This section will provide you with information about:
Changes to the heart and blood vessels with pregnancy
During pregnancy, changes occur to the heart and blood vessels that add stress on a woman’s body and increase the workload of the heart. These changes include:
- Increase in blood volume: During the first trimester, the volume of blood increases by 40 to 50 percent and remains high throughout pregnancy.
- Increase in cardiac output: Cardiac output, the amount of blood pumped by the heart each minute, increases by 30 to 40 percent due to the increase in blood volume.
- Increase in heart rate: It is normal for the heart rate to increase by 10 to 15 beats per minute during pregnancy.
- Decrease in blood pressure: In some women, blood pressure may decrease by 10 mmHg during pregnancy. Blood pressure may decrease during pregnancy due to hormone changes and because more of your blood is directed toward the uterus. Most of the time, there are no symptoms of blood pressure changes and no treatment is required. Your health care provider will be monitoring your blood pressure during your prenatal appointments and can tell you if you need to be concerned about changes in your blood pressure.
These changes are normal during pregnancy and help ensure that your baby will get enough oxygen and nutrients. These changes can lead to symptoms including fatigue (feeling over-tired), shortness of breath, and light-headedness during pregnancy. All of these symptoms are normal, but if you are concerned, please talk to your doctor.
Women with a heart condition may need to take special precautions before and during pregnancy. Some heart conditions may increase a woman’s risk for complications during pregnancy. In addition, some women may have heart or blood vessel conditions that are not identified until pregnancy.
If you have a heart condition, what should you do before planning a pregnancy?
If you have a heart condition, such as those listed below, you should be evaluated by a cardiologist (a heart specialist) before you start planning a pregnancy:
- Hypertension (high blood pressure) or high cholesterol
- Prior diagnosis of any type of heart or blood vessel disease, including aorta disease, arrhythmia, heart murmur, cardiomyopathy, heart failure, Marfan syndrome or rheumatic fever.
- Prior cardiac event (transient ischemic attack or stroke).
- Poor functional status, defined as NYHA class III or IV. The New York Heart Association (NYHA) functional status is a set of clinical classifications that rank patients as class I-II-III-IV according to the degree of symptomatic or functional limits or cyanosis (a blue tint to the skin, indicates the body is not receiving enough oxygen-rich blood).
- Severe narrowing of the mitral or aortic valve or aortic outflow tract, as determined by echocardiography.
- Ejection fraction of less than 40%. Ejection fraction is the amount of blood pumped out of the left ventricle during each heartbeat. The ejection fraction evaluates how well the heart is pumping. A normal ejection fraction ranges from 50 to 70%.(8)
The cardiologist can review your health history and perform a physical exam and order diagnostic tests, as needed, to evaluate your heart function and the severity and extent of your condition. After reviewing the test results, the cardiologist can talk to you about the safety of pregnancy, based on your health condition. The cardiologist will discuss your potential risk of complications during pregnancy, including potential fetal risks and possible long-term health risks to you and your baby. The cardiologist can discuss whether medications or other treatments may be needed before pregnancy.
Be sure to discuss all of your medications (including heart medications and any over-the-counter medications you take routinely) with your doctor so your medication dosages can be changed if necessary or different medications can be prescribed that may be safer to take during pregnancy.
By preparing for pregnancy and following up regularly with your cardiologist during pregnancy, most women with a heart condition can safely become pregnant and have a healthy baby.
Preexisting cardiovascular conditions and pregnancy
Congenital heart conditions and pregnancy
Atrial (ASD) and ventricular septal defects (VSD), and patent ductus arteriosus (PDA) are the most common congenital heart defects. With these heart defects, there is an opening in the septum (the muscular wall separating the right and left side of the heart). If the hole is large, blood from the left side of the heart flows back into the right side of the heart and gets pumped back to the lungs again.
In general, most women with a congenital heart defect, especially those who have had corrective surgery, can safely become pregnant. However, the type of heart defect, severity of symptoms, presence of pulmonary hypertension or other cardiac or lung disease, and any prior heart surgeries may affect the outcome of the pregnancy. In some women who have a congenital heart defect and who also have pulmonary hypertension, pregnancy is not recommended, as there’s a high risk of maternal death.
Over time, symptoms of heart failure can occur or worsen in women with a congenital heart defect, increasing the mother’s risk of long-term complications.
There is a greater risk that the baby will develop a heart condition if either parent has a congenital heart defect. Your cardiologist may recommend a fetal echocardiogram to check the fetus’ 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 can provide you with guidance on the possible risks of pregnancy and can work with your health care team to monitor your health and your baby’s health during pregnancy.
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 (hypertrophy). Over time, symptoms of heart failure can occur or worsen, increasing the mother’s risk of long-term complications.
One common cause of aortic valve stenosis is bicuspid aortic valve disease, a congenital heart condition in which there are only two leaflets or cusps, instead of the normal three leaflets. 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 to correct the valve may be recommended before pregnancy.
Mitral valve stenosis means the mitral valve (the valve between the left atrium and left ventricle) is narrowed. This is often caused by rheumatic fever.
The increased blood volume and increased heart rate that occurs with pregnancy can worsen symptoms of mitral stenosis. The right atrium can enlarge in size causing a rapid irregular heart rhythm called atrial fibrillation. In addition, heart failure symptoms can occur (shortness of breath, irregular heart beat, fatigue and swelling or edema). This can increase the risk to the mother. Medications may be used during surgery, and in some cases, percutaneous valvuloplasty may be required during pregnancy to correct the narrowed valve. Patients with mitral stenosis need to have their valve evaluated prior to becoming pregnant. In some cases, surgery to correct the valve will be recommended before pregnancy.
Medications may be prescribed during pregnancy to reduce symptoms), and in some cases, percutaneous valvuloplasty may be required during pregnancy to correct the narrowed valve. Women with mitral valve stenosis need to be evaluated by a cardiologist before planning a pregnancy. In some cases, surgery to correct the valve may be recommended before pregnancy.
Mitral valve prolapse is a common condition, often not causing symptoms or requiring any treatment. Most patients with mitral valve prolapse tolerate pregnancy. If the prolapse causes a severe leak, treatment may be needed prior to pregnancy. It is always best to follow your doctor’s recommendations if you have mitral valve prolapse.
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 fetus. There is controversy regarding the best anticoagulant regimen.*
- During pregnancy, the risk of blood clots increases.
*Use of warfarin, heparin, aspirin, and combinations of these have been suggested and compared. The most recent recommendations from the European Heart Association suggest the use of heparin during first trimester followed by warfarin up to the 36th week of pregnancy, with subsequent replacement by heparin until delivery OR oral anticoagulation throughout pregnancy, until the 36th week, followed by heparin until delivery.
Warfarin doses are less harmful if the dose is kept to less than 5 mg. In addition, other specialists have recommended the addition of low dose aspirin for women at high risk. (4-6)
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 so you can discuss your potential risks and determine the best anticoagulant therapy.
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. They may develop for the first time during pregnancy in a woman with a normal heart or arrhythmias may be the result of a previously unknown heart condition. Most of the time, there are no symptoms of arrhythmias and no treatment is required. If symptoms develop, your doctor may order additional tests to determine the cause of the arrhythmias.
Learn more about arrhythmia and pregnancy
Aorta Disease and pregnancy
Women who have conditions affecting their aorta, such as aortic aneurysm, dilated aorta, or connective tissue disorders such as Marfan syndrome are at increased risk during pregnancy.
Increased pressures in the aorta during pregnancy and bearing down during labor and delivery can increase risk for aorta 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 the mother’s 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.
Cardiovascular disorders that may develop during pregnancy
Peripartum cardiomyopathy is the rare development of heart failure within the last month of pregnancy or within five months after delivery. The cause of peripartum cardiomyopathy remains unknown.
Women with peripartum cardiomyopathy have symptoms of heart failure. After pregnancy, the heart often returns to its normal size and function, although some women continue to have poor left ventricular function and symptoms. Women with peripartum cardiomyopathy have an increased risk for complications during subsequent pregnancies.
Hypertension (high blood pressure)
About 6 - 8 percent of women develop high blood pressure*, also called hypertension, during pregnancy. This is called Pregnancy-induced hypertension (PIH) and is related to preeclampsia, toxemia, or toxemia of pregnancy. PIH is a complication characterized by high blood pressure, swelling due to fluid retention, and protein in the urine. PIH can be harmful to the mother and the baby. To learn more about who is at risk for PIH, symptoms of PIH, and how PIH is diagnosed and treated, see the following links:
Sometimes, a heart murmur or abnormal “swishing” sound, can develop as a result of the increase in blood volume that occurs during pregnancy. In most cases, the murmur is harmless but in rare cases, it could mean there’s a problem with a heart valve. Your doctor can evaluate your condition and determine the cause of the murmur.
After you become pregnant
Congratulations on your pregnancy! During pregnancy, it’s important to:
In addition to keeping your follow-up appointments with your obstetric provider throughout pregnancy, schedule regular follow-up visits with your cardiologist and follow your cardiologist’s recommendations carefully. Your cardiologist can evaluate your heart condition throughout your pregnancy so symptoms and/or potential complications can be detected and treated early. This will help ensure a safe outcome for you and your baby.
Some conditions may require a team approach with the patient, obstetrician, cardiologist, anesthesiologist and pediatrician. Depending on the woman’s heart condition, special arrangements may need to be made for labor and delivery.
For more information
To make an appointment with a Cleveland Clinic women’s heart specialist, call toll-free 800.223.1696 or locally, 216.444.9353.
If you have any questions or need more information, call the Miller Family Heart & Vascular Institute Resource Center at 216.445.9288 or toll-free at 866.289.6911
- Siu S, Colman JM, Cardiovascular problems and pregnancy An approach to management, Cleveland Clinic Journal of Medicine, 2004; 71: 977-985.
- Prasad AK, Ventura HO, Valvular heart disease and pregnancy, Postgraduate Medicine2001; 110: 69-88.
- American Heart Association, Marfan Syndrome: View Article
- Nassar AH, Hobeika EM, Abd Essamad, HM, et. Al. Pregnancy outcome in women with prosthetic heart valves. American Journal of Obstetrics and Gynecology (2004) 191: 1009-13
- Gaasch WH, North RA, Management of pregnant women with prosthetic heart valves, UpToDate 4/15/2006.
- Butchart EG, Gohlke-Bärwolf C, Antunes MJ, Tornos P, DeCaterina R, Cormier B, Prendergast B, Lung B, Hans Bjornstad, Leport C, Hall RJC, Vahanian A, on behalf of the Working Groups on Valvular Heart Disease, Thrombosis, and Cardiac Rehabilitation and Exercise Physiology, European Society of Cardiology. Recommendations for the management of patients after heart valve surgery. ,European Heart Journal. 26: 2463-71.
- Pearson GD, Veille JC, Rahimtoola S, Hsia J, Oakley CM, Hosenpud JD, Ansari A, Baughman KL. Peripartum cardiomyopathy: National Heart, Lung, and Blood Institute and Office of Rare Diseases (National Institutes of Health) workshop recommendations and review. JAMA. 2000 Mar 1;283(9):1183-8.
- Samuel C. Siu, Mathew Sermer, Jack M. Colman, A. Nanette Alvarez, Lise-Andree Mercier, Brian C. Morton, Catherine M. Kells, M. Lynn Bergin, Marla C. Kiess, Francois Marcotte, Dylan A. Taylor, Elaine P. Gordon, John C. Spears, James W. Tam, Kofi S. Amankwah, Jeffrey F. Smallhorn, Dan Farine, and Sheryll Sorensen. Prospective Multicenter Study of Pregnancy Outcomes in Women With Heart Disease. Circulation 2001 104: 515 – 521.
- American Heart Association, Classification of Functional Capacity and Objective Assessment, View Article
- Maroo, Anjli and Russell Raymond. Pregnancy and Heart Disease. Cleveland Clinic Disease Management Program.
- American Heart Association, Pregnancy and Heart Disease, View Article
- American Heart Association, Effects of Heart Disease on Childbearing, View Article
- American Heart Association, Cardiac Ailments Acquired During Pregnancy, www.heart.org/HEARTORG/
Reviewed by Dr. Leslie Cho