Cardiovascular Disease in Pregnancy
Cardiovascular Disease in Pregnancy Definition Pregnancy places a significant burden on the heart, including changes in heart rate, blood pressure, blood volume, and the amount of blood pumped with each heartbeat. Therefore, heart (cardiovascular) diseases can develop or worsen during pregnancy. In pregnant women, heart disease is most severe when there is valve narrowing (stenosis), high blood pressure in the lungs (pulmonary hypertension), blood detoured from right to left within the heart (sh
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Cardiovascular Disease in Pregnancy Definition Pregnancy places a significant burden on the heart, including changes in heart rate, blood pressure, blood volume, and the amount of blood pumped with each heartbeat. Therefore, heart (cardiovascular) diseases can develop or worsen during pregnancy. In pregnant women, heart disease is most severe when there is valve narrowing (stenosis), high blood pressure in the lungs (pulmonary hypertension), blood detoured from right to left within the heart (shunting), and congestive heart failure (CHF). High blood pressure combined with a syndrome in which the heart beats too rapidly (Wolff-Parkinson-White syndrome) can be deadly during pregnancy. Rarely, heart enlargement and CHF (peripartum cardiomyopathy) develop in the final month of pregnancy or after delivery. Peripartum cardiomyopathy may be caused by viruses or a reaction of the body to infection (immune reaction). Incidence and Prevalence: The prevalence of heart disease among pregnant women is 0.3% to 3.5% ("Heart Diseases in Pregnancy") The pregnancy-induced changes in the cardiovascular system develop primarily to meet the increased metabolic demands of the mother and fetus. Changes in Cardiovascular System during pregnancy: Blood Volume increases progressively from 6-8 weeks gestation (pregnancy) and reaches a maximum at approximately 32-34 weeks with little change thereafter. Most of the added volume of blood is accounted for by an increased capacity of the uterine, breast, renal, striated muscle and cutaneous vascular systems, with no evidence of circulatory overload in the healthy pregnant woman. The increase in plasma volume (40-50%) is relatively greater than that of red cell mass (20-30%) resulting in hemodilution and a decrease in haemoglobin concentration. Intake of supplemental iron and folic acid is necessary to restore hemoglobin levels to normal (12 g/dl). The increased blood volume serves two purposes. First, it facilitates maternal and fetal exchanges of respiratory gases, nutrients and metabolites. Second, it reduces the impact of maternal blood loss at delivery. Typical losses of 300-500 ml for vaginal births and 7501000 ml for Caesarean sections are thus compensated with the so-called "autotransfusion" of blood from the contracting uterus. Blood Constituents. As mentioned above, red cell mass is increased 20-30%. Leukocyte counts are variable during gestation, but usually remain within the upper limits of normal. Marked elevations, however, develop during and after parturition (delivery). Fibrinogen, as well as total body and plasma levels of factors VII, X and XII increase markedly. The number of platelets also rises, yet not above the upper limits of normal. Combined with a decrease in fibrinolytic activity, these changes tend to prevent excessive bleeding at delivery. Thus, pregnancy is a relatively hypercoagulable state, but during pregnancy neither clotting or bleeding times are abnormal. Cardiac Output increases to a similar degree as the blood volume. During the first trimester cardiac output is 30-40% higher than in the non-pregnant state. Steady rises are shown on
Doppler echocardiography, from an average of 6.7 litres/minute at 8-11 weeks to about 8.7 litres/minute flow at 36-39 weeks; they are due, primarily, to an increase in stroke volume (35%) and, to a lesser extent, to a more rapid heart rate (15%). There is a steady reduction in systemic vascular resistance (SVR) which contributes towards the hyperdynamic circulation observed in pregnancy. During labor, further increases are seen with pain in response to increased catecholamine secretion; this increase can be blunted with the institution of labour analgesia. Also during labour, there is an increase in intravascular volume by 300-500 ml of blood from the contracting uterus to the venous system. Following delivery this autotransfusion compensates for the blood losses and tends to further increase cardiac output by 50% of pre-delivery values. At this point, stroke volume is increased while heart rate is slowed. Cardiac Size/Position/ECG. There are both size and position changes which can lead to changes in ECG appearance. The heart is enlarged by both chamber dilation and hypertrophy. Dilation across the tricuspid valve can initiate mild regurgitant flow causing a normal grade I or II systolic murmur. Upward displacement of the diaphragm by the enlarging uterus causes the heart to shift to the left and anteriorly, so that the apex beat is moved outward and upward. These changes lead to common ECG findings of left axis deviation, sagging ST segments and frequently inversion or flattening of the T-wave in lead III. Blood Pressure. Systemic arterial pressure is never increased during normal gestation. In fact, by midpregnancy, a slight decrease in diastolic pressure can be recognized. Pulmonary arterial pressure also maintains a constant level. Aortocaval Compression. From mid-pregnancy, the enlarged uterus compresses both the inferior vena cava and the lower aorta when the patient lies supine. Obstruction of the inferior vena cava reduces venous return to the heart leading to a fall in cardiac output by as much as 24% towards term. During the last trimester, maternal kidney function is markedly lower in the supine than in the lateral position. Furthermore, the fetus is compromised by insufficient transplacental gas exchange. Venous Distension increases approximately to 150% during the course of gestation and the venous ends of capillaries become dilated, causing reduced blood flow. These vascular changes contribute to delayed absorption of subcutaneously or intramuscularly injected substances. Clinical Implications. Despite the increased workload of the heart during gestation and labour, the healthy woman has no impairment of cardiac reserve. In contrast, for the gravida with heart disease and low cardiac reserve, the increase in the work of the heart may cause ventricular failure and pulmonary oedema. In these women, further increases in cardiac workload during labour must be prevented by effective pain relief, optimally provided by extradural or spinal analgesia. Since cardiac output is highest in the immediate postpartum period, sympathetic blockade should be maintained for several hours after delivery and then weaned off slowly. Teaching Point. There is a 30% reduction in volume of local anaesthetic solution required at term when compared to the non-pregnant woman, to achieve the same block.
Aortocaval compression and its sequelae must be avoided. No woman in late pregnancy should lie supine without shifting the uterus off the great abdomino-pelvic vessels. During labour, the parturient should rest on her side, left or right. During Caesarean section and for other indications demanding the supine position, the uterus should be displaced, usually to the left, by placing a rigid wedge under the right hip and/or tilting the table left side down. Diagnosis History: The individual may complain about shortness of breath; chest pain; heart fluttering (palpitations); episodic weakness; sweating; or swelling of the hands, legs, or feet. A past history of rheumatic fever, metabolic disease (e.g., diabetes mellitus), or serious infection (e.g., syphilis) could indicate possible predisposition to cardiovascular disease in pregnancy. Physical exam: Blood pressure is carefully monitored. During pregnancy, a third heart sound and a systolic functional murmur may be normal. The heart rate normally increases. Upon physical examination, the individual may present with blue skin (cyanosis); swollen (distended) veins; fluid in the lungs; coughing; breathing difficulty; and swelling of hands, legs, or feet. Tests: An electrocardiogram (ECG) may be done to look for changes in heart rhythm and an echocardiogram to examine the heart walls and internal structures of the heart. A chest x-ray is taken to check for fluid in the lungs and measure heart size. Lab tests also include CBC, coagulation studies, and chemistry panel. Fetal ultrasound may be done to measure growth and fetal weight. What cardiac ailments can be acquired during pregnancy? Some women with normal hearts experience cardiac "abnormalities" during pregnancy. Some of these are discussed here. Heart murmurs Doctor will often hear a heart murmur. This new sound is due to the extra blood flowing through your heart. Usually this doesn't mean anything is wrong with your heart. Rarely, however, a new murmur can mean that there's a problem with a heart valve. Arrhythmias Many people have fast or slow heartbeats that may be regular or irregular. These are called "arrhythmias." They can develop for the first time during pregnancy in a woman with a normal heart or as a result of previously unknown heart disease. Occasionally these arrhythmias are noticed when taking the pulse. Most often, there are no symptoms and no treatment is required. Sometimes arrhythmias do cause symptoms such as palpitations, dizziness or lightheadedness. On rare occasions they can even cause fainting. There can be other explanations for these symptoms, but if you have them, your doctor may want to check you for arrhythmias. Your doctor may also want to perform an ECG or have you wear a heart monitor for 24 hours to better understand your rhythm.
Again, most often you won't need treatment. If you do need treatment, your doctor will advise you about how it will affect you and your baby. High blood pressure High blood pressure (hypertension) is a serious complication of pregnancy. In a small number of cases, it’s present before pregnancy. However, about 8 percent of all pregnant women develop hypertension, most often after the 20th week. That's why you should have your blood pressure checked often all through your pregnancy. You should not take ACE inhibitors or ARB’s if you are pregnant or planning to become so. Very high blood pressure can occur, with a rapid weight gain, swollen ankles and protein in the urine. This disorder is knows as "toxemia of pregnancy" or "pre-eclampsia." It affects the blood vessels, kidneys, liver and brain. Decreased blood flow through the placenta also occurs in pre-eclampsia and can lead to slower growth in the uterus and loss of the fetus. Preeclampsia often necessitates a pre-term delivery. In fact, pre-eclampsia is the leading cause of premature birth in the United States. Pre-eclampsia is a serious complication of pregnancy. It requires immediate medical attention. It can progress to a life-threatening condition called eclampsia. Visual disturbances, severe headaches and abdominal pain usually precede eclampsia. Treatment Treatment aims for optimal health of the mother and fetus and preventive treatment is vital in pregnant individuals with heart disease. To help prevent cardiac decompensation, the individual must avoid overexertion. It is helpful to create a specific daily rest regimen (e.g., 10 hours/night in bed, scheduled morning and afternoon rest periods). After 20 weeks gestation, strenuous activities should be avoided. Antihypertensives, beta-blockers, or immunosuppressive drugs may be required to address associated symptoms. Anticoagulants may be used to prevent blood clots. Blood pressure, weight, and kidney function are closely monitored. Anemia is either prevented or treated. If surgery is required to repair the heart (e.g., dilation of the left atrioventricular valve [mitral valvotomy]), it is best done during the last 3 months (trimester) of pregnancy. In severe cases that threaten the woman's life, a therapeutic abortion or premature delivery by cesarean section may be considered. In all cases, careful consideration is given to the preferred method of delivery for the woman and fetus. Regular prenatal visits to a physician or maternity clinic are essential for a healthy, safe pregnancy, delivery and postpartum period. Prognosis Mild heart disease may resolve after delivery but can worsen and result in the death of the woman or fetus during labor or delivery. Peripartum cardiomyopathy may resolve or worsen after delivery, resulting in eventual heart failure and death. Cardiovascular disease may recur during future pregnancies. Mitral valvotomy has been successfully performed on pregnant individuals, but there is a high-risk of hypoxic damage to the fetus and placenta and a small risk of maternal operative mortality
Rehabilitation Rehabilitation addressing cardiovascular disease during pregnancy takes into account the major increase in blood volume imposed by the pregnancy. Pregnancy increases the blood volume by a full one-third. Rehabilitation professionals understand and are aware that this condition can predispose an individual to signs and symptoms of congestive heart failure. When administering the appropriate therapy, rehabilitation professionals work closely with a physician specializing in heart conditions (cardiologist). The individual's physical capacity determines the restrictions on her activities. Because activity is often limited, the physical therapist initiates range of motion exercises to return mobility to joints and stretch key muscles so as not to place stress on the cardiovascular system. Depending on the severity of the disease, the individual may be required to follow certain dietary restrictions (e.g., lowering salt intake). It should also be noted that adequate rest is of utmost importance. Once the pregnancy is full term and the child is born, rehabilitation proceeds, as tolerated, with postpartum (after-birth) precautions and considerations. When the individual's strength and endurance reach an appropriate level recommended by the cardiologist, activity in the form of mild exercise can begin under the supervision of a healthcare professional. Complications Blood clots can form and lodge in the veins, lungs, heart, or brain. The brain, heart muscle, liver, or kidneys may be damaged, resulting in hypertensive encephalopathy, stroke (cardiovascular accident), eclampsia, or kidney or heart failure. The lungs may fill with fluid (pulmonary edema). The main vessel in the abdomen or vessels supplying the heart may burst (dissecting aneurysm). Infection of the sac surrounding the heart (pericarditis) can also occur. Drugs or other treatments can adversely affect the fetus and must be chosen with extreme care Return to Work (Restrictions / Accommodations) There may be mild to moderate restrictions on activity due to fatigue and anxiety. Work restrictions may include transfer to a sedentary job, elimination of strenuous work (especially heavy lifting), and an increased number of rest periods. The individual should avoid fumes, radiation, and chemical exposure. In certain cases, pregnancies complicated by heart disease will require complete work cessation. Failure to Recover If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.
AHA Recommendation 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. If you have a heart condition, you and your healthcare provider need to talk about it and plan for your pregnancy. You'll also need to think about what may be involved in caring for your child later. Here are 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.
Doppler echocardiography, from an average of 6.7 litres/minute at 8-11 weeks to about 8.7 litres/minute flow at 36-39 weeks; they are due, primarily, to an increase in stroke volume (35%) and, to a lesser extent, to a more rapid heart rate (15%). There is a steady reduction in systemic vascular resistance (SVR) which contributes towards the hyperdynamic circulation observed in pregnancy. During labor, further increases are seen with pain in response to increased catecholamine secretion; this increase can be blunted with the institution of labour analgesia. Also during labour, there is an increase in intravascular volume by 300-500 ml of blood from the contracting uterus to the venous system. Following delivery this autotransfusion compensates for the blood losses and tends to further increase cardiac output by 50% of pre-delivery values. At this point, stroke volume is increased while heart rate is slowed. Cardiac Size/Position/ECG. There are both size and position changes which can lead to changes in ECG appearance. The heart is enlarged by both chamber dilation and hypertrophy. Dilation across the tricuspid valve can initiate mild regurgitant flow causing a normal grade I or II systolic murmur. Upward displacement of the diaphragm by the enlarging uterus causes the heart to shift to the left and anteriorly, so that the apex beat is moved outward and upward. These changes lead to common ECG findings of left axis deviation, sagging ST segments and frequently inversion or flattening of the T-wave in lead III. Blood Pressure. Systemic arterial pressure is never increased during normal gestation. In fact, by midpregnancy, a slight decrease in diastolic pressure can be recognized. Pulmonary arterial pressure also maintains a constant level. Aortocaval Compression. From mid-pregnancy, the enlarged uterus compresses both the inferior vena cava and the lower aorta when the patient lies supine. Obstruction of the inferior vena cava reduces venous return to the heart leading to a fall in cardiac output by as much as 24% towards term. During the last trimester, maternal kidney function is markedly lower in the supine than in the lateral position. Furthermore, the fetus is compromised by insufficient transplacental gas exchange. Venous Distension increases approximately to 150% during the course of gestation and the venous ends of capillaries become dilated, causing reduced blood flow. These vascular changes contribute to delayed absorption of subcutaneously or intramuscularly injected substances. Clinical Implications. Despite the increased workload of the heart during gestation and labour, the healthy woman has no impairment of cardiac reserve. In contrast, for the gravida with heart disease and low cardiac reserve, the increase in the work of the heart may cause ventricular failure and pulmonary oedema. In these women, further increases in cardiac workload during labour must be prevented by effective pain relief, optimally provided by extradural or spinal analgesia. Since cardiac output is highest in the immediate postpartum period, sympathetic blockade should be maintained for several hours after delivery and then weaned off slowly. Teaching Point. There is a 30% reduction in volume of local anaesthetic solution required at term when compared to the non-pregnant woman, to achieve the same block.
Aortocaval compression and its sequelae must be avoided. No woman in late pregnancy should lie supine without shifting the uterus off the great abdomino-pelvic vessels. During labour, the parturient should rest on her side, left or right. During Caesarean section and for other indications demanding the supine position, the uterus should be displaced, usually to the left, by placing a rigid wedge under the right hip and/or tilting the table left side down. Diagnosis History: The individual may complain about shortness of breath; chest pain; heart fluttering (palpitations); episodic weakness; sweating; or swelling of the hands, legs, or feet. A past history of rheumatic fever, metabolic disease (e.g., diabetes mellitus), or serious infection (e.g., syphilis) could indicate possible predisposition to cardiovascular disease in pregnancy. Physical exam: Blood pressure is carefully monitored. During pregnancy, a third heart sound and a systolic functional murmur may be normal. The heart rate normally increases. Upon physical examination, the individual may present with blue skin (cyanosis); swollen (distended) veins; fluid in the lungs; coughing; breathing difficulty; and swelling of hands, legs, or feet. Tests: An electrocardiogram (ECG) may be done to look for changes in heart rhythm and an echocardiogram to examine the heart walls and internal structures of the heart. A chest x-ray is taken to check for fluid in the lungs and measure heart size. Lab tests also include CBC, coagulation studies, and chemistry panel. Fetal ultrasound may be done to measure growth and fetal weight. What cardiac ailments can be acquired during pregnancy? Some women with normal hearts experience cardiac "abnormalities" during pregnancy. Some of these are discussed here. Heart murmurs Doctor will often hear a heart murmur. This new sound is due to the extra blood flowing through your heart. Usually this doesn't mean anything is wrong with your heart. Rarely, however, a new murmur can mean that there's a problem with a heart valve. Arrhythmias Many people have fast or slow heartbeats that may be regular or irregular. These are called "arrhythmias." They can develop for the first time during pregnancy in a woman with a normal heart or as a result of previously unknown heart disease. Occasionally these arrhythmias are noticed when taking the pulse. Most often, there are no symptoms and no treatment is required. Sometimes arrhythmias do cause symptoms such as palpitations, dizziness or lightheadedness. On rare occasions they can even cause fainting. There can be other explanations for these symptoms, but if you have them, your doctor may want to check you for arrhythmias. Your doctor may also want to perform an ECG or have you wear a heart monitor for 24 hours to better understand your rhythm.
Again, most often you won't need treatment. If you do need treatment, your doctor will advise you about how it will affect you and your baby. High blood pressure High blood pressure (hypertension) is a serious complication of pregnancy. In a small number of cases, it’s present before pregnancy. However, about 8 percent of all pregnant women develop hypertension, most often after the 20th week. That's why you should have your blood pressure checked often all through your pregnancy. You should not take ACE inhibitors or ARB’s if you are pregnant or planning to become so. Very high blood pressure can occur, with a rapid weight gain, swollen ankles and protein in the urine. This disorder is knows as "toxemia of pregnancy" or "pre-eclampsia." It affects the blood vessels, kidneys, liver and brain. Decreased blood flow through the placenta also occurs in pre-eclampsia and can lead to slower growth in the uterus and loss of the fetus. Preeclampsia often necessitates a pre-term delivery. In fact, pre-eclampsia is the leading cause of premature birth in the United States. Pre-eclampsia is a serious complication of pregnancy. It requires immediate medical attention. It can progress to a life-threatening condition called eclampsia. Visual disturbances, severe headaches and abdominal pain usually precede eclampsia. Treatment Treatment aims for optimal health of the mother and fetus and preventive treatment is vital in pregnant individuals with heart disease. To help prevent cardiac decompensation, the individual must avoid overexertion. It is helpful to create a specific daily rest regimen (e.g., 10 hours/night in bed, scheduled morning and afternoon rest periods). After 20 weeks gestation, strenuous activities should be avoided. Antihypertensives, beta-blockers, or immunosuppressive drugs may be required to address associated symptoms. Anticoagulants may be used to prevent blood clots. Blood pressure, weight, and kidney function are closely monitored. Anemia is either prevented or treated. If surgery is required to repair the heart (e.g., dilation of the left atrioventricular valve [mitral valvotomy]), it is best done during the last 3 months (trimester) of pregnancy. In severe cases that threaten the woman's life, a therapeutic abortion or premature delivery by cesarean section may be considered. In all cases, careful consideration is given to the preferred method of delivery for the woman and fetus. Regular prenatal visits to a physician or maternity clinic are essential for a healthy, safe pregnancy, delivery and postpartum period. Prognosis Mild heart disease may resolve after delivery but can worsen and result in the death of the woman or fetus during labor or delivery. Peripartum cardiomyopathy may resolve or worsen after delivery, resulting in eventual heart failure and death. Cardiovascular disease may recur during future pregnancies. Mitral valvotomy has been successfully performed on pregnant individuals, but there is a high-risk of hypoxic damage to the fetus and placenta and a small risk of maternal operative mortality
Rehabilitation Rehabilitation addressing cardiovascular disease during pregnancy takes into account the major increase in blood volume imposed by the pregnancy. Pregnancy increases the blood volume by a full one-third. Rehabilitation professionals understand and are aware that this condition can predispose an individual to signs and symptoms of congestive heart failure. When administering the appropriate therapy, rehabilitation professionals work closely with a physician specializing in heart conditions (cardiologist). The individual's physical capacity determines the restrictions on her activities. Because activity is often limited, the physical therapist initiates range of motion exercises to return mobility to joints and stretch key muscles so as not to place stress on the cardiovascular system. Depending on the severity of the disease, the individual may be required to follow certain dietary restrictions (e.g., lowering salt intake). It should also be noted that adequate rest is of utmost importance. Once the pregnancy is full term and the child is born, rehabilitation proceeds, as tolerated, with postpartum (after-birth) precautions and considerations. When the individual's strength and endurance reach an appropriate level recommended by the cardiologist, activity in the form of mild exercise can begin under the supervision of a healthcare professional. Complications Blood clots can form and lodge in the veins, lungs, heart, or brain. The brain, heart muscle, liver, or kidneys may be damaged, resulting in hypertensive encephalopathy, stroke (cardiovascular accident), eclampsia, or kidney or heart failure. The lungs may fill with fluid (pulmonary edema). The main vessel in the abdomen or vessels supplying the heart may burst (dissecting aneurysm). Infection of the sac surrounding the heart (pericarditis) can also occur. Drugs or other treatments can adversely affect the fetus and must be chosen with extreme care Return to Work (Restrictions / Accommodations) There may be mild to moderate restrictions on activity due to fatigue and anxiety. Work restrictions may include transfer to a sedentary job, elimination of strenuous work (especially heavy lifting), and an increased number of rest periods. The individual should avoid fumes, radiation, and chemical exposure. In certain cases, pregnancies complicated by heart disease will require complete work cessation. Failure to Recover If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.
AHA Recommendation 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. If you have a heart condition, you and your healthcare provider need to talk about it and plan for your pregnancy. You'll also need to think about what may be involved in caring for your child later. Here are 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.
