Cardiovascular conditions, including cardiomyopathy, are responsible for approximately 26% of all pregnancy-related deaths. In the United States, because incidence of rheumatic heart disease has markedly declined, most heart problems during pregnancy result from congenital heart disease. However, in Southeast Asia, Africa, India, the Middle East, and parts of Australia and New Zealand, rheumatic heart disease is still common.
Despite dramatic improvements in survival and quality of life for patients with severe congenital heart defects and other heart disorders, pregnancy remains inadvisable for women with certain high-risk conditions such as the following (1):
Pulmonary hypertension (pulmonary artery systolic pressure > 25 mm Hg) caused by any condition, including Eisenmenger syndrome
Coarctation of the aorta if uncorrected or if accompanied by an aneurysm
Marfan syndrome with aortic root diameter of > 4.5 cm
Severe symptomatic aortic stenosis or severe mitral stenosis
Bicuspid aortic valve with ascending aorta diameter > 50 mm
A single ventricle and impaired systolic function (whether treated with the Fontan procedure or not)
Cardiomyopathy with ejection fraction < 30% or New York Heart Association (NYHA) class III or IV heart failure (see table New York Heart Association (NYHA) Classification of Heart Failure)
General reference
1. European Society of Gynecology (ESG); Association for European Paediatric Cardiology (AEPC); German Society for Gender Medicine (DGesGM): ESC Guidelines on the management of cardiovascular diseases during pregnancy: the Task Force on the Management of Cardiovascular Diseases During Pregnancy of the European Society of Cardiology (ESC). Eur Heart J 32 (24):3147–3197, 2011. doi: 10.1093/eurheartj/ehr218
Pathophysiology of Heart Disease in Pregnancy
Pregnancy stresses the cardiovascular system, often worsening known heart disease; mild heart disease may first become evident during pregnancy.
Stressors include decreased hemoglobin and increased blood volume, stroke volume, and eventually heart rate. Cardiac output increases by 30 to 50%. These changes become maximal between 28 and 34 weeks gestation.
During labor, cardiac output increases about 20% with each uterine contraction; other stressors include straining during the 2nd stage of labor and the increase in venous blood returning to the heart from the contracting uterus. Cardiovascular stressors do not return to prepregnancy levels until several weeks after delivery.
Symptoms and Signs of Heart Disease in Pregnancy
Findings resembling heart failure (eg, mild dyspnea, systolic murmurs, jugular venous distention, tachycardia, dependent edema, mild cardiomegaly seen on chest x-ray) typically occur during normal pregnancy or may result from heart disease. Diastolic or presystolic murmurs are more specific for heart disease.
Heart failure can cause premature labor or arrhythmias. Risk of maternal or fetal death correlates with New York Heart Association (NHYA) functional classification, which is based on the amount of physical activity that causes symptoms of heart failure.
Risk is increased only if symptoms
Occur during mild exertion (NYHA class III)
Occur during minimal or no exertion (NYHA class IV)
Diagnosis of Heart Disease in Pregnancy
History and physical examination
Usually echocardiography
Diagnosis of heart disease during pregnancy is usually based on clinical evaluation and echocardiography.
Because genetics can contribute to the risk of heart disease, genetic counseling and fetal echocardiography should be offered to women with congenital heart disease.
Treatment of Heart Disease in Pregnancy
For New York Heart Association (NYHA) class III or IV, activity restriction and possibly bed rest after 20 weeks
Most other usual treatments for heart failure and arrhythmias
Frequent prenatal visits, ample rest, avoidance of excessive weight gain and stress, and treatment of anemia are required. An anesthesiologist familiar with heart disease in pregnancy should attend the labor and ideally should be consulted prenatally. During labor, pain and anxiety are treated aggressively to minimize tachycardia. Women are closely monitored immediately postpartum and are followed for several weeks postpartum by a cardiologist.
Before women with NYHA class III or IV status conceive, the heart disease should be optimally treated medically and, if indicated (eg, if due to a valvular heart disease), treated surgically. Women with class III or IV heart failure or another high-risk disorder (listed above) may be advised to obtain an early therapeutic abortion.
Arrhythmias
Atrial fibrillation may accompany cardiomyopathy or valvular disordersMedications for Arrhythmias
AnticoagulationSome Drugs With Adverse Effect During Pregnancy
Management of acute supraventricular tachycardia or ventricular tachycardia is the same as for nonpregnant patients.
Endocarditis prophylaxis
For pregnant patients with a structural heart disorder, indications and use of endocarditis prophylaxis for nonobstetric events are the same as those for nonpregnant patients. The American Heart Association guidelines do not recommend endocarditis prophylaxis for vaginal and cesarean deliveries because the rate of bacteremia is low. However, in the highest-risk patients (eg, those with prosthetic heart materials, a history of endocarditis, an unrepaired congenital cyanotic heart lesion, or a heart transplant with a valvulopathy), prophylaxis is often considered when the membranes rupture, even though no evidence indicates any benefit.
If patients with a structural heart disorder develop chorioamnionitis or another infection (eg, pyelonephritis) requiring hospital admission, the antibiotics used to treat the infection should cover the pathogens most likely to cause endocarditis.
Key Points
Pregnancy may not be advisable for women with certain high-risk heart disease (eg, pulmonary hypertension, coarctation of the aorta if uncorrected or accompanied by an aneurysm, Marfan syndrome with aortic root diameter of > 4.5 cm, severe symptomatic aortic stenosis, severe mitral stenosis, bicuspid aortic valve with ascending aorta > 50 mm, a single ventricle with impaired systolic function, cardiomyopathy, NYHA class III or IV heart failure).
Indications for endocarditis prophylaxis for pregnant patients with a structural heart disorder are the same as those for other patients.
Valvular Stenosis and Insufficiency in Pregnancy
During pregnancy, valvular stenosis and regurgitation (insufficiency) most often affect the mitral and aortic valves. Mitral stenosis is the most common valvular disorder during pregnancy.
Pregnancy amplifies the murmurs of mitral stenosis and aortic stenosis but diminishes those of mitral and aortic regurgitation. During pregnancy, mild mitral or aortic regurgitation is usually easy to tolerate; stenosis is more difficult to tolerate and predisposes to maternal and fetal complications. Mitral stenosis is especially dangerous; the tachycardia, increased blood volume, and increased cardiac output during pregnancy interact with this disorder to rapidly increase pulmonary capillary pressure, causing pulmonary edema. Atrial fibrillation is also common.
Treatment
For mitral stenosis, prevention of tachycardia, treatment of pulmonary edema and atrial fibrillation, and sometimes valvotomy
For aortic stenosis, surgical correction before pregnancy if possible
Ideally, valvular disorders are diagnosed and treated medically before conception; surgical correction is often recommended for severe disorders. Prophylactic antibiotics are required in certain situations (eg, for endocarditis prophylaxis).
Mitral stenosis
Patients must be closely observed throughout pregnancy because mitral stenosis may rapidly become more severe. If required, valvotomy is relatively safe during pregnancy; however, open heart surgery increases fetal risk. Tachycardia should be prevented so that diastolic flow through the stenotic mitral valve can be maximized.
If pulmonary edema occurs, loop diuretics can be used.
During labor, conduction anesthesia (eg, slow epidural infusion) is usually preferred.
Aortic stenosis
Aortic stenosis should be corrected before pregnancy if possible because surgical repair during pregnancy has more risks and catheter valvuloplasty is not very effective.
During labor, local anesthesia is preferred, but if necessary, general anesthesia is used. Conduction anesthesia should be avoided because it decreases filling pressures (preload), which may already be decreased by aortic stenosis.
Straining, which can suddenly reduce filling pressures and impair cardiac output, is discouraged during the 2nd stage of labor; operative vaginal delivery is preferred. Cesarean delivery is done if indicated for obstetric reasons.
