cardiomyopathy events occurred in women with a history of hypertensive disorders of pregnancy.
The authors note that cardiomyopathy events are rare, even among women in this study with a history of HDP. "Accordingly, even though there was an association between HDP and increased risk of cardiomyopathy, the absolute risk was small."
"Further research is necessary to understand whether there is a causal mechanism behind this association."