Managing Specific Cardiac Conditions During Pregnancy, Labor, and Delivery

Aortic Dissection

For the expectant mother, there is an increased risk of aortic dissection because of the histologic and hemodynamic changes that occur during pregnancy. Histologic changes in the aortic wall include fragmentation of the reticulum fibers, diminished mucopolysaccharides, and loss of corrugation of the elastic fibers. Hemodynamic changes include increased stroke volume and blood volume.

In patients with Marfan syndrome, who are predisposed to aortic dissection, there is an approximately 1% risk of aortic rupture during pregnancy. As reflected in various guidelines, pregnant women with Marfan syndrome and a dilated aorta (>4.5 cm) are at increased risk of aortic dissection.

Treatment of type A dissection, involving the ascending aorta, is surgical. Treatment of type B dissection, limited to the descending aorta, is medical, with surgery reserved for complications, such as leakage, rupture, or continuing expansion. When surgery is undertaken for type A dissection, two lives must be considered. If the fetus is at less than 28 weeks’ gestation, surgery with the fetus in situ is recommended. If the fetus is viable and over 32 weeks’ gestation, cesarean delivery followed immediately with aortic repair is recommended. If the fetus is between 28 and 32 weeks’ gestation, a decision about the best option must be made.

Aortic Regurgitation

Aortic regurgitation is generally well tolerated during pregnancy. If it is severe or associated with preexisting left ventricular (LV) dysfunction, congestive heart failure may occur and should be treated as systolic left-sided failure is treated in other conditions.

Aortic Stenosis

Mild and moderate degrees of aortic stenosis may be well tolerated during pregnancy, but women with severe aortic stenosis have a significant risk of complications during pregnancy. Patients of concern are those with a valve area less than 1.0 cm ² or a mean gradient over 50 mm Hg. In such patients, the already limited valve orifice cannot accommodate the dramatic blood volume expansion and increased cardiac output of pregnancy. The result is a significant increase in the transvalvular gradient, which may lead to pulmonary edema. The time of greatest risk begins in the second trimester, when increases in cardiac output are greatest, and persists until several days postpartum, when blood volume and cardiac output begin to return to prepregnancy levels. In the immediate postpartum period, relief of vena caval compression and the autotransfusion from the placenta add to the volume overload state. The main risk is that patients will develop left-sided congestive heart failure. Therapy should include diuretics and beta blockers; the latter may be particularly helpful because they slow the heart rate, which is beneficial for patients with aortic stenosis. Digitalis is generally not useful except in the presence of concomitant severe LV systolic failure. A patient with symptomatic severe aortic stenosis without significant aortic regurgitation may be a candidate for an aortic balloon valvuloplasty. This procedure can reduce the degree of stenosis and help the patient get through the pregnancy.

Vasodilators are contraindicated in aortic stenosis. Oxytocin is a vasodilator and must be used cautiously because it may decrease blood pressure significantly. Epidural and spinal anesthesia should be titrated slowly and cautiously because of vasodilation and hypotension, which may worsen valvular gradients.

Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular (RV) cardiomyopathy is a rare inherited type of cardiomyopathy that is caused by genetic mutations coding for the desmosomal proteins. The prevalence is estimated at 1 in 5000. This disorder is estimated to be responsible for 20% of sudden deaths in young people. Inheritance is autosomal dominant. These defects lead to RV dysfunction, fibrofatty infiltration of the right ventricle, and life-threatening arrhythmias usually originating in the right ventricle. Because arrhythmias often develop during exercise-induced catecholamine increases, patients are usually advised to limit exercise. The left ventricle is often involved as well. Generally, implantable cardioverter defibrillators are used in patients who have had ventricular arrhythmias or aborted sudden cardiac death. The number of reported cases of pregnancy in women with this disorder is small, but they seem to do well. Bauce et al. (2006) reported on six women, all of whom did well. Two had vaginal deliveries and four had cesarean sections. The fetuses had no negative consequences.

Atrial Septal Defect

There are three types of atrial septal defects (ASDs): ostium primum, ostium secundum, and sinus venosus. The ostium primum type is usually part of an atrioventricular (AV) canal defect (see later discussion). Ostium secundum defects are in the fossa ovalis, and sinus venosus defects are higher in the atrium near the junction of the superior vena cava.

In the absence of pulmonary hypertension, most patients with ASDs tolerate pregnancy well. There is an increased risk of atrial arrhythmias, such as atrial fibrillation.

Patients with ASDs who do not have pulmonary hypertension have left-to-right shunting of blood through the ASD. The increased blood volume of pregnancy tends to increase the shunt, but the decreased peripheral resistance tends to reduce the shunt, so the net change is usually minimal. Postpartum hemorrhage, with the sudden onset of vasoconstriction, coupled with reduced venous return, may lead to a dramatic increase in the atrial shunt. Patients with a repaired ASD (either surgical or transcatheter device closure) without long-term sequelae are at low risk of cardiac complications during pregnancy.

Atrioventricular Canal Defects

Atrioventricular canal (also called AV septal) defects refer to a spectrum of defects with abnormalities of the AV valves, atrial septum, and ventricular septum. A complete AV canal defect constitutes a primum ASD, an inlet ventricular septal defect (VSD), and a common five-leaflet AV valve. Surgical repair involves closing the septal defects and separating the common AV valve into left and right AV valves. Incomplete or partial AV canal defects typically have a primum ASD with a cleft mitral valve. Despite surgical repair, there may be variable degrees of regurgitation. AV canal defects are associated with Down syndrome. Most patients with Down syndrome are unable to become pregnant. Complete AV canal defects are usually repaired in infancy. If a patient has partial defects, it is possible that they will have escaped detection or be unrepaired at the time of pregnancy.

The hemodynamic effects of these lesions depend on the size of the septal defect and the degree of shunting, as well as the degree of mitral and tricuspid regurgitation. Pulmonary hypertension, if present, dramatically increases the risk of pregnancy.

Patients with residual shunts are at increased risk of endocarditis.

The incidence of congenital heart disease in children of women with AV canal defects may be higher than with other maternal congenital heart conditions.

Coarctation of the Aorta

Most women with a history of coarctation of the aorta have had a surgical repair before they become pregnant. The risk of coarctation during pregnancy depends on the presence of residual obstruction, aneurysm at the coarctation repair site, and associated lesions, such as a bicuspid aortic valve or aortopathy. Noncontrast magnetic resonance imaging should be considered during pregnancy for patients with repaired coarctation who have never had cross-sectional imaging. It will allow for detection of residual arch narrowing, aneurysm at the repair site, and accurate measurement of the thoracic aorta. Patients with a coarctation repaired with Dacron-patch aortoplasty are at particularly high risk of aneurysm formation and aortic rupture during pregnancy. Patients with coarctation may also have berry aneurysms in the brain.

A potential hazard during pregnancy is severe hypertension, which is difficult to treat. Patients with a history of coarctation also have an increased risk of preeclampsia. Patients with coarctation have abnormal aortic walls and are prone to aortic dissection, a risk that increases during pregnancy. Vaginal delivery is preferred, but it is important to limit the second stage of labor in high-risk patients so as to minimize aortic stress. The risk of endocarditis is increased in patients with a bicuspid aortic valve.

Mothers with a history of coarctation have a higher-than-expected (3%) risk of having a baby with congenital heart defects.

Cor Pulmonale and Lung Disease

In general, pregnancy stresses the cardiovascular system more than the respiratory system, and the pulmonary hypertension associated with pulmonary disease presents a greater hazard to the pregnant woman than the lung disease itself.

Coronary Artery Disease

Pregnant women presenting with angina are evaluated in much the same way as nonpregnant women. Generally, stress testing is the first step. If the resting electrocardiogram (ECG) shows normal stress test (ST) segments, a plain ECG treadmill test may suffice. If the ST segments are not normal at rest, then stress echocardiography is appropriate because nuclear studies should not be performed during pregnancy. If results of stress testing are positive, the appropriate course is coronary angiography with angioplasty and stenting, if needed, at the same setting. If possible, angiography should be delayed until after the third trimester. The uterus should be shielded. Because of the hypercoagulable state during pregnancy, drug-eluting stents are preferred. Aspirin and clopidogrel can be used during pregnancy.

For medical treatment of angina, metoprolol is considered safer than atenolol based on a study showing lower birthweights in women treated with atenolol. There is no information on the effects of statin drugs on fetal development, so these drugs probably should not be used.

Pregnancy can be safely undertaken by women who have had a prior coronary artery bypass grafting procedure.

Dilated Cardiomyopathy Preceding Pregnancy

There is virtually no information regarding how to manage patients with preexisting dilated cardiomyopathy as distinct from peripartum cardiomyopathy. It is unknown whether patients with this disorder will undergo worsening of LV function associated with pregnancy, as do many patients with peripartum cardiomyopathy. Management is the same as it would be for patients with LV dysfunction of any etiology. Beta blockers can be continued or initiated. Angiotensin-converting enzyme (ACE) inhibitors should not be used because of the risk of oligohydramnios and renal failure in the fetus. If ACE inhibitors were being given before pregnancy, consider substituting hydralazine and long-acting nitrates instead. Digitalis is safe during pregnancy. Furosemide can be used to help relieve symptoms.

Double-Outlet Right Ventricle

Double-outlet right ventricle describes a heterogeneous group of anomalies with the common feature of both great vessels originating from the morphologic right ventricle. It may be associated with a relatively normal left ventricle connected to the right ventricle by a VSD or a hypoplastic left ventricle. In some cases, there is also transposition of the great arteries (TGA). For pregnant women with double-outlet right ventricle, the prognosis depends on their specific anatomy and what type of surgical repair was performed; it is impossible to make generalizations.

Ebstein’s Anomaly

In Ebstein’s anomaly, the tricuspid valve is displaced toward the cardiac apex. The displacement results in varying degrees of tricuspid regurgitation and enlargement of the right atrium, which will have a ventricularized portion. Ebstein’s anomaly is associated with accessory AV bypass tracts and atrial arrhythmias. The degree of tricuspid regurgitation and RV dysfunction can vary widely, depehnding on the degree of tricuspid displacement. Roughly 50% of patients have an ASD or a patent foramen ovale (PFO). Some patients with right-to-left shunts are cyanotic.

There have been a number of reports on small series of patients with Ebstein’s anomaly undergoing pregnancy. In the largest, 44 women had 111 pregnancies. The live birth rate was 75%. There were seven therapeutic terminations and 19 spontaneous abortions. Most of the spontaneous abortions (13 of 19) occurred in the patients with an ASD or PFO. There were no maternal deaths and two neonatal deaths.

Pregnancy after tricuspid valve repair or replacement is well tolerated. Women with cyanosis considering pregnancy are often candidates for surgical repair and may want to consider this before pregnancy.

Ehlers-Danlos Type IV (Vascular Type)

Ehlers-Danlos syndromes are a group of connective tissue disorders characterized by hypermobile joints. A number of different types have been described. Of concern during pregnancy is the vascular type (type IV), which can be associated with a variety of complications, including uterine rupture. These patients also are susceptible to rupture of the aorta, with a risk estimated at 25% of pregnancies. In patients with vascular-type Ehlers-Danlos syndrome, arterial dissections may be difficult to repair because of tissue fragility. A report of 183 pregnancies in 81 women showed that 12 women died within 2 weeks of delivery. Five died from uterine rupture, and 7 died because of a rupture of a major blood vessel. Pregnancy in these women should be considered high risk. It is not known if cesarean section can improve the outcome. The vascular type of Ehlers-Danlos syndrome is autosomal dominant, so women have a 50% chance of passing it on to their children.

Hypertrophic Cardiomyopathy

Women with hypertrophic cardiomyopathy (HOCM) generally tolerate pregnancy well. Diastolic dysfunction is common. Late in the disease, systolic dysfunction may develop in some patients. Patients usually have some mitral regurgitation. Theoretically, the increased intravascular volume of pregnancy, which leads to ventricular dilation, should be beneficial in reducing the subaortic obstruction. However, this effect is offset by the increase in cardiac output, and subaortic gradients tend to increase as pregnancy progresses. The increased heart rate of pregnancy exacerbates diastolic dysfunction.

Tachycardia caused by the pain and stress of delivery and the blood loss related to delivery may increase the degree of obstruction and increase the risk of pulmonary edema.

Patients with any degree of systolic dysfunction and those with severe gradients appear to be at greater risk during pregnancy. Peak gradients over 30 mm Hg should trigger increased vigilance.

Patients with HOCM are at risk for arrhythmias including ventricular tachycardia and atrial fibrillation. Pregnancy does not seem to worsen arrhythmic burden, but data are limited. Atrial fibrillation is poorly tolerated by patients with HOCM, and if it occurs, early cardioversion should be undertaken.

In patients with HOCM, beta blockers should be continued during pregnancy. Metoprolol is preferred. There are concerns about atenolol causing fetal growth restriction. Verapamil can be used but has been associated with heart block in fetuses.

Vaginal delivery is preferred; cesarean section should be reserved for obstetric indications.

Epidural and spinal anesthesia should be titrated slowly and cautiously because of vasodilation and hypotension, which may worsen subvalvular gradients.

Oxytocin should be used carefully to avoid hypotension, tachycardia, and arrhythmia. Administer only a slow intravenous (IV) infusion.

Blood loss should be replaced, but excessive fluid could put the patient at risk for pulmonary edema.

Inappropriate Sinus Tachycardia

Inappropriate sinus tachycardia is a condition that is relatively common and predominantly seen in young women. It is defined as a syndrome in which the resting daytime heart rate exceeds 100 beats/min and the average 24-hour heart rate is over 90 beats/min. The tachycardia also must produce symptoms and have no identifiable cause. Postural changes in blood pressure must be excluded. Symptoms include palpitations, dizziness, lightheadedness, and near syncope. The etiology is uncertain. Inappropriate sinus tachycardia should be distinguished from both orthostatic hypotension and postural orthostatic tachycardia syndrome (POTS), in which the tachycardia occurs predominantly or only on standing. Often, it is associated with other types of autonomic dysfunction and psychiatric issues.

Beta blockers are the mainstay of therapy; if they fail, ivabradine (a relatively new drug that specifically targets the sinus node) has been successful in a few cases. However, ivabradine is not recommended for use during pregnancy because of findings of embryofetal toxicity in animal studies. Physical training is helpful, but it is often difficult to get patients to exercise as they dislike the associated increase in heart rate. Often, compression garments and drugs, such as fludrocortisone, are used to increase intravascular volume, but these therapies are unproven. Fludrocortisone should not be used in pregnant women because teratogenicity has been demonstrated in animal studies. In refractory cases, catheter or surgical ablation of the sinus node is sometimes undertaken, but ablation can lead to complications, such as the need for a pacemaker; symptoms can recur even in procedures that initially appear successful.

The prevalence of inappropriate sinus tachycardia is uncertain, but one European study found a prevalence of 1% in middle-aged participants. Despite the fact that this is a relatively common condition, reports of cases in pregnant women are very limited, suggesting that the physiologic changes in the cardiovascular system and the fluid retention of pregnancy may have a beneficial effect. The few case reports of pregnant women with inappropriate sinus tachycardia suggest that it is generally benign. At least one case of rate-related cardiomyopathy in pregnancy has been reported.

Kawasaki Disease

Kawasaki disease is a systemic febrile illness of childhood characterized by diffuse vasculitis. There is no definitive test, and the diagnosis is made on clinical grounds. Typical features include abrupt onset of high fever, polymorphous exanthem, pharyngeal erythema, cracked fissured lips, a strawberry tongue, bilateral conjunctival injection, cervical lymphedema, extremity changes (edema, palmar, and sole erythema), and periungual desquamation in the convalescent phase. The most serious manifestation is coronary arteritis, which can lead to the formation of a coronary aneurysm in 20% to 25% of untreated patients. Treatment with aspirin and IV immunoglobulin can reduce this risk to about 5%. About half of the coronary aneurysms in patients with Kawasaki disease will regress. Those that persist may lead to ischemic heart disease, myocardial infarction (MI), and death. The aneurysms virtually never rupture but are prone to thrombosis. Most women will have had their coronary artery disease addressed by the time they are of childbearing age and may not require extensive further evaluation. Persistent aneurysms pose an ongoing risk of thrombosis, and those greater than 8 mm seem to be especially high risk. Because pregnancy is a hypercoagulable state, the concern is that it may trigger aneurysm thrombosis. Although the numbers are small, virtually all reported cases of pregnancy in women with Kawasaki disease have resulted in good outcomes for both the mother and the baby. Treatment with low-dose aspirin (81 mg/day) seems sufficient to prevent aneurysm thrombosis in pregnant women. However, the 2017 Kawasaki disease guidelines recommend that those with medium to large coronary artery aneurysms should be supervised by a multidisciplinary team, including a cardiologist, to aid in thromboprophylaxis management during pregnancy and delivery.

Left Ventricular Noncompaction

Left ventricular noncompaction is a rare cardiomyopathy characterized by deep trabeculations in the LV myocardium. The degree of LV dysfunction is variable. Some individuals present with overt heart failure, fatal arrhythmias, and thromboembolic events; others remain asymptomatic. Echocardiographic criteria to help identify and assess noncompaction rely on the presence of LV myocardial trabeculations and a two-layer distinction between compacted and noncompacted myocardium. One must be careful of making an initial diagnosis in a pregnant woman because an increase in the degree of LV trabeculation in pregnancy has been reported to occur in as many as 25% of women. In 8% of pregnant women, the trabeculations are pronounced enough to meet the criteria for making a diagnosis of LV noncompaction. During a postpartum follow-up period of 24 ± 3 months, 73% of women demonstrated complete resolution of trabeculations, and 5% showed a marked reduction in the trabeculated layer.

If the diagnosis of LV noncompaction is made before pregnancy, the potential risk during pregnancy depends on the degree of LV dysfunction. It is uncertain if the usual medical therapy for LV dysfunction benefits patients with noncompaction. Successful pregnancies in women with noncompaction have been reported. In one case report, the woman had an uncomplicated course, but the baby also had noncompaction and died of heart failure shortly after birth.

Loeys-Dietz Syndrome

Loeys-Dietz is a genetic syndrome with clinical features similar to Marfan syndrome, including an aorta susceptible to aneurysms and dissection, hypertelorism, and a cleft palate. Congenital heart defects, such as ASDs, bicuspid aortic valves, and patent ductus arteriosus (PDA), are sometimes present. The concern during pregnancy is that the aorta might rupture, and patients should be managed accordingly. Hypertension, if present, should be treated aggressively. Beta blockers may be considered, and the second stage of labor should be curtailed.

Marfan Syndrome

Patients with Marfan syndrome are predisposed to aortic dissection. They have an approximately 1% risk of aortic rupture. If aortic dissection occurs, surgery is the treatment of choice for type A dissection. Medical therapy with beta blockers is the treatment of choice for type B dissections.

As reflected in various guidelines, women with Marfan syndrome and a dilated aorta, larger than 4.5 cm, are probably at increased risk and should undergo surgical repair before pregnancy.

Women with Marfan syndrome should be kept on beta blockers throughout pregnancy. Labetalol is probably the agent of choice because it has a history of extensive use in pregnancy. Metoprolol is a reasonable alternative. When given early in pregnancy, atenolol has been associated with fetal growth restriction and thus should be avoided altogether.

Women with Marfan syndrome have an increased risk of spontaneous abortion and premature delivery, likely because of connective tissue abnormalities in the uterus, which occur in some patients with Marfan syndrome.

Cesarean section should be considered to avoid the blood pressure fluctuations associated with vaginal delivery.

Mitral Regurgitation

Mitral regurgitation is generally well tolerated during pregnancy. If it is severe or if it is associated with preexisting LV dysfunction, congestive heart failure may occur and should be treated as systolic left-sided failure is treated in patients with other conditions.

Mitral Stenosis

Mitral stenosis is poorly tolerated during pregnancy. Ideally, it will be detected and treated before pregnancy. Medical treatment can be with beta blockers to prolong diastolic filling time. For younger women with rheumatic mitral stenosis who become pregnant, percutaneous valvuloplasty can be considered.

Patients who do have mitral stenosis and become pregnant typically develop symptoms during the second trimester, when heart rate and cardiac output increase significantly. The usual symptom is dyspnea; occasionally, atrial fibrillation occurs. If the stenosis is severe, pulmonary edema may occur.

The best way to estimate the degree of stenosis is with a valve area. A normal value is 4.0 to 6.0 cm ² . Severe stenosis is indicated by a valve area of 1.5 cm ² or less.

Myocardial Infarction

Myocardial infarction is a rare complication of pregnancy, with an incidence of 1 in 10,000 pregnancies. The most common cause of MI in pregnancy is probably coronary dissection, and although data are virtually nonexistent, the risk of recurrence during subsequent pregnancies is believed to be high. Other causes include coronary atherosclerosis, thrombosis, and cocaine abuse. About 80% of MIs occur in the peripartum period. Older literature suggests that MI during pregnancy most commonly involves the left anterior descending artery.

The diagnosis of MI in pregnant women is made as it is in patients who are not expecting: a clinical history of typical chest pain, ECG changes of ST-segment elevation or Q waves, and elevation of cardiac enzymes. In the postpartum period, creatine kinase isoenzyme MB (CKMB) levels rise because they are released from the myometrium. Troponin levels should not be affected by pregnancy.

Pregnant women with MI should be investigated with coronary angiography. Angioplasty should be undertaken urgently for appropriate cases with thrombotic or embolic etiologies. Dissection in pregnancy usually involves most of the length of the affected coronary artery and therefore must be treated surgically. Delivery is deferred until the interventions for the MI have been completed. The mortality rate is high.

Pericardial Disease

About 40% of women develop a benign hydropericardium by the third trimester, but the development of pericarditis is unusual. When pericardial disease does develop, it may take the form of idiopathic pericarditis, pericarditis associated with connective tissue disease, constrictive pericarditis, or tamponade.

Peripartum Cardiomyopathy

Peripartum cardiomyopathy is defined as the development of systolic heart failure in the last month of pregnancy or within 5 months after delivery without identifiable etiology. Risk factors include maternal age older than 30 years, gestational hypertension, and twin pregnancies.

Treatment is the same as for systolic heart failure of any cause. Beta blockers, such as carvedilol, are the mainstay of therapy for systolic heart failure in nonpregnant patients, and there is no reason to think they should not be effective during pregnancy, but they have not been studied extensively. ACE inhibitors can be used postpartum, but they are contraindicated during pregnancy. Hydralazine and nitrates may be used during pregnancy. Diuretics are used for relief of congestion.

Patients with severe LV dysfunction are at risk for the development of mural thrombi; anticoagulation should be considered. In patients with persistent LV dysfunction, the mortality rate may be as high as 20% with subsequent pregnancies.

In about 50% of patients, normalization of LV function occurs within 6 months of delivery.

Peripheral Edema

Peripheral edema is very common, occurring in up to 80% of normal pregnancies. Typically, it manifests late in the second trimester or in the third trimester; the development of edema earlier than this may indicate a pathologic situation. In general, there is no recommended treatment for peripheral edema during pregnancy. Sodium restriction is ineffective. In the absence of pulmonary edema, diuretics generally should be avoided because of the potential adverse effects on hemodynamics and electrolyte concentrations. For comfort, women should avoid standing for prolonged periods or sitting with the legs dependent; frequent leg movement is appropriate. Lying on the side also may be helpful because it avoids vena cava compression. In cases of severe leg edema, wearing compression stockings or wrapping the legs with elastic wraps can be helpful; reportedly, a figure-8 wrap is more effective than a spiral wrap.

Patent Ductus Arterriosus

The outcome of pregnant patients with a PDA is usually favorable, but clinical deterioration and heart failure have been reported. A large, nonrestrictive PDA would be expected to cause pulmonary hypertension before reaching childbearing age. In these cases, pregnancy is contraindicated. In patients with pulmonary hypertension, reversal of the shunt can occur secondary to hypotension and can be prevented with vasopressors. Patients with a history of a patent ductus that has been ligated or a small hemodynamically insignificant PDA, are expected to do well in pregnancy with a low risk of cardiac complications.

Postural Orthostatic Tachycardia Syndrome

Postural orthostatic tachycardia syndrome is a syndrome in which the heart rate increases with standing but blood pressure does not drop, which distinguishes it from orthostatic hypotension. The diagnosis of POTS is made based on a 30-beats/min increase in heart rate with a change from sitting to standing and with a less-than-20-mm-Hg drop in systolic blood pressure and the development of symptoms.

Treatment includes drugs, such as beta blockers and ivabradine, to slow the heart rate and compression garments and fludrocortisone to increase intravascular volume. Vasoconstrictors, such as ProAmatine, are often used; another common therapy is serotonin reuptake inhibitors.

POTS does not seem to contribute to pregnancy-related complications.

About half of women with POTS report improvement of symptoms with pregnancy. About one-third report worsening of symptoms, and the rest have unchanged symptoms. Postpartum, about half of women report improved or stable symptoms.

Pulmonary Atresia

Pulmonary atresia with a VSD is generally considered an extreme form of tetralogy of Fallot, in which there is congenital atresia of the RV outlet. In pulmonary atresia with VSD, the anatomy and size of the main and branch pulmonary arteries dictate surgical options. In the most severe form, there is an absence of a main pulmonary artery and an absence or severe hypoplasia of the branch pulmonary arteries; the lungs receive their blood flow from collateral arteries extending from the aorta (major aortopulmonary collateral arteries). In such cases, patients rarely survive to adulthood without surgical intervention. There is one report of 14 patients who had 24 pregnancies. Two were unoperated. There were no maternal deaths and one neonatal death. The miscarriage rate was 50%.

Pulmonary atresia with intact ventricular septum is a condition in which, by definition, there is no VSD, and the only outflow from the right atrium is across an ASD. Surgical repair is based on the size of the right ventricle and tricuspid valve. In cases in which the tricuspid valve and right ventricle are markedly hypoplastic, patients undergo surgical palliation as a single ventricle (see later discussion). In patients with an adequate tricuspid valve and right ventricle, their management and pregnancy outcomes are similar to patients with tetralogy of Fallot.

Pulmonary Hypertension

Pulmonary hypertension is defined as a mean pulmonary artery pressure greater than 25 mm Hg as assessed by right heart catheterization. Pulmonary hypertension is classified into five main types based on etiology: (1) pulmonary arterial hypertension, which can be idiopathic or associated with other conditions, such as systemic sclerosis or congenital heart disease; (2) pulmonary hypertension associated with left-heart disease; (3) pulmonary hypertension associated with lung disease; (4) chronic thromboembolic pulmonary hypertension; and (5) an idiopathic group. Surgical procedures are recommended for those with the chronic thromboembolic type; surgery could be considered before pregnancy. It would be best to consider patients with pulmonary hypertension as five distinct groups, but because all these conditions are rare and the number of pregnant patients with them is small, almost all series mix etiologic groups.

Improved medical care for patients with pulmonary hypertension has increased their life expectancy, resulting in more women with pulmonary hypertension considering pregnancy or becoming pregnant. Pulmonary hypertension during pregnancy is a high-risk situation for both the mother and the fetus, and thus, pregnancy in women with pulmonary hypertension should be discouraged. The maternal mortality rate has been reported as high as 56% in patients with severe pulmonary hypertension, although, as for all patients with pulmonary hypertension, the prognosis for pregnant women with the disorder has been improving. More recent studies indicate mortality rates of 17% in patients with idiopathic pulmonary hypertension and 28% in those with congenital heart disease, and most recently, a group from France has reported a 5% maternal mortality rate in a group of women with pulmonary hypertension related to congenital heart disease. The reduced mortality rate may be due, in part, to the apparent lower mortality in women who respond to calcium channel blockers or other therapy. Most cases of death occur in the early postpartum period. Heart failure is most common, but sudden death and thromboembolism also contribute.

During pregnancy, pulmonary resistance decreases in normal women. In patients with pulmonary hypertension, this decrease is limited, leading to a rise in pulmonary pressures, which often leads to right heart failure. Shifting of the intraventricular septum caused by the increased right heart pressures also may impair left heart filling, leading to diastolic left-sided impairment, which compromises cardiac output. Women with Eisenmenger syndrome may have increasing right-to-left shunting, which leads to hypoxemia, and may lead to increased pulmonary vasoconstriction and worsening right heart failure.

A retrospective review of pregnant women with pulmonary hypertension was conducted at four academic tertiary care institutions from 2001-2015 and detailed the use of advanced therapies such as pulmonary vasodilators, extracorporeal membrane oxygenation, inotropes, and vasopressors. Women with primary pulmonary arterial hypertension (type 1) or chronic thromboembolic pulmonary hypertension (type 4) were more likely require advanced therapies and dual therapy than women with other types of pulmonary hypertension. Use of anticoagulation varied by site with incomplete data from all institutions. Intrapartum pulmonary artery catheterization was utilized in nearly 30% of the women in labor, and no adverse events were reported to have occurred following placement or use of the pulmonary artery catheters.1

When mothers have pulmonary hypertension, neonatal survival rates are about 90%. The main risks to the fetus are related to maternal hypoxemia and include preterm delivery, growth restriction, and stillbirth.

If a woman with pulmonary hypertension does become pregnant, she must be monitored carefully, and if signs of decompensation are detected, early therapeutic abortion should be considered. Deterioration of pulmonary hypertension during pregnancy occurs most often between weeks 20 and 24, by which time most of the pregnancy-associated hemodynamic changes have occurred. In women who decompensate during this time period, therapeutic abortion is recommended. A second period of high risk occurs postpartum. If a woman with pulmonary hypertension deteriorates, vasodilator therapy should be started immediately because outcomes are poor in cases in which therapy is delayed.

Many of the drugs used to treat pulmonary hypertension are contraindicated during pregnancy ( Table 7.1 ). Endothelin receptor antagonists are category X. Treatment options for pregnant women with pulmonary hypertension include calcium channel blockers (category C), epoprostenol, iloprost, phosphodiesterase type 5 (PDE5) inhibitors, oxygen, nitric oxide, and others. Combination therapy—often used in nonpregnant patients—also may be necessary in pregnant patients.