INTRODUCTION — Although cardiac disease complicates a small percentage of all pregnancies in developed countries (eg, only 1 to 4 percent of pregnancies in the United States), maternal cardiac disease is a major cause of non-obstetric maternal morbidity and mortality (figure 1). Care of high-risk patients requires a team approach including a maternal-fetal medicine specialist, cardiologist, and obstetrical anesthesiologist.
In the past, rheumatic heart disease was the most common form of cardiac disease in pregnant women; it still predominates in developing countries and in immigrant populations in the United States. Congenital heart disease is now the most common form of heart disease complicating pregnancy in the United States, in part because advances in the treatment of congenital heart disease have made it possible for more affected children to reach adulthood and attempt pregnancy. (See "Pregnancy in women with congenital heart disease: General principles" and "Pregnancy and Marfan syndrome".)
In addition, many women are postponing childbearing until the fourth and fifth decades of life [1,2]; with advancing maternal age, underlying medical conditions such as hypertension, diabetes, and hypercholesterolemia become more common and increase the incidence of acquired heart disease complicating pregnancy.
This topic will discuss the risk assessment and management of pregnant women with acquired heart disease. Valvular heart disease and congenital heart disease in pregnant women are discussed separately. (See "Pregnancy and valve disease" and "Pregnancy in women with congenital heart disease: General principles".)
PHYSIOLOGY OF NORMAL PREGNANCY — Pregnancy is associated with several cardiocirculatory changes that can significantly impact underlying cardiac disease. These changes begin early in pregnancy (within the first five to eight weeks), reach their peak during the late second trimester, and then remain relatively constant until delivery [3]. Knowledge of these cardiovascular adaptations is required to correctly interpret hemodynamic and cardiovascular tests during pregnancy, labor, and delivery; to predict the effects of pregnancy on the woman with underlying cardiac disease; and to understand how the fetus will be affected by maternal cardiac disorders. There are changes in cardiac output, blood pressure, systemic vascular resistance, heart rate, and changes in blood volume which may have a significant impact on a pregnancy depending on the underlying cardiac disease, as discussed separately. (See "Maternal adaptations to pregnancy: Cardiovascular and hemodynamic changes".)
Physical examination — Normal physical findings may include prominent distended neck veins related to the increased blood volume and compression of the IVC, basilar rales due to an elevated diaphragm, a prominent but not displaced left and right ventricular apical impulse due to the increased blood volume and cardiac output, exaggerated heart sounds, and a new systolic ejection flow murmur best heard over the mid or lower left sternal border. Preexisting murmurs will be louder. A physiologic S3 gallop may be appreciated in a young patient but would be abnormal in a 40 year old woman. Peripheral edema will be present in the last trimester due to the increased blood volume and IVC compression. One of the challenges for the clinician is how to distinguish between these normal signs of pregnancy and similar signs that may indicate underlying heart disease (eg, heart failure, constrictive pericarditis) in the mother. The maternal cardiac evaluation is discussed in detail separately. (See "Maternal adaptations to pregnancy: Cardiovascular and hemodynamic changes", section on 'Physical examination'.)
Electrocardiographic changes — The surface electrocardiogram may exhibit subtle changes during normal pregnancy as discussed separately. (See "Maternal adaptations to pregnancy: Cardiovascular and hemodynamic changes", section on 'Electrocardiogram'.)
ASSESSING RISK
Predictors of cardiac events — Women with acquired heart disease are at risk for cardiac complications during pregnancy. Their risk can be assessed by evaluating the severity of their valve lesions and the degree of ventricular dysfunction. The history, physical examination, echocardiogram, and electrocardiogram form the foundation of cardiac evaluation in all patients.
A commonly used risk assessment tool is CARPREG II, which is based on data from 1938 pregnancies in two large Canadian hospitals [4]. In the study population, 63.7 percent of patients had congenital heart disease, 22.9 percent had acquired heart disease, and 13.4 percent had isolated cardiac arrhythmias. 13.6 percent had at least mild left ventricular systolic function and 2 percent had coronary artery disease.
The CARPREG II risk score includes 10 predictors of risk for the development of cardiac complications.
●Five are general predictors; prior cardiac events or arrhythmias (3 points), poor functional class or cyanosis (3 points), high risk valve disease or LVOT obstruction (2 points), systemic ventricular dysfunction defined as an ejection fraction less than 55 percent (2 points) and no prior cardiac intervention (1 point).
●Four are lesion specific predictors; mechanical valves (3 points), high-risk aortopathy with aortic dimension >45 mm (2 points), pulmonary hypertension (2 points) and coronary artery disease (2 points).
●The one delivery of care predictor is late pregnancy assessment (1 point).
Cardiac complications, primarily arrhythmias and heart failure, occurred in 16 percent of the study patients. The risk of a primary cardiac event was 5 percent for 0-1 point, 10 percent for 2 points, 15 percent for 3 points, 22 percent for 4 points, and 41 percent for >4 points. Each WHO class included a wide range of cardiac event rates, and the CARPREG II risk score further stratified risk with each modified WHO class.
Brain natriuretic peptide — Patients with known cardiac disease and those with severe chronic hypertension should have a baseline BNP drawn. For patients with a change in clinical status, a repeat BNP that shows a significant change would suggest decompensation.
BNP levels in healthy women increase approximately twofold during pregnancy [5] but are lower than the levels observed in patients with heart failure [6]. Normal levels of natriuretic peptides may be useful in excluding cardiac decompensation in pregnancy [6,7].
A prospective study from Toronto evaluated BNP levels during pregnancy in 66 women with heart disease and 12 healthy women; those with heart disease had significantly higher BNP levels than those without heart disease (median 79 versus 35 pg/mL) [6]. A BNP >100 pg/mL was measured in all eight women with an adverse maternal cardiac event during pregnancy; in seven of these women, the BNP >100 pg/mL measurement was obtained prior to or at the time of decompensation. However, a BNP >100 pg/mL was also observed in 16 of 55 women with heart disease without clinical events.
The ZAHARA II investigators conducted a national, prospective, multicenter cohort study in pregnant women with congenital heart disease and showed that an N-terminal pro-B-type natriuretic peptide level >128 pg/mL at 20 weeks gestation was an independent predictor of adverse cardiovascular events, which included heart failure, need for an urgent cardiovascular procedure, significant arrhythmias, and other cardiovascular events [7].
CARDIOMYOPATHY — Women in their childbearing years may present with ventricular dysfunction from a number of etiologies: prior viral infection, HIV infection, peripartum cardiomyopathy, or drug-induced cardiomyopathy (eg, cocaine, doxorubicin). In one study, heart failure, arrhythmias, and stroke were more common in women whose left ventricular ejection fraction was less than 40 percent [8]. (See "Causes of dilated cardiomyopathy" and "Peripartum cardiomyopathy: Etiology, clinical manifestations, and diagnosis".)
There is insufficient information to determine whether pregnancy might be better tolerated in some groups than in others based upon the etiology of the cardiomyopathy. A study of 26 women from Brazil suggested that cardiac complications were higher in the idiopathic group than in the group with peripartum cardiomyopathy and persistent left ventricular dysfunction [9]. In contrast, a study of 31 women from the United States came to the opposite conclusion; maternal outcomes were worse in the peripartum group than in the idiopathic group [10]. A study from Haiti identified 99 women with peripartum cardiomyopathy, 15 of whom had subsequent pregnancies. Eight of these women experienced worsening heart failure and long-term systolic dysfunction [11].
A study from Toronto evaluated rates of maternal cardiac events and adverse fetal and neonatal events in 36 pregnancies in 32 women with dilated cardiomyopathy [12]:
●14 (39 percent) pregnancies were complicated by at least one maternal cardiac event. All maternal cardiac events occurred in women with moderate or severe LV systolic dysfunction (defined as left ventricular ejection fraction [LVEF] <45 percent) and/or New York Heart Association (NYHA) functional class III or IV and/or a prior cardiac event. The presence of any one of these three risk factors was associated with a 64 percent risk of an adverse cardiac event.
●The 16 month event-free survival for a subset of 18 pregnant women with LVEF <45 percent was significantly worse compared with 18 age and LVEF-matched nonpregnant women with dilated cardiomyopathy (28 versus 83 percent).
●Seven of 35 (20 percent) pregnancies (excluding one pregnancy ending in induced abortion) were complicated by an adverse fetal and/or neonatal event. The adverse neonatal event rate was highest among women with both obstetric and cardiac risk factors.
Patients with known or suspected left ventricular dysfunction should have an echocardiogram before conception, or as soon as possible after pregnancy is confirmed, to determine baseline ventricular function. Pregnancy should be discouraged if there is a significant reduction in ventricular function (ejection fraction <45 percent). Of concern, women with prior peripartum cardiomyopathy in whom left ventricular function has returned to normal (≥50 percent) still remain at significant risk for morbidity during subsequent pregnancies [13].
Patients with reduced ventricular function may require restriction of activity, medication (eg, digoxin, diuretics, vasodilators), and close monitoring during labor and delivery to avoid significant volume shifts. (See "Management of heart failure during pregnancy".)
Pregnancy is generally well tolerated in women with hypertrophic cardiomyopathy (HCM) [14-16]. A study from Italy showed that the risk of death in patients with hypertrophic cardiomyopathy is increased over that of the general population, although the absolute mortality is low [16]. Clinical deterioration with development of congestive heart failure occurred in 15 percent of the cohort and was related to their functional status prior to pregnancy. (See "Hypertrophic cardiomyopathy: Medical management for non-heart failure symptoms", section on 'HCM during pregnancy and delivery'.)
CORONARY ARTERY DISEASE — There is little published information about the optimal management of pregnant women with pre-existing coronary artery disease (CAD). This would include women with a history of prior myocardial infarction (MI), percutaneous coronary interventions, spontaneous coronary artery dissection, coronary artery bypass surgery, and CAD from a systemic process such as vasculitis. This population is likely to increase, given that the only increase in birth rate in 2009 occurred in women aged 40 to 44 [17].
A retrospective study from Canada and several European countries looked at adverse maternal cardiac, obstetric, and fetal/neonatal events in women with a pre-existing history of CAD or acute coronary syndrome (ACS) including MI; patients with Kawasaki disease and anomalous coronary arteries without ischemic events were excluded [18]. Ten percent of the patients had a primary cardiac event (cardiac arrest/ventricular arrhythmia, ACS/MI, or heart failure). Twenty-six percent had ischemic cardiac events (new or progressive angina, ACS/MI, ventricular arrhythmia, or cardiac arrest). Adverse obstetric outcomes occurred in 16 percent, and 30 percent were complicated by an adverse fetal/neonatal event.
For women with a history of CAD, it is recommended that prior to pregnancy, baseline left ventricular function should be determined, and stress testing may be beneficial to rule out active ischemia. It is currently recommended that medications, including lipid-lowering therapy, angiotensin converting enzyme inhibitors, and antiplatelet agents such as clopidogrel, be discontinued. However, cessation of lipid lowering therapy might impact unfavorably on prior coronary interventions and on lipid profiles during pregnancy, especially in young women with familial lipid problems. There are some data to suggest that lipid lowering therapy may not be as teratogenic as originally thought. One observational cohort study looking at the risk of malformations in a group of women exposed to lipid lowering drugs in the first trimester compared with a group without exposure showed no difference in the rate of malformations [19]. Pravastatin is being considered as a potential therapy for the prevention of pre-eclampsia in high-risk pregnant women [20]. For high risk CAD patients taking clopidogrel, the drug could be used during pregnancy if needed, although the drug should be stopped prior to delivery to minimize bleeding. Most patients will be taking low dose aspirin which should be continued [21].
MYOCARDIAL INFARCTION — Acute myocardial infarction is a rare event in pregnancy and some women with a prior infarction become pregnant. The management of these patients is discussed separately. (See "Acute myocardial infarction and pregnancy".)
HEART TRANSPLANT RECIPIENTS — Successful pregnancies have been reported in heart transplant recipients [22-24]. The management of medications such as cyclosporine and antihypertensive drugs requires the expertise of a transplant service. This issue is discussed in detail separately. (See "Heart transplantation in adults: Pregnancy after transplantation".)
ARRHYTHMIAS — Arrhythmias and conduction disturbances can antedate or originate during pregnancy and may be exacerbated by it. Potential factors in pregnancy that can promote arrhythmogenesis include the hyperdynamic state (high cardiac output, increased contractility), the altered hormonal milieu, and underlying heart disease [25].
A study showed that recurrence of arrhythmias in women with preexisting rhythm disorders is common and that recurrence of arrhythmias increases the risk of adverse fetal complications [26]. (See "Supraventricular arrhythmias during pregnancy" and "Ventricular arrhythmias during pregnancy".)
MANAGEMENT OF LABOR AND DELIVERY — Management of labor and delivery for gravidas with heart disease requires collaborative management by obstetricians, cardiologists, neonatologists, and anesthesiologists [27].
Anesthesia/analgesia — Intramuscular or intravenous opiates may be used to relieve pain and apprehension, but are not highly effective. Lumbar epidural anesthesia is highly effective for controlling labor pain and is recommended because it lowers pain-induced elevations of sympathetic activity, reduces the urge to push, and provides excellent anesthesia for operative procedures. The epidural should be dosed slowly with epidural solution (eg, local anesthetic plus opioid) to maintain stable hemodynamics and adequate uteroplacental blood flow since venous return can be reduced by the anesthetic. Intravenous fluid administration must be monitored carefully to avoid over or under hydration. (See "Anesthesia for labor and delivery in high-risk heart disease: General considerations".)
Hemodynamic monitoring — Systemic arterial pressure and heart rate are routinely monitored during labor; pulse oximetry and continuous electrocardiogram (ECG) monitoring are utilized as required by the patient's condition. A Swan-Ganz catheter for hemodynamic monitoring should not be routinely employed. (See "Pulmonary artery catheterization: Indications, contraindications, and complications in adults".)
Mode and timing of delivery — For nearly all gravidas with cardiac disease, vaginal delivery is preferred to cesarean delivery since vaginal delivery generally poses less cardiac risk. Cesarean delivery is generally reserved for obstetric indications. However, urgent cesarean delivery is suggested for gravidas with advanced heart failure and hemodynamic instability despite treatment [27].
Cesarean delivery should generally be reserved for obstetric indications such as failure to progress in labor, placenta previa, or fetal intolerance to labor. The concerns about cesarean delivery include:
●General anesthesia, if required, incurs the risk of hemodynamic instability associated with intubation and the anesthetic agent.
●Cesarean delivery is accompanied by blood loss that is approximately twice as great as with vaginal delivery.
●There are increased risks of wound and uterine infection.
●Postoperative thrombophlebitis is more common after cesarean delivery.
●The risk of postoperative incisional bleeding is high in patients requiring anticoagulants.
Spontaneous onset of labor is preferred to induced labor for most women with heart disease [27]. Pregnant women with cardiac disease who are considered functionally normal or well-controlled should be allowed to go into labor spontaneously. If there are any concerns about the functional adequacy of the heart and circulation, induction of labor under controlled conditions is suggested. A planned daytime induction is the most practical. The timing of induction is individualized, taking into account the gravida's cardiac status, inducibility of the cervix, and fetal lung maturity. A long induction in a woman with an unfavorable cervix should be avoided. From a practical point of view, it may be useful to plan the induction so that delivery occurs during the working day when all hospital services are readily available.
Induction of labor in a gravida with a favorable cervix usually requires only oxytocin administration and artificial rupture of the membranes. An unfavorable cervix should be ripened with a prostaglandin E analogue. The softened, dilated cervix is more responsive to subsequent induction of labor and permits the normal physiologic sequence of softening and dilatation before the onset of uterine contractions. Prostaglandin analogues are absorbed into the systemic circulation and can lower systemic vascular resistance, lower systemic pressure, and increase heart rate [28]. These effects are more frequent with E2 than E1 and when the drugs are used in the higher doses required for termination of pregnancy. Laminaria or a Foley catheter balloon can also be used for cervical ripening. (See "Induction of labor with oxytocin".)
Once in labor, the woman should be placed in a lateral decubitus position to attenuate the hemodynamic fluctuations associated with major uterine contractions and the supine position. The obstetrician should allow uterine contraction to descend the fetal head to the perineum, unassisted by maternal pushing, to avoid the undesirable circulatory effects of the Valsalva maneuver. Delivery may then be assisted by low forceps or vacuum extraction, as needed.
Fetal monitoring — A reduction in uterine blood flow and placental oxygen delivery typically occurs during uterine contractions; however, the fetus is adapted to extract enough oxygen to maintain fetal health. Complications of labor (eg, abruption, cord compression) or maternal hemodynamic instability may subject the fetus to decreased oxygenation and lead to fetal acidosis or death. The growth restricted fetus is especially vulnerable to hypoxia during labor. For this reason, continuous electronic fetal heart rate monitoring is recommended to assess fetal well-being during labor and allow timely intervention if nonreassuring fetal heart rate patterns occur [29]. (See "Nonstress test and contraction stress test".)
Antibiotic prophylaxis — The role of antibiotic prophylaxis for endocarditis is discussed separately.
Postpartum care — Prevention and management of severe postpartum blood loss is discussed in detail separately. (See "Overview of postpartum hemorrhage" and "Postpartum hemorrhage: Medical and minimally invasive management" and "Postpartum hemorrhage: Management approaches requiring laparotomy" and "Postpartum hemorrhage: Use of intrauterine tamponade to control bleeding".)
Delivery is associated with hemodynamic changes that can lead to heart failure in women with preexisting cardiovascular disease (see "Maternal adaptations to pregnancy: Cardiovascular and hemodynamic changes"). As a result, hemodynamic monitoring of the mother is warranted for 12 to 24 hours after delivery [30].
In patients requiring prolonged bed rest, meticulous leg care, elastic support stockings, and early ambulation are important preventive measures that reduce the risk of thromboembolism postpartum.
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Management of cardiovascular diseases during pregnancy".)
SUMMARY AND RECOMMENDATIONS
●Although cardiac disease complicates only 1 to 4 percent of all pregnancies in the United States, maternal cardiac disease is a major cause of non-obstetric maternal morbidity and mortality. Care of the high-risk patients requires a team approach including a maternal-fetal medicine specialist, cardiologist, and obstetrical anesthesiologist. (See 'Introduction' above.)
●Risk assessment of the patient with cardiac disease should be done using clinical, electrocardiographic, and echocardiographic data. A commonly used risk assessment tool is CARPREG II. The modified WHO classification can also be used to predict risk.
●An elevated brain natriuretic peptide (BNP) during pregnancy has been shown to be a predictor of cardiovascular events. BNP levels should be interpreted in the clinical context during pregnancy, as levels generally increase approximately twofold during uncomplicated pregnancy. A negative BNP is helpful to exclude heart failure. (See 'Brain natriuretic peptide' above.)
●Women in their childbearing years may present with ventricular dysfunction from a number of etiologies: prior viral infection, HIV infection, peripartum cardiomyopathy, or drug-induced cardiomyopathy (eg, cocaine, doxorubicin). (See 'Cardiomyopathy' above.)
●Women with prior peripartum cardiomyopathy in whom left ventricular function has returned to normal still remain at significant risk for morbidity during subsequent pregnancies. (See 'Cardiomyopathy' above.)
●Most gravidas with cardiac disease can expect to attempt vaginal delivery because it poses less cardiac risk than cesarean delivery. Cesarean delivery should be reserved for standard obstetric indications such as failure to progress in labor, placenta previa, or fetal intolerance to labor. (See 'Mode and timing of delivery' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Michael R. Foley, MD, who contributed to an earlier version of this topic review.
