We normally think of heart failure as a condition associated with older people, but the risk of heart failure is particularly high among women who are pregnant, or have recently given birth. Pregnancy stresses the cardiovascular system and can worsen underlying heart problems, such as high blood pressure, and cause new heart issues such as cardiomyopathy, the enlargement of the heart. Women are most at risk for heart failure within the six weeks after delivery, the postpartum period, a study has found.

Heart failure occurs when the heart is not able to pump blood effectively enough to meet the body's needs. Symptoms include shortness of breath, excessive tiredness and swelling in the legs. The risk of having a heart attack builds from a woman's third trimester as the demands of labor and delivery place even more burden on the stressed heart. It remains even after a woman has given birth.

The rate of pregnancy-related deaths more than doubled between 1987 and 2011.

The study looked at the incidence and prevalence of heart failure during pregnancy, delivery and the first few weeks following the birth of a child, using data from over 50 million pregnancy-related hospitalizations of women, aged 13 to 49, between 2001 and 2011. The rate of pregnancy-related deaths more than doubled between 1987 and 2011, and there was an almost five percent increase in women being admitted to the hospital with heart failure before delivery every year during the study period. About 60 percent of these heart failure diagnoses occurred after delivery; 27 percent occurred during delivery; and 13 percent happened before delivery.

There are some clear risk factors for pregnancy-related heart failure, the University of Illinois at Chicago researchers found. New mothers or mothers-to-be who were diagnosed with heart failure were more likely to be older, African American, smokers and live in the South. They were also more likely to drink alcohol and have a low-income.

Certain health conditions also increased women's risk of heart failure: diseased heart muscle or valves, high blood pressure and diabetes. Complications of pregnancy such as preeclampsia, eclampsia and gestational diabetes also increased a woman's risk of developing heart failure.

Women are typically discharged two to three days after delivery and not followed up by a health care provider for six weeks. The findings “highlight the need for close monitoring of high-risk women before discharge after childbirth and through the postpartum period,” said the researchers, who call for better education of women about their own risk factors and about the often subtle signs and symptoms of heart failure in women.

Because pregnancy-related heart failure is often seen, historically, among disadvantaged and medically underserved populations, the authors call for greater public health measures to address prevention and treatment of this potentially devastating condition.

The study is published in Circulation: Heart Failure.