Congenital heart conditions and pregnancy
Congenital heart defects are the most common heart problems that affect women of childbearing age. These include shunt lesions, obstructive lesions, complex lesions and cyanotic heart disease.
Shunt lesions are the simplest and most common congenital heart defects. Shunts include atrial septal defect (ASD), which is a hole between the upper chambers of the heart; ventricular septal defect (VSD), which is a hole between the lower chambers of the heart; and patent ductus arteriosus (PDA), which means there is abnormal blood flow between the aorta and pulmonary artery. If the hole is large, a fair amount of blood from the left side of the heart will flow back into the right side of the heart. The blood gets pumped back to the lungs again and causes strain on the heart. This can lead to an enlarged heart, abnormal heart rhythms and increased pressure in the lungs (pulmonary hypertension). Pulmonary hypertension, when severe, can cause the blood flow across the shunt to move in reverse. This can cause low levels of oxygen in the blood (cyanosis). In such cases, pregnancy is not recommended due to the high risk of the mother dying.
Obstructive lesions reduce the amount of blood flow to the heart and the body’s major blood vessels. One such lesion, aortic coarctation is a narrowing in the descending aorta, which is the largest artery in the body. Aortic coarctation can cause a pregnant woman to have high blood pressure. The condition can also keep the placenta (the collection of blood vessels that supplies the baby with blood) from getting enough blood. Depending on how severe the narrowing is, you may need a procedure before or during pregnancy to keep you and the baby safe during pregnancy.
Complex lesions include transposition of the great arteries. This means the aorta and pulmonary arteries are attached to the wrong ventricles (bottom chambers of the heart). Surgery to repair the problem can cause problems with the heart chambers, especially if the right ventricle pumps blood out to the body (this is usually the job of the left ventricle). In this case, the problem can cause heart failure and leaky heart valves, and the conditions can become worse during pregnancy. If you have this condition, you will need to be closely followed during pregnancy.
Cyanotic heart disease includes tetralogy of Fallot. This is a condition that includes a VSD, narrowing of the pulmonary valve and abnormal configuration of the aorta. Treatment usually keeps cyanosis from recurring. However, the repair can cause a leaky pulmonary valve, and that problem can lead to heart failure and heart rhythm disturbances. If you have a leaky pulmonary valve, you may need to have it corrected before you become pregnant.
In general, most women with congenital heart defects, especially those who have had corrective surgeries, can safely become pregnant. However, the outcome of the pregnancy and risk of complications depends on the type of heart defect you have, how severe your symptoms are, and whether you have heart muscle dysfunction, heart rhythm disturbances or pulmonary hypertension with related lung disease. Your pregnancy can also be affected if you have had particular types of heart surgery.
Special considerations before and during pregnancy
Congenital heart defects (in either the mother or father) increase the baby’s risk of having a heart problem. Your cardiologist may refer you to a geneticist for further evaluation. A fetal echocardiogram may be recommended to check the baby’s heart for possible defects. This test is usually done in the 18th week of pregnancy.
If you have been diagnosed with a congenital heart defect, a cardiologist should evaluate your heart condition before you plan a pregnancy. The cardiologist will talk to you about the possible risks of pregnancy and can work with your healthcare team to monitor your health and your baby’s health while you are pregnant.
Valve disease and pregnancy
Aortic valve stenosis means the aortic valve (the valve between the left ventricle and the aorta) is narrowed or stiff. If the narrowing is severe, the heart has to work harder to pump the increased blood volume out of the narrowed valve. This, in turn, can cause the left ventricle (the major pumping chamber of the heart to enlarge – a condition called hypertrophy). Over time, symptoms of heart failure can occur or become worse and increase the risk of long-term complications for the mother.
One common cause of aortic valve stenosis is bicuspid aortic valve disease. This is a congenital heart condition in which there are only two leaflets (also called cusps), instead of the normal three leaflets inside the valve. The leaflets open and close to keep blood flowing in the right direction and prevent backflow. Without the third leaflet, the valve can become narrowed or stiff.
Women with bicuspid aortic valve disease or any type of aortic valve stenosis need to be evaluated by a cardiologist before planning a pregnancy. In some cases, surgery is recommended to correct the valve before pregnancy.
Mitral valve stenosis means the mitral valve (the valve between the left atrium and left ventricle) is narrowed. This condition is often caused by rheumatic fever.
The increased blood volume and increased heart rate that occur during pregnancy can make symptoms of mitral stenosis get worse. The left atrium can become bigger and cause a rapid, irregular heart rhythm called atrial fibrillation. In addition, the problem can cause heart failure symptoms (shortness of breath, irregular heart beat, fatigue and swelling/edema). This can increase the risk to the mother. If you have mitral valve stenosis, you may need to take medications while you are pregnant. Your doctor may also recommend an catheter-based procedure, called percutaneous valvuloplasty, to correct the narrowed valve while you are pregnant. It is important to have mitral stenosis evaluated before you become pregnant. In some cases, surgery or valvuloplasty to correct the valve will be recommended before pregnancy.
Mitral valve prolapse is a common condition that usually doesn’t cause symptoms or require treatment. Most patients with mitral valve prolapse tolerate pregnancy well. If the prolapse causes a severe leak, you may need treatment before you become pregnant. Be sure to talk to your doctor if you plan to become pregnant and follow any recommendations.
Pregnancy in women with prosthetic (artificial) valves
Women who have artificial heart valves may experience complications during pregnancy because:
- Women who have an artificial heart valve need to take lifelong anticoagulant medication, and certain anticoagulant medications can be harmful to the baby. There is controversy about which anticoagulant medication regimen is best during pregnancy.*
- During pregnancy, there is an increased risk of blood clots.
*Use of warfarin, heparin, aspirin, and combinations of these anticoagulant medications have been suggested and compared. The most recent recommendations from the European Heart Association are to use heparin during the first trimester, followed by warfarin up to the 36th week of pregnancy, and subsequent replacement with heparin until delivery OR to use oral anticoagulation medication throughout pregnancy, until the 36th week, followed by heparin until delivery.
The use of warfarin is less harmful if the dose is kept to less than 5 mg. In addition, other specialists have recommended the addition of low-dose aspirin to treat women who are at high risk.
If you have a prosthetic valve and are taking an anticoagulant medication, it is very important to be evaluated by a cardiologist before planning a pregnancy. The cardiologist will talk to you about your potential risks and determine the best anticoagulant therapy routine for you.
In addition, ask your doctor what precautions you should continue to follow to prevent endocarditis.
Arrhythmias and pregnancy
Abnormal heartbeats (arrhythmias) during pregnancy are common. Women who have never had an arrhythmia or heart problem may first develop an arrhythmia during pregnancy. When an arrhythmia develops during pregnancy, it can be a sign of a heart condition you didn’t know you had. Most of the time, the arrhythmia causes little in the way of symptoms and does not require treatment. If you have symptoms, your doctor may order tests to determine the type arrhythmia you have and attempt to determine its cause.
Aorta Disease and pregnancy
Women who have conditions that affect the aorta, such as aortic aneurysm, dilated aorta, or connective tissue disorders such as Marfan syndrome, are at increased risk during pregnancy.
Pressure in the aorta increases during pregnancy and when bearing down during labor and delivery. This extra pressure increases the risk of an aortic dissection or rupture, which can be life-threatening.
It is very important for women who have aorta disease to be evaluated by a cardiologist before planning a pregnancy. A thorough evaluation of your condition will provide the physician with information about the potential risks of pregnancy. It is also important to note that some conditions, such as Marfan syndrome, are genetic and can be passed down to children, so genetic counseling may be recommended.