Peripartum cardiomyopathy is a cardiomyopathy with systolic dysfunction that usually presents at the end of pregnancy and in the first weeks of the postpartum period. Risk factors include Afro-descendant ethnicity, gestational hypertension, preeclampsia, maternal age greater than 30 years, and multiple gestation.
Several pathophysiological mechanisms involved have been elucidated, such as an increase in prolactin, a decrease in antioxidant transcriptional factors such as STAT3, and an increase in proteins produced in the placenta such as sFLT-1, which together produce endothelial dysfunction and apoptosis of the placenta.
What is peripartum cardiomyopathy?
Peripartum cardiomyopathy (PPCM), also known as “postpartum cardiomyopathy,” is a rare form of heart failure that manifests during the last month of pregnancy or up to five months after delivery. The term “cardiomyopathy” literally means “heart muscle disease.”
Peripartum cardiomyopathy is a dilated form of the condition when the heart chambers enlarge and the muscle weakens. This causes a decrease in the percentage of blood ejected from the left ventricle of the heart with each contraction. That leads to less blood flow. Then the heart can’t meet the demands of the body’s organs for oxygen, affecting the lungs, liver and other body systems.
Peripartum cardiomyopathy is rare in the United States, Canada, and Europe. About 1,000 to 1,300 women develop the condition in the US each year. PPCM is much more common in some countries and may be related to differences in diet, lifestyle, other medical conditions or genetics.
How is it diagnosed?
Peripartum cardiomyopathy may be difficult to detect because symptoms of heart failure can mimic those of third trimester pregnancy, such as swelling in the feet and legs, and some shortness of breath. More extreme cases include severe shortness of breath and prolonged swelling after delivery.
During a physical exam, health care professionals will look for signs of fluid in the lungs. They will use a stethoscope to listen for lung crackles, a rapid heart rate or abnormal heart sounds. An echocardiogram can detect cardiomyopathy by showing the diminished functioning of the heart.
PPCM is diagnosed when the following three criteria are met:
- Heart failure develops in the last month of pregnancy or within five months of delivery.
- Heart pumping is reduced, with an ejection fraction (EF) less than 45% (typically measured by an echocardiogram). EF is how much blood the left ventricle pumps out with each contraction. A normal EF can be between 55 and 70.
- No other cause of heart failure with reduced EF is noted.
Laboratory blood tests are a standard part of the evaluation. This includes tests to assess kidney, liver and thyroid function; tests to assess electrolytes, including sodium and potassium; and a complete blood count to look for anemia or evidence of infection. Markers of cardiac injury and stress can also assess level of risk.
Some symptoms of this condition are:
- Feeling like your heart is beating fast or irregularly (palpitations)
- Increased nighttime urination
- Shortness of breath with activity and when lying down
- Swollen ankles
- Swollen neck veins
- Low blood pressure or pressure drops when standing up.
The New York Heart Association system classifies the severity of symptoms in patients with peripartum cardiomyopathy:
- Class I: disease without symptoms
- Class II: Mild symptoms/effect on function or symptoms only with extreme exertion
- Class III: symptoms with minimal exertion
- Class IV: symptoms at rest.
What are the causes?
The underlying cause is unclear. Heart biopsies in some cases show women have inflammation in the heart muscle. This may be because of prior viral illness or abnormal immune response. Other potential causes include poor nutrition, coronary artery spasm, small-vessel disease and defective antioxidant defenses. Genetics may also play a role.
Initially thought to be more common in women older than 30, peripartum cardiomyopathy has since been reported across a wide range of age groups. Several risk factors include:
- Advanced maternal age
- History of cardiac disorders, such as heart attack, heart valve dysfunction or myocarditis (inflammation of the heart muscle)
- Exposure to toxins, such as alcohol or chemotherapy
- Arterial hypertension
- Multiple pregnancies
- Multifetal pregnancy (ie, twins)
- Use of certain medications to prevent premature labor
- African descent
- Poor nutrition.
How can PPCM be treated?
The goal of treating peripartum cardiomyopathy is to prevent extra fluid from building up in the lungs and to help the heart heal as best it can. Many women regain normal heart function or are stabilized with medication. Some develop severe heart failure requiring mechanical assistance or heart transplantation.
A physician can prescribe several classes of medications to treat symptoms, with variations that are safer for women who are breastfeeding.
- Angiotensin converting enzyme (ACE) inhibitors – Help the heart work more efficiently
- β blockers – make the heart beat more slowly so you have time to recover.
- Diuretics : reduce fluid retention.
- Digitalis : a group of substances derived from the foxglove plant that have been used for more than 200 years to treat heart failure. Digitalis strengthens the heart’s pumping ability.
- Anticoagulants : they favor the dilution of the blood. Patients with PPCM are at increased risk of developing clots, especially if the EF is very low.
Health care professionals may recommend a low-sodium diet, fluid restrictions or daily weighing. A weight gain of 3 to 4 pounds or more over a day or two may signal a fluid buildup.
Women who smoke and drink alcohol will be advised to stop, because these habits may make the symptoms worse.
A heart biopsy may help determine if the underlying cause of cardiomyopathy is a heart muscle infection (myocarditis). But this procedure is uncommon.
How can women minimize the risk?
To develop and maintain a strong heart, women should avoid cigarettes and alcohol, eat a balanced diet, and exercise regularly. Women who develop peripartum cardiomyopathy are at high risk of developing the same condition in subsequent pregnancies.
Possible future developments
Ongoing studies continue to help researchers better understand the cause of peripartum cardiomyopathy and develop new treatments. Health care professionals have tried treatments that alter the immune system, such as intravenous γ-globulin and immunoabsorption, but they’re not proven. Researchers have also focused on the role of prolactin in peripartum cardiomyopathy.
Prolactin is a hormone released from the pituitary gland late in pregnancy and after delivery that stimulates breast milk production. But prolactin may have adverse effects on the heart muscle by limiting its blood supply and causing cell death. Bromocryptine is a medication that inhibits the pituitary secretion of prolactin. Early studies suggest it helps treat peripartum cardiomyopathy, but more research is needed.