INTRODUCTION
Cardiac disease is a leading cause of morbidity and mortality in pregnant women.
1 An increased prevalence of cardiovascular disease (
CVD) has been found in women of childbearing age, in which the responsibility of the treating physician extends to the unborn fetus. As a result, care of these high-risk patients often requires a team approach including specialists in maternal-fetal medicine, cardiology, and obstetric anesthesiology. The body undergoes significant amounts of physiologic changes during this period of time, and the underlying cardiac disease can affect both the mother and the fetus. Cardiac medications are usually needed for one out of three women with
CVD and may have side effects that lead to additional fetal risks. This chapter will review the epidemiology and risk factors of cardiac disease in pregnancy, the physiologic cardiovascular changes that occur with pregnancy, and the management of pregnant women with various cardiovascular conditions.
Epidemiology
Historically, rheumatic heart disease was the most common form of cardiac disease encountered in pregnant women. It continues to be prevalent in developing countries, but more recently, congenital heart disease has become the most common form of heart disease complicating pregnancy in the United States. Mortality has been increasing throughout the years for women in pregnancy, with a maternal mortality of approximately 1%-2% of pregnancies.
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3 It increased from 9.1 deaths per 100,000 live births in 1987-1990 to 11.5 deaths in 1991-1997 to 14.5 deaths in 1998-2005 and to 16.0 deaths per 100,000 live births in 2006-2010. According to national data from 2006 to 2010, cardiovascular conditions and cardiomyopathy resulted in 15.5% and 11.0% of these deaths, respectively. In 2011 to 2013, the mortality further increased to approximately 17.0 deaths per 100,000 live births in women with pregnancies,
4 with 43.5 deaths in black women, 12.7 deaths in white women, and 14.4 deaths in women of other races per 100,000 live births.
Approximately 40.5% of deaths from pregnancy are from cardiac-related conditions such as cardiomyopathy,
CVD, and hypertensive disorders. Some of the adverse events seen in pregnant women with hypertension include fetal growth restriction (4%), placental abruption (1%), and preterm delivery (26%).
5 For women with known cardiomyopathy with symptomatic heart failure from congenital heart disease, primary cardiac events occurred in 13%, fetuses small for gestational age in 20%, and fetal and neonatal death in 2% of the pregnancies.
6Cardiac disease complicates about 1%-4% of all pregnancies in the developed world and is a major cause of nonobstetric morbidity and mortality.
7 Because of advances in medical care, increasing numbers of women with congenital and acquired heart disease are becoming pregnant and delivering safely. Hypertensive disease is the most common cardiovascular disorder in pregnancy occurring in 5%-10% cases. With the development of advanced medical and surgical therapies, more than 85% of children with congenital heart disease are expected to reach adulthood. Naturally, a greater number of women with underlying congenital heart disease are becoming pregnant. However, in the developing world, rheumatic heart disease is still a significant contributor to maternal morbidity and mortality in pregnant women.
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Risk Factors
Women with cardiac disease are at a higher risk of cardiovascular and neonatal complications during their pregnancy.
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10 The morbidity and mortality risks of the mother and the neonate will depend on the severity of the cardiac condition.
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12 Some of these complications include preterm labor, preeclampsia, miscarriage, intrauterine fetal death, and postpartum hemorrhage
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13 Arrhythmias and heart failure may also manifest during pregnancy in women with cardiac disease.
11In the Western world, women are increasingly having children later in life. With advanced maternal age, the incidence of acquired cardiovascular risk factors increases, including diabetes, hypertension, hyperlipidemia, coronary artery disease, and obesity. These comorbidities can complicate pregnancy and lead to poor maternal and neonatal outcomes.
1For healthy women without a history of cardiovascular or congenital heart disease, the chance of their offspring having congenital heart disease is 1 in 100. However, if either of the parents has congenital heart disease, then the risk of them passing it to their children ranges from 3% to 50% depending on their particular cardiac defect.
1,
14 For first-degree relatives of individuals with
CHD, the prevalence of congenital heart disease in their children is approximately 1%-5%. Hence, pregnant women who have family members with congenital heart disease are often referred for a fetal echocardiogram.
Risk factors for coronary artery disease, such as drug use, alcohol use, smoking, diabetes, and hypertension, also increase the risk of cardiac morbidity and mortality in pregnancy.
Additional risk factors for peripartum cardiomyopathy have been identified: African race, preeclampsia, and a family history of cardiomyopathy.
15 Studies have suggested that there may be a genetic predisposition to developing peripartum cardiomyopathy. A genetic study of 172 patients with postpartum cardiomyopathy showed mutations in common with dilated cardiomyopathy.
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RISK ASSESSMENT
It is important to have a proper risk assessment for women of childbearing age with known
CVD.
17 Preconception counseling can help inform patients of their risk of pregnancy. In some cases, the individual’s cardiac status requires optimization before pregnancy. Additionally, teratogenic medications have to be exchanged for safer options. For women considering fertility treatments, the risk and benefits of these treatments with regard to cardiac disease can be evaluated during prepregnancy counseling. Women with congenital heart disease and an identified genetic mutation may consider preimplantation genetic screening. In women who choose not to become pregnant, safe contraception is an important consideration.
18Risk assessment includes a detailed history and physical examination, a 12-lead electrocardiogram, and transthoracic echocardiogram. When needed, advanced imaging including cardiac computerized tomography and magnetic resonance imaging can provide valuable additional details. Certain valvular conditions, cardiomyopathies, and complex congenital heart disease might require exercise testing or cardiopulmonary testing to complete risk assessment.
Different risk estimation scores and algorithm have been developed based on large population-based studies. The CARPREG (CARdiac disease in PREGnancy) risk score includes four predictors
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19 (Table 18.1). Women with a score of zero and no lesion-specific risks are considered low risk, whereas women with a risk score of one or more require a comprehensive evaluation. The CARPREG II risk index added more predictors
20 (Table 18.2). ZAHARA (Zwangerschap bij vrouwen met een Aangeboren HARtAfwijking-II) investigators assessed pregnancy-related complications in women with congenital heart disease
21 (Table 18.3) and developed a weighted risk score, which includes eight predictors with each quintile of score assigning a maternal risk of cardiovascular complications during pregnancy ranging from 2.9% to 70%. The most widely used risk classification system, which is recommended by the European Society of Cardiology, is the modified World Health Organization (mWHO) classification
(Table 18.4).
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22 The mWHO classification categorizes patients into four pregnancy
risk classes, class I-IV.
22 When compared with the mWHO classification, both CARPREG and ZAHARA underestimate the cardiac risk for low-risk pregnancies.
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23Women with cardiac disease are also at a higher risk of obstetric complications including miscarriage, preterm delivery, premature rupture of membranes, and postpartum hemorrhage. There is also an increased risk of adverse neonatal outcomes in women with cardiac disease. Cardiomyopathy and pulmonary hypertension portend the highest risk of obstetric and neonatal complications. Based on the risk assessment, the frequency of antenatal visits and the site and mode of delivery are established. In most cases, vaginal delivery is recommended and is the preferred choice, but some exceptions exist. High-risk patients should be managed at expert centers by a multidisciplinary team that includes cardiologists, obstetricians, maternal-fetal medicine specialists, and cardiac anesthesiologists.
