Heart Disorders During Pregnancy
Most women who have heart disorders—including heart valve disorders (such as mitral valve prolapse) and some birth defects of the heart—can safely give birth to healthy children, without any permanent ill effects on heart function or life span. However, women who have moderate or severe heart failure before pregnancy are at considerable risk of problems. Before becoming pregnant, such women should talk to their doctor to make sure their disorder is being treated as effectively as possible.
For women with some types of heart disorders, pregnancy is inadvisable because it greatly increases the risk of death. These disorders include
Pulmonary hypertension (high blood pressure in the arteries of the lungs)
Certain heart birth defects, including Eisenmenger syndrome (a complication of some heart defects) and sometimes coarctation of the aorta
Sometimes Marfan syndrome (a hereditary connective tissue disorder)
Severe aortic stenosis (narrowing of opening of the aortic heart valve)
Heart damage (cardiomyopathy) that occurred in a previous pregnancy
If women who have one of these disorders become pregnant, doctors advise them to terminate the pregnancy as early as possible.
Pregnancy requires the heart to work harder. Consequently, pregnancy may worsen a heart disorder or cause a heart disorder to produce symptoms for the first time. Usually, the risk of death (to the woman or fetus) is increased only when a heart disorder was severe before the woman became pregnant. However, depending on the type and severity of the heart disorder, serious complications may develop in more than 10% of women. These complications include accumulation of fluid in the lungs (pulmonary edema), an abnormal heart rhythm, and stroke.
The risk of problems increases throughout pregnancy as demands on the heart increase. Pregnant women with a heart disorder may become unusually tired and may need to limit their activities. Rarely, women with a severe heart disorder are advised to have an abortion early in pregnancy. Risk is also increased during labor and delivery. After delivery, women with a severe heart disorder may not be out of danger for 6 months, depending on the type of heart disorder.
A heart disorder in pregnant women may affect the fetus. The fetus may be born prematurely. Women with certain birth defects of the heart are more likely to have children with similar birth defects. Ultrasonography can detect some of these defects before the fetus is born. If a severe heart disorder in a pregnant woman suddenly worsens, the fetus may die.
The heart’s walls (myocardium) may be damaged (called cardiomyopathy) late in pregnancy or after delivery. This time frame is called the peripartum period, and thus, this disorder is called peripartum cardiomyopathy. The cause is unknown. This disorder tends to occur in women with one of the following characteristics:
They have had several pregnancies.
They are 30 or older.
They are carrying more than one fetus.
They have preeclampsia (a type of high blood pressure that occurs during pregnancy).
In some women, heart function does not return to normal after pregnancy. Peripartum cardiomyopathy tends to occur in subsequent pregnancies, particularly if heart function has not returned to normal. Thus, women who have had this disorder are often discouraged from becoming pregnant again.
Peripartum cardiomyopathy can result in heart failure, which is treated as usual except that angiotensin-converting enzyme (ACE) inhibitors and aldosterone antagonists (spironolactone and eplerenone) are not used.
Ideally, heart valve disorders are diagnosed and treated before the women become pregnant. Doctors often recommend surgical treatment for women with severe disorders.
The valves most often affected in pregnant women are the aortic and mitral valves. Disorders that cause the opening of a heart valve to narrow (stenosis) are particularly risky. Stenosis of the mitral valve can result in fluid accumulating in the lungs (pulmonary edema) and a rapid, irregular heart rhythm (atrial fibrillation).
Women with mitral valve prolapse usually tolerate pregnancy well.
Doctors advise pregnant women with a heart disorder to do the following:
Anemia, if it develops, is promptly treated.
Certain drugs used to treat heart disorders are not used during pregnancy. They include angiotensin-converting enzyme (ACE) inhibitors, aldosterone antagonists (spironolactone and eplerenone), and certain drugs used to treat abnormal heart rhythms (antiarrhythmic drugs, such as amiodarone). Which other heart drugs are continued during pregnancy depends on how severe the heart disorder is and what the risks to the fetus are. For example, warfarin is usually avoided because it can increase the risk of birth defects. However, it may be given to women who have a mechanical heart valve because warfarin reduces the risk that blood clots will form in these valves. Such clots can be fatal.
If the heart is not functioning well, women may be given digoxin (used to treat heart failure) and advised to limit their activities as much as possible, beginning at 20 weeks of pregnancy.
During labor, pain is treated as needed. If women have a severe heart disorder, doctors may inject an anesthetic into the lower back—into the space between the spine and the outer layer of tissue covering the spinal cord (epidural space). This procedure is called an epidural injection. This anesthetic blocks sensation in the lower spinal cord, reducing the stress response to pain and the urge to push. The purpose is to reduce the strain on the heart. Pushing during labor strains the heart because it makes the heart work harder. Because these women cannot push, the baby may have to be delivered with forceps or a vacuum extractor.
An epidural injection should not be used if women have aortic valve stenosis. A local anesthetic or, if needed, a general anesthetic is used instead.
Women are monitored closely immediately after delivery and are checked periodically by a cardiologist for several weeks afterward.