Hypertensive disorders in pregnancy may signal increased risk of cardiomyopathy

More than five months after delivery, women with a history of hypertensive disorders during pregnancy had a significantly increased risk of cardiomyopathy, according to an analysis of women in Denmark.

However, the researchers mentioned that cardiomyopathy remained rare even among women with a history of hypertensive disorders of pregnancy and noted that the absolute risk was small.

Lead researcher Ida Behrens, MD, of Statens Serum Institute in Copenhagen, and colleagues published their results online in JAMA on March 8.

The researchers mentioned that approximately 10 percent of pregnant women have hypertensive disorders of pregnancy such as preeclampsia and gestational hypertension during the second half of their pregnancy. They added that preeclampsia could lead to multiple organ failure, seizures, and fetal and maternal death.

For this analysis, the researchers used the National Patient Register and Medical Birth Register to identify women in Denmark who had at least one pregnancy ending in live birth or stillbirth between 1978 and 2012.

They included women who had gestational hypertension, moderate preeclampsia or severe preeclampsia any time between one month before delivery and seven days postpartum. They excluded women with cardiovascular disease or diabetes more than one month before their first registered delivery as well as those whose pregnancies had a gestational length of less than 20 weeks.

Out of more than 2 million pregnancies, 12,974 were complicated by severe preeclampsia, 44,711 were complicated by moderate preeclampsia and 18,423 were complicated by gestational hypertension.

After a mean follow-up period of 17.9 years, 10.7 percent of women who developed cardiomyopathy had a history of hypertensive disorders of pregnancy. Women with hypertensive disorders of pregnancy had significantly increased rates of cardiomyopathy, which persisted more than five years after their 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,” the researchers wrote. “The results suggest that links with [a history of hypertensive disorders of pregnancy] might be associated with a substantial proportion of idiopathic cardiomyopathy cases in women.”

They added that the American Heart Association recommends monitoring for ischemic heart disease after preeclampsia, but they said a similar recommendation would not be suitable for cardiomyopathy. However, they suggested physicians consider the association between ischemic heart disease and a history of hypertensive disorders of pregnancy during checkups.

The results did not change after adjusting for diabetes and smoking. Sensitivity analyses suggested that the relationship between a history of hypertensive disorders of pregnancy and cardiomyopathy was independent of ischemic heart disease, according to the researchers.