What is peripartum cardiomyopathy?
Peripartum cardiomyopathy (PPCM), also known as postpartum cardiomyopathy, is an uncommon form of heart failure that happens towards the end of pregnancy or in the months following delivery, when no other cause of heart failure can be found. PPCM is most commonly diagnosed in the last month of pregnancy and the weeks following delivery but can occur 5 months or more postpartum. PPCM is diagnosed in individuals without a prior diagnosis of heart disease. Cardiomyopathy literally means heart muscle disease but is often described as heart muscle weakness.
In PPCM the heart chambers enlarge and the heart muscle weakens. This causes a decrease in the amount of blood the heart pumps with each heartbeat. The percentage of blood ejected from the heart with each contraction is called the left ventricular ejection fraction (LVEF). A weakened heart can cause fatigue and low blood pressure due to less blood flow to your body, and can cause swelling in legs and abdomen due to fluid buildup in organs like the lungs and liver.
PPCM is rare in the United States, Canada, and Europe. In the US, PPCM is diagnosed in 1 in every 1,000 to 1 in every 4,000 deliveries. The number of patients diagnosed with PPCM appears to be increasing over time. PPCM may be more common in other countries such as Haiti, Nigeria, and South Africa.
How is it diagnosed?
PPCM may be difficult to detect because symptoms of heart failure can mimic those of pregnancy, such as shortness of breath and swelling in the feet and legs. Any new shortness of breath or swelling that occurs after delivery or sudden onset of these symptoms during pregnancy should lead to prompt evaluation.
During a physical exam, health care professionals will look for signs of fluid in the lungs. They may use x-ray to see, or a stethoscope to listen for, evidence of fluid in the lungs, a rapid heart rate or abnormal heart sounds. A heart ultrasound, called an echocardiogram, can detect cardiomyopathy by showing that the heart function is weak. Lab tests may also be done to confirm the diagnosis.
PPCM is diagnosed when the following three criteria are met:
- Heart failure develops in the last month of pregnancy or within months following delivery.
- Heart pumping is reduced, with a left ventricular ejection fraction less than 45% (typically measured by an echocardiogram). A normal LVEF is between 50% and 70%.
- No other cause for heart failure can be found.
Laboratory blood tests are a standard part of the evaluation. This includes tests to assess kidney, electrolytes, liver, thyroid function and a complete blood count to look for anemia or evidence of infection. Brain Natriuretic Peptide (BNP) and N-Terminal Pro-BNP levels will be significantly elevated in PPCM, and are used as heart failure indications. Markers of cardiac injury and stress can also assess level of risk.
Symptoms of the condition include:
- Shortness of breath with activity and when lying flat
- Swollen ankles or feet
- Chest pain or tightness
- Less common symptoms may include feeling of heart racing or skipping beats (palpitations), fatigue, increased nighttime urination or light-headedness, especially when standing up
It's important to talk to a health care professional if you are concerned that you have symptoms of PPCM.
The New York Heart Association system classifies the severity of symptoms in patients with PPCM:
- Class I - Disease with no 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, and likely involves several factors. Research suggests that PPCM may be triggered by prior viral illness, nutritional deficiency, hemodynamic stress during pregnancy or an abnormal immune response. These causes have not been proven.
More recent research suggests that PPCM may be caused by the overactivity of certain hormones that cause damage to the vascular system. These hormone levels have been found to be higher in women with preeclampsia, which could help explain why they are at higher risk of developing PPCM. It is not clear why some women may be more predisposed to the effects of these hormones than others. Genetics or family history may also play a role, although most women who develop PPCM have no family history of cardiomyopathy.
Several risk factors include:
- Maternal age of 35+
- High blood pressure, including preeclampsia or gestational hypertension
- Multiple gestations (e.g., twins)
- PPCM is more common in patients who identify as Black or African-American, though it is not understood how race plays a role in the development of PPCM
How can PPCM be treated?
The goal of peripartum cardiomyopathy treatment is to improve heart function and keep extra fluid from collecting in the lungs or other parts of your body. With medical therapy, many women with PPCM recover normal heart function within the first 3 to 6 months of treatment. A small number of patients with PPCM will develop severe heart failure requiring mechanical heart pumps or heart transplant.
A physician can prescribe several classes of medications to treat symptoms and help the heart function recover. Medications below are common to treat heart failure but health care professionals may not use some medications if you are breastfeeding or pregnant.
- Angiotensin Converting Enzyme (ACE) inhibitors/Angiotensin Receptor Blockers (ARBs) – Lower blood pressure and helps the heart work more efficiently.
- Angiotensin Receptor/Neprilysin Inhibitor (ARNI) – Lower blood pressure and makes it easier for the heart to pump blood.
- Beta blockers – Cause the heart to beat more slowly so it has recovery time.
- Diuretics – Reduce fluid retention.
- Digitalis – Strengthens the pumping ability of the heart but due to narrow safety margins with need to monitor levels it is frequently not used.
- Anticoagulants – Help thin the blood. Patients with PPCM are at increased risk of developing blood clots, especially if the EF is very low.
- Inotropic therapies – Used in intensive care and for advanced heart failure to help the heart beat stronger.
- Bromocriptine – Blocks the release of prolactin, a hormone that promotes lactation. Bromocriptine may help the heart recover, but additional research is needed to understand if bromocriptine should be prescribed for all patients with severe PPCM.
Health care professionals may institute a low-salt diet, fluid restrictions and measurements of daily weight. A weight gain of 3 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 make the condition worse.
How can women minimize their risk?
To develop and maintain a strong heart, women should avoid cigarettes and alcohol and eat a well-balanced diet. Women who develop peripartum cardiomyopathy are at high risk of developing the same condition with future pregnancies, if LVEF has not recovered. Your health care professional may discuss contraception with you in order to avoid unintended pregnancy.
Ongoing studies continue to help researchers better understand the cause of PPCM and develop new treatments. Health care professionals have tried treatments that alter the immune system. Researchers also have focused on the role of prolactin in PPCM. 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. Bromocriptine is a medication that inhibits the pituitary secretion of prolactin. Early studies suggest it helps treat PPCM, but more research is needed.