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Cardiovascular Disease in Pregnancy

A woman who has a history of heart disease, heart murmur, rheumatic fever or high blood pressure should talk with her healthcare provider before she decides to become pregnant. A woman who has congenital heart disease has a higher risk of having a baby with some type of heart defect. If this is your case, it's very important to visit your healthcare provider often. You may need to have diagnostic tests done, such as a fetal ultrasound test.

Cardiovascular disease ranks fourth (after infection, toxemia, and hemorrhage) among the leading causes of maternal death. The physiologic stress of pregnancy and delivery is often more than a compromised heart can tolerate and often leads to maternal and fetal death.

Approximately 1% to 2% of pregnant women have cardiac disease, but the incidence is rising because medical treatment today allows more females with rheumatic heart disease and congenital defects to reach childbearing age.

With careful management, the prognosis for the pregnant patient with cardiovascular disease is good. Decompensation is the leading cause of maternal death. Infant mortality increases with decompensation because uterine congestion, insufficient oxygenation, and the elevated carbon dioxide content of the blood not only compromise the fetus but also frequently cause premature labor and delivery.

Causes

Rheumatic heart disease is present in more than 80% of patients who develop cardiovascular complications. In the rest, these complications stem from congenital defects (10% to 15%) and coronary artery disease (2%).

The diseased heart is sometimes unable to meet the normal demands of pregnancy: a 25% increase in cardiac output, a 40% to 50% increase in plasma volume, increased oxygen requirements, retention of salt and water, weight gain, and alterations in hemodynamics during delivery. This physiologic stress often leads to the heart's failure to maintain adequate circulation (decompensation).

The degree of decompensation depends on the patient's age, the duration of cardiac disease, and the functional capacity of the heart at the outset of pregnancy.

Signs and symptoms

Typical clinical features of cardiovascular disease in pregnancy include distended neck veins, diastolic murmurs, moist basilar pulmonary crackles, cardiac enlargement (discernible on percussion or as a cardiac shadow on a chest X-ray), and cardiac arrhythmias (other than sinus or paroxysmal atrial tachycardia). Other characteristic abnormalities may include cyanosis, pericardial friction rub, pulse delay, and pulsus alternans.

Diagnosis

Determination of the extent and cause of the disease may necessitate electrocardiography, echocardiography (for valvular disorders such as rheumatic heart disease), or phonocardiography. X-rays show cardiac enlargement and pulmonary congestion. Cardiac catheterization should be postponed until after delivery, unless surgery is necessary.

Treatment

Specific treatments vary before, during, and after delivery

Before delivery

The goal of antepartum management is to prevent complications and minimize the strain on the mother's heart, primarily through rest. This may require periodic hospitalization for patients with moderate cardiac dysfunction or with symptoms of decompensation, toxemia, or infection. Older women or those with previous decompensation may require hospitalization and bed rest throughout the pregnancy.

Drug therapy is often necessary and should always include the safest possible drug in the lowest possible dose to minimize harmful effects to the fetus. Diuretics and drugs that increase blood pressure, blood volume, or cardiac output should be used with extreme caution.

If an anticoagulant is needed, heparin is the drug of choice. Digitalis glycosides and common antiarrhythmics, such as quinidine and procainamide, are often required. The prophylactic use of antibiotics is reserved for patients who are susceptible to endocarditis.

A therapeutic abortion may be considered for patients with severe cardiac dysfunction, especially if decompensation occurs during the first trimester. Patients hospitalized with heart failure usually follow a regimen of digitalis glycosides, oxygen, rest, sedation, diuretics, and restricted intake of sodium and fluids. Patients whose symptoms of heart failure don't improve after treatment with bed rest and digitalis glycosides may require cardiac surgery, such as valvotomy and commissurotomy.

During delivery

The patient in labor may require oxygen and an analgesic, such as meperidine or morphine, for relief of pain and apprehension without undue depression of the fetus or herself. Depending on which procedure promises to be less stressful for the patient's heart, delivery may be vaginal or by cesarean section.

After delivery

Bed rest and medications already instituted should continue for at least I week after delivery because of a high incidence of decompensation, cardiovascular collapse, and maternal death during the early puerperal period. These complications may result from the sudden release of intra-abdominal pressure at delivery and the mobilization of extracellular fluid for excretion, which increase the strain on the heart, especially if excessive interstitial fluid has accumulated.

Breast-feeding is undesirable for patients with severely compromised cardiac dysfunction, because it increases fluid and metabolic demands on the heart.

Some important things for any pregnant woman to do:

• Eat a nutritious diet.
• Don't smoke or drink alcohol.
• Have your doctor approve any medicine you use (including over-the-counter drugs).

Some medicines that are safe to take when you're not pregnant should not be used when you're pregnant. They may harm your baby. If you have heart disease, you may need to take heart medications during your pregnancy. Your doctor can prescribe heart drugs that won't harm your baby.