INTRODUCTION — Hemodynamic changes during pregnancy, including increases in heart rate, stroke volume, and cardiac output (see "Maternal adaptations to pregnancy: Cardiovascular and hemodynamic changes"), can result in cardiac decompensation in women with valvular heart disease (VHD). Stenotic valve lesions are generally less well tolerated during pregnancy compared with regurgitant lesions. The risk of complications varies according to the type and severity of the underlying VHD.

This topic will discuss risk assessment and management of native valve disease during pregnancy. Evaluation and management of pregnant women with bicuspid aortic valve, with mitral stenosis, with Marfan syndrome, and with prosthetic heart valves are discussed separately. (See "Bicuspid aortic valve: Management during pregnancy" and "Pregnancy in women with mitral stenosis" and "Pregnancy and Marfan syndrome" and "Management of antithrombotic therapy for a prosthetic heart valve during pregnancy" and "Use of anticoagulants during pregnancy and postpartum".)

PRECONCEPTION OR INITIAL EVALUATION

Timing — When possible, women should undergo preconception assessment and counseling so that they are able to make informed pregnancy decisions. For women who have not had preconception counseling, a complete risk evaluation should occur at the first antenatal visit.

In developed health care systems, women are typically aware of significant health conditions in advance of pregnancy; however, occasionally, pregnancy unmasks a previously unrecognized valve lesion. This latter scenario may be more frequent in developing health care systems, for instance in women with undiagnosed rheumatic mitral stenosis who first present during pregnancy.

In general, there are many health outcome benefits to seeking preconception counseling. Women with valvular heart disease (VHD) should have a preconception evaluation by a cardiologist with expertise in pregnancy and VHD. Risk assessment for women with VHD should involve a focused evaluation of the risk for the mother and baby. Many women with heart disease are unaware of the risks of pregnancy, and patient education is an important aspect of the preconception assessment [1]. (See "The preconception office visit".)

Preconception evaluation — Preconception (or initial if the patient presents during pregnancy) evaluation should include a detailed history, information on prior valve interventions (valvuloplasty, valvotomy, and surgical repairs/replacements), symptom status, a complete physical exam, a 12 lead electrocardiogram, a transthoracic echocardiogram, and an assessment of functional status. In patients presenting with valve disease, it is important to determine a cause such as a history of rheumatic fever or rheumatic heart disease, prior chest irradiation, systemic illness that can induce valvulitis, or a family history of VHD, congenital heart disease, aortopathy, or premature sudden cardiac death. (See "Clinical manifestations and diagnosis of rheumatic heart disease" and "Non-coronary cardiac manifestations of systemic lupus erythematosus in adults".)

Echocardiographic assessment — A transthoracic echocardiogram is indicated in patients with known or suspected valve disease, preferably prior to conception [2]. The echocardiogram is important to determine the type and severity of valvular lesions, the degree of left or right ventricular dilation and/or dysfunction, and the presence of pulmonary hypertension or any other associated cardiac defects. In the setting of stenotic valve lesions, valve gradients may increase during pregnancy and should be interpreted accordingly. The severity of regurgitation may remain unchanged, increase, or decrease during pregnancy. Left ventricular systolic function is generally grossly preserved during pregnancy, though alterations in Doppler indices of ventricular function during normal pregnancy have been reported [3].

Cardiac magnetic resonance imaging as a risk stratification tool in pregnancy is most useful in women with VHD who have associated aortopathies (ie, women with Marfan syndrome and aortic coarctation) [4-6].

Exercise testing — Exercise testing (with or without echocardiograms) or cardiopulmonary testing may aid risk assessment and can objectively estimate functional capacity, which is an important determinant of pregnancy outcome. An abnormal (blunted) chronotropic response to exercise has been associated with adverse outcomes in pregnancy in women with congenital heart disease [7]. Exercise testing is useful in women with severe asymptomatic aortic stenosis to quantify functional capacity and assess blood pressure response to exercise. In women with mitral stenosis who have symptoms out of proportion to the degree of valve stenosis, stress echocardiography can be helpful to examine changes in the right ventricular systolic pressure with exercise.

Biomarkers — The utility of cardiac biomarkers for risk stratification in women with VHD considering pregnancy is not described. Elevated levels of natriuretic peptides are reported during uncomplicated pregnancies of women with established heart disease, making interpretation difficult [8,9]. Normal levels of natriuretic peptides may be useful in excluding cardiac decompensation in pregnancy [8,9]. Median brain natriuretic peptide (BNP) levels during normal pregnancy are approximately twofold those in nonpregnant controls [10], while median BNP levels in a series of pregnant women with heart disease were over twofold those in pregnant women without heart disease [8].

Medications — Review of current medication use and dose will inform a discussion between the practitioner and patient on the benefits and risks of medication use in pregnancy. Some cardiac medications (eg, angiotensin-converting-enzyme inhibitors and angiotensin II receptor blockers) will need to be discontinued or substituted with an alternative drug if they are teratogenic or pose a risk for the developing fetus.

INTERVENTIONS PRIOR TO PREGNANCY — Some women with high-risk valvular heart disease (VHD) may require intervention prior to pregnancy to minimize risks or may be advised to avoid pregnancy [11]. High-risk lesions include severe symptomatic or asymptomatic mitral stenosis and severe symptomatic aortic stenosis.

Patients referred for valve intervention prior to possible pregnancy should receive prepregnancy counseling by a cardiologist with expertise in managing patients with VHD during pregnancy. This review should include a discussion of the risks and benefits of all options for transcatheter or surgical intervention, including mechanical prosthesis, bioprosthesis, and valve repair [2]. Cardiac surgery should be avoided, if possible, during pregnancy. The maternal risks are approximately the same as those in nonpregnant women, but cardiopulmonary bypass during pregnancy poses significant risk for the fetus [12].

The decision is much more complex when a valve replacement is required and necessitates a detailed discussion on the risk and benefits of various valve options with the patient [13]. In brief, the trade-off involves the risk of pregnancy-related thromboembolic complications and the fetal risks of anticoagulant therapy (warfarin is teratogenic) with mechanical valves versus the limited durability of bioprosthetic valves.

●Women with normal-functioning bioprosthetic heart valves who do not require anticoagulation generally tolerate pregnancy well. However, approximately 30 to 35 percent of heterograft prostheses and 10 to 20 percent of homograft prostheses fail within 10 to 15 years of implantation. Thus, women of childbearing age who have a bioprosthesis are likely to require at least one additional valve surgery during their lifetime. Although some early studies suggested that valve deterioration is accelerated during or shortly after pregnancy [14-16], subsequent reports have not confirmed this finding [17-22].

For patients who require valve replacement prior to pregnancy, replacement of the aortic valve by a pulmonary autograft (Ross procedure) by an experienced surgeon is a potential option [23]. However, patients undergoing the Ross procedure face a risk of reoperation of 20 percent or more at 15 to 20 years. (See "Choice of prosthetic heart valve for surgical aortic or mitral valve replacement", section on 'Ross procedure'.)

●The risk of pregnancy is high for both the mother and fetus when a mechanical valve is present, largely due to risk of valve thrombosis and thromboembolism and the need for anticoagulation to prevent these complications. All anticoagulants are associated with increased risk of miscarriage (table 1). Warfarin, which is the most reliable anticoagulant for prevention of thromboembolic complications in pregnant women, is associated with a risk of fetal defects (warfarin embryopathy) as well as increased risk of fetal loss compared with low molecular weight heparin. On the other hand, unfractionated heparin and low molecular weight heparin are associated with an increased incidence of mechanical valve thrombosis and thromboembolism. Another potential complication includes bleeding secondary to anticoagulation. These issues are discussed in detail separately. (See "Management of antithrombotic therapy for a prosthetic heart valve during pregnancy".)

Because of these risks, it is preferable that women with moderate valvular disease and those who have undergone reparative surgery who are contemplating pregnancy not delay pregnancy. If possible, prosthetic valve replacement should be avoided when valve intervention is required prior to pregnancy.

The alternative approaches for valve intervention prior to pregnancy vary with the valve lesion:

●Balloon valvotomy is preferred to valve replacement for patients with mitral stenosis with appropriate valvular anatomy; however, open commissurotomy is required if valve morphology is not favorable or the patient has left atrial thrombus or associated moderate or more mitral regurgitation. (See "Percutaneous mitral balloon valvotomy for mitral stenosis".)

●Valve repair is the preferred surgical procedure in patients with mitral regurgitation with indications for valve surgery. If valve replacement is necessary, a bioprosthetic valve should be used when possible because long-term anticoagulation is not required (in the absence of atrial fibrillation). However, degeneration of bioprosthetic valves occurs after 10 to 15 years (depending upon the valve location); as a result, bioprosthetic valve replacement will be needed. (See "Surgical procedures for severe chronic mitral regurgitation".)

●Aortic stenosis in young women is, in developed countries, almost always due to bicuspid aortic valve. Women with noncalcified valves can sometimes be treated with percutaneous aortic balloon valvotomy rather than aortic valve replacement. (See "Bicuspid aortic valve: Management during pregnancy", section on 'Aortic stenosis treatment prior to pregnancy' and "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Balloon valvotomy' and "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults".)

GENERAL APPROACH TO RISK STRATIFICATION — Risk assessment should incorporate general risk factors relevant for all women with heart disease, lesion specific risks when they are available, and patient-specific data such as exercise test results. Risk stratification will determine the frequency of clinical re-evaluation during pregnancy. Risk assessment and progress during pregnancy will also establish labor and delivery as well as postpartum plans.

Maternal cardiac risk predictors — There are two frequently used risk indices: the CARPREG (Cardiac Disease in Pregnancy) and the ZAHARA (Zwangerschap bij vrouwen met een Aangeboren HARtAfwijking-II, translated as Pregnancy in women with congenital heart disease II) scoring systems.

The CARPREG study was an observational prospective cohort study of 562 consecutive pregnant women (599 pregnancies) with acquired or congenital heart disease [24,25]. Four predictors of an adverse maternal cardiac event in pregnancy were identified:

●Left heart obstruction (mitral valve area <2 cm², aortic valve area <1.5 cm², or peak left ventricular outflow tract gradient >30 mmHg) (1 point)

●History of a prior cardiac event (heart failure, transient ischemic attack, or stroke) or arrhythmia (1 point)

●Poor baseline New York Heart Association (NYHA) functional class (class 3 or 4) or cyanosis (1 point)

●Systemic ventricular systolic function <40 percent (1 point)

A point is allocated for each risk factor identified, and the risk is then estimated on the basis of the total score. Pregnancies with 0, 1, and >1 points had adverse cardiac event rates of 5, 27, and 62 percent, respectively [25]. (See "Acquired heart disease and pregnancy", section on 'Assessing risk' and "Pregnancy in women with congenital heart disease: General principles", section on 'Maternal cardiovascular risk assessment'.)

The CARPREG II study was an extension of the CARPREG study and included 1938 pregnancies from two large tertiary care centers [26]. Ten predictors of maternal cardiac complications were identified and incorporated into a weighted risk score with the following risk predictors:

●Five general predictors

•Cardiac events or arrhythmias prior to pregnancy (3 points)

•Baseline functional class (class 3 or 4) or cyanosis (3 points)

•High-risk valve disease and left ventricular outflow tract obstruction (2 points)

•Systemic ventricular dysfunction (2 points)

•No prior cardiac interventions (1 points)

●Four lesion-specific predictors

•Mechanical valves (3 points)

•High-risk aortopathies (2 points)

•Pulmonary hypertension (2 points)

•Coronary artery disease (2 points)

●One delivery of care predictor

•Late pregnancy assessment (1 points)

The predicted risk for maternal cardiac events in women with a point score of 0 to 1 points was 5 percent, 2 points was 10 percent, 3 points was 15 percent, 4 points was 22 percent, and >4 points was 41 percent.

The ZAHARA score is based upon a retrospective observational cohort study of 1302 completed pregnancies in 714 women with exclusively congenital heart disease, including predominantly complicated lesions [27]. The ZAHARA risk score is derived from a weighted scoring system to predict adverse maternal cardiac events and includes the following factors:

●Mechanical heart valve (4.25 points)

●Severe left heart obstruction (mean pressure gradient >50 mmHg or aortic valve area <1.0 cm²) (2.50 points)

●History of arrhythmias (1.50 points)

●History of cardiac medication use before pregnancy (1.50 points)

●History of cyanotic heart disease (uncorrected or corrected) (1.00 points)

●Moderate-to-severe pulmonary or systemic atrioventricular valve regurgitation (0.75)

●Symptomatic heart failure before pregnancy (NYHA class ≥II) (0.75 points)

The score is divided into five categories of risk based on accrued points: 0 to 0.5 points, 2.9 percent; 0.51 to 1.50 points, 7.5 percent; 1.51 to 2.50, 17.5 percent; 2.51 to 3.50, 43.1 percent; and >3.51, 70.0 percent risk, respectively.

A retrospective single-center study identified the presence of right ventricular systolic dysfunction and/or severe pulmonary regurgitation as additional independent risk factors for adverse events [28].

Fetal and neonatal risk predictors — In women with heart disease, including those with valvular heart disease, fetal and neonatal complications have been reported to occur in as many as 25 percent of the pregnancies [29,30]. Fetal and neonatal complications include preterm delivery, intrauterine growth restriction, reduced birth weight, respiratory distress syndrome, intraventricular hemorrhage, and death. Maternal predictors of fetal and neonatal complications include [31]:

●Left heart obstruction

●Mechanical heart valves

●Poor baseline NYHA functional class (class 3 or 4) or cyanosis

●Use of anticoagulation during pregnancy

●Smoking during pregnancy

●Multiple gestation

●Extremes of age (<20 and >35 years)

The heritability of congenital heart disease should be discussed. Offspring of affected parents are at increased risk of congenital heart disease. The risk of recurrent congenital heart disease (with a lesion same as or different from the parents) varies depending upon the specific defect and genetic predisposition. (See "Pregnancy in women with congenital heart disease: Specific lesions" and "Pregnancy in women with congenital heart disease: General principles", section on 'Inheritance'.)

LESION SPECIFIC RISKS AND MANAGEMENT — In addition to the general risk predictors discussed above, lesion-specific risks should be factored into this assessment [23,31]. Most women with mild forms of valvular heart disease (VHD) will do well throughout pregnancy. Stenotic valve lesions are generally less well tolerated during pregnancy compared with regurgitant lesions but either can lead to decompensation.

Modified WHO classification — The Working Group on Pregnancy and Contraception classified pregnancy risk in women with heart disease using modified World Health Organization (WHO) classification categories [32]. The modified WHO classification of pregnancy risk for VHD and some conditions associated with valve disease are specified in the 2018 European Society of Cardiology guidelines for management of cardiovascular disease during pregnancy [33]:

●Modified WHO risk class I conditions are associated with no detectable increased risk of maternal mortality and no/mild increase in morbidity.

•Valve conditions in this category include mild pulmonic stenosis and mitral valve prolapse. Cardiology follow-up during pregnancy may be limited to one or two visits.

●Modified WHO risk class II conditions are associated with small increased risk of maternal mortality or moderate increase in morbidity.

•Valve conditions in risk class II include repaired tetralogy of Fallot. These women often have residual pulmonary regurgitation or stenosis. Follow-up every trimester is recommended.

●Modified WHO risk class II to III conditions are associated with significantly increased risk of maternal mortality or moderate to severe increased risk of morbidity.

•Valve conditions in risk class II to III include native or tissue VHD not considered WHO I or IV and bicuspid aortic valve with ascending aorta diameter <45 mm.

●Modified WHO risk class III conditions are associated with significantly increased risk of maternal mortality or severe morbidity. Expert counseling is required and this may include consideration of alternatives to pregnancy. Intensive specialist cardiac and obstetric monitoring are needed throughout pregnancy, childbirth, and the puerperium. Monthly or bimonthly cardiology and obstetric follow-up during pregnancy are recommended at a minimum.

•Valve conditions in this category include a mechanical valve, moderate mitral stenosis, severe asymptomatic aortic stenosis, and bicuspid aortic valve with ascending aortic diameter of 45 to 50 mm.

●Modified WHO risk class IV conditions are associated with extremely high risk of maternal mortality or severe morbidity; pregnancy is contraindicated. If a woman presents with a lesion in this class early in pregnancy, termination should be discussed. If pregnancy is terminated, appropriate intervention for high-risk valve and/or aortic disease should be performed before another attempt at pregnancy (see 'Interventions prior to pregnancy' above). If pregnancy continues, care as for class III with monthly or bimonthly cardiology and obstetric follow-up at a minimum.

•Conditions in this category include severe mitral stenosis, severe symptomatic aortic stenosis, bicuspid aortic valve with ascending aorta diameter >50 mm, severe systemic ventricular systolic dysfunction (left ventricular ejection fraction [LVEF] <30 percent, New York Heart Association [NYHA] III to IV), and pulmonary arterial hypertension.

Specific lesions

Aortic stenosis — The most common cause of aortic stenosis among women of childbearing age is congenital bicuspid aortic valve disease [34-36]. Aortic stenosis due to rheumatic heart disease is an uncommon cause and is generally accompanied by mitral stenosis. Pregnancy is usually well tolerated in patients with mild and moderate aortic stenosis, but patients with severe aortic stenosis tolerate the hemodynamic alterations of pregnancy poorly.

Heart failure and atrial and ventricular arrhythmias are the common pregnancy complications reported in women with aortic stenosis and these occur most often in women with severe aortic stenosis [29,34,35,37,38]. In women with fixed outflow tract obstruction, the inability to accommodate to the increased cardiac output and stroke volume can increase the left ventricular end diastolic pressure, precipitating pulmonary edema or arrhythmias. Maternal deaths and aortic dissection are rare [37]. In a review of publications between 1985 and 2019 on pregnancy outcomes in women with aortic stenosis in medium or higher Human Development Index countries, rates of pulmonary edema and new or recurrent arrhythmias were 9 and 4 percent for women with severe aortic stenosis and 8 and 2 percent for women with moderate aortic stenosis. Maternal mortality for women with severe aortic stenosis was 2 percent [38]. High rates of obstetric and fetal/neonatal complications have been reported [34,35,37].

Aortic stenosis is staged according to valve anatomy, stenosis severity, left ventricular geometry and function, and symptoms (table 2) [2]. Patients with aortic stenosis should receive preconception counseling by a cardiologist experienced in managing VHD during pregnancy. Asymptomatic women with severe aortic stenosis require careful preconception assessment; blood pressure response to exercise can be helpful in risk stratification [31].

All women with symptomatic aortic stenosis should have a valve intervention prior to pregnancy.

If symptoms develop during pregnancy, restricted activities are a reasonable first step. Pulmonary edema should be treated with diuretics. Rarely, women with persistent symptoms despite medical therapy may need to be considered for a valve intervention (either valvuloplasty or aortic valve replacement) during pregnancy.

Risk assessment and management of pregnancy in women with aortic stenosis secondary to bicuspid aortic valve disease are discussed separately. (See "Bicuspid aortic valve: Management during pregnancy".)

Mitral stenosis — The most common cause of mitral stenosis among women of childbearing age is rheumatic heart disease. Congenital heart disease (eg, parachute mitral valve) is a less common cause of mitral stenosis.

In women with moderate to severe mitral stenosis, the increased cardiac output and heart rate (decreased diastolic filling time) associated with pregnancy can result in increases in left atrial pressure leading to complications, including atrial fibrillation and pulmonary edema [29,39,40]. In a review of publications between 1985 and 2019 on pregnancy outcomes in women with mitral stenosis in medium or higher Human Development Index countries, rates of pulmonary edema and new or recurrent arrhythmias were 37 and 16 percent for women with severe mitral stenosis and 18 and 5 percent for women with moderate aortic stenosis. Maternal mortality for women with severe mitral stenosis was 3 percent, and for women with moderate mitral stenosis it was 1 percent [38]. As a result, if severe mitral stenosis is recognized before pregnancy, percutaneous mitral balloon valvotomy is recommended if valve morphology is favorable for intervention [41-43].

Beta blockers are the mainstay of therapy for pregnant patients with mitral stenosis; they act by controlling heart rate and increasing the diastolic filling time. Pregnant women with mitral stenosis who have or develop atrial fibrillation should receive anticoagulation, similar to the non-pregnancy recommendations, but with the additional care taken regarding the choice and timing of therapy to minimize maternal and fetal risks [23,31,44,45] (see "Use of anticoagulants during pregnancy and postpartum"). Women who develop heart failure despite adequate heart rate control should be treated with diuretics. Rarely, women with persistent symptoms despite medical therapy may need to be considered for a valve intervention (either valvuloplasty or mitral valve replacement) during pregnancy.

Risk assessment and management of pregnancy in women with mitral stenosis is discussed separately. (See "Pregnancy in women with mitral stenosis" and "Percutaneous mitral balloon valvotomy for mitral stenosis".)

Pulmonic stenosis — Isolated pulmonary valve stenosis is an uncommon congenital heart defect among women of childbearing age. Isolated pulmonary valve stenosis, even if moderate to severe, in the absence of right ventricular dysfunction is usually well tolerated during pregnancy [46]. In very rare instances, severe pulmonic stenosis may result in symptomatic right heart failure, particularly if there is concomitant right ventricular systolic dysfunction.

A literature review found the following rates of complications during completed (>20 weeks gestation) pregnancies among women with combined repaired and unrepaired valvular pulmonic stenosis [47]:

●With respect to the mother, there were no cardiac complications (arrhythmia, heart failure, or other cardiovascular events) in over 100 pregnancies.

●With respect to the fetus or neonate, premature delivery occurred in 16 of 110 pregnancies (14.5 percent), fetal mortality in 1 of 123 pregnancies (0.8 percent), perinatal mortality in 5 of 123 pregnancies (4.1 percent), and recurrent congenital heart disease (of any type) in offspring in 3 of 104 pregnancies (2.8 percent).

When surgical repair or balloon dilatation of congenital pulmonic valve stenosis leaves behind little or no obstruction and a competent valve, the mother can anticipate a normal pregnancy.

The outcomes are not as favorable when pulmonic stenosis is associated with other complex congenital heart lesions [48]. As a rule, women with cyanotic congenital heart disease tolerate pregnancy less well than those with acyanotic heart disease, and cyanosis has a negative impact on fetal outcome. (See "Natural history and treatment of pulmonic stenosis in adults", section on 'Severe stenosis' and "Pregnancy in women with congenital heart disease: General principles", section on 'Individual risk factors' and "Pregnancy in women with congenital heart disease: General principles", section on 'Cyanosis'.)

The risk of recurrence of congenital heart disease in offspring of women with pulmonary stenosis is estimated as 3 to 6 percent. In patients with pulmonary stenosis due to autosomal dominant genetic mutations such as Noonan syndrome, the risk of the recurrence of the syndrome approaches 50 percent.

Percutaneous balloon valvotomy performed during pregnancy in women with symptomatic severe pulmonic stenosis can reduce pregnancy risk [49].

Tricuspid stenosis — Causes of tricuspid stenosis include rheumatic heart disease, congenital atresia or stenosis, right atrial tumors, carcinoid syndrome, or pacemaker lead-related fibrosis. Most cases of tricuspid rheumatic disease present with tricuspid regurgitation or a combination of regurgitation and stenosis [50,51]. Rheumatic tricuspid stenosis almost never occurs as an isolated lesion, but is generally associated with mitral valve disease and, in some cases, the aortic valve [52,53]. (See "Tricuspid stenosis", section on 'Etiology'.)

Symptoms of tricuspid stenosis may first occur during pregnancy, when the cardiac output increases.

There is little experience with balloon valvotomy for tricuspid stenosis during pregnancy, but it appears to be effective in patients with refractory systemic venous congestion. Isolated balloon tricuspid valvotomy and concurrent balloon valvotomy of mitral and tricuspid valves have been successfully performed during pregnancy [54,55]. Great care must be taken to limit radiation exposure.

Aortic regurgitation — In women of childbearing age, aortic regurgitation is often secondary to congenital bicuspid aortic valve disease. Less commonly, it is due to a valve damaged by endocarditis, rheumatic heart disease, or is seen in the setting of an aortopathy.

Chronic aortic regurgitation is staged according to valve anatomy, regurgitation severity, left ventricular size and systolic function, and symptoms (table 3) [2]. Asymptomatic mild to moderate aortic regurgitation (stage B) is usually well tolerated during pregnancy. Women with asymptomatic severe aortic regurgitation and preserved left ventricular systolic function or mild to moderate left ventricular dilation (stage C1) tolerate pregnancy well [25,27]. However, women with severe aortic regurgitation with associated symptoms (stage D), left ventricular systolic dysfunction, severe left ventricular dilation (stage C2), or pulmonary hypertension may develop heart failure during pregnancy due to the volume load.

Women with severe aortic regurgitation with left ventricular systolic dysfunction (LVEF <30 percent) should be advised to avoid pregnancy [31].

If a woman with severe aortic regurgitation and significant left ventricular systolic dysfunction presents early in pregnancy, we suggest termination of pregnancy followed by corrective surgery before another attempt at pregnancy. If the mother declines termination, we manage the patient medically and, as recommended by the American College of Cardiology/American Heart Association guidelines, operate only for refractory NYHA class III or IV symptoms (table 4) [2].

Symptomatic patients can be treated with diuretics and, if necessary, vasodilators (eg, nifedipine). Angiotensin converting enzyme inhibitors and angiotensin II receptor blockers should not be used during pregnancy because of potential harm to the fetus. (See "Management of heart failure during pregnancy" and "Adverse effects of angiotensin converting enzyme inhibitors and receptor blockers in pregnancy" and "Natural history and management of chronic aortic regurgitation in adults", section on 'General management'.)

Cardiac surgery should be avoided during pregnancy if possible. The maternal risks are similar to those in nonpregnant women, but cardiopulmonary bypass during pregnancy poses risks for the fetus. It is preferable to delay surgery, if possible, until the fetus is viable; a cesarean delivery can then be performed as part of a combined procedure [12]. (See 'Cardiac surgery during pregnancy' below.)

Pregnant women with aortic regurgitation due to Marfan syndrome are at risk for aortic dissection; the highest risk is in those with aortic root dilatation. The prophylactic use of beta blockers may minimize aortic dilation during pregnancy in such patients, as discussed separately. (See "Pregnancy and Marfan syndrome".)

Issues related to pregnancy in women with aortic regurgitation due to a bicuspid aortic valve are discussed separately. (See "Bicuspid aortic valve: Management during pregnancy".)

Mitral regurgitation — Mitral regurgitation in women of childbearing age may be secondary to mitral valve prolapse, congenital heart disease (atrioventricular canal defects), or rheumatic heart disease. Mild or moderate mitral regurgitation is well tolerated during pregnancy. Severe mitral regurgitation can be tolerated during pregnancy if there is no left ventricular systolic dysfunction or pulmonary hypertension [25,27].

Women with symptomatic severe mitral regurgitation should have mitral valve repair or replacement prior to pregnancy [56,57]. If feasible, mitral valve repair is preferred to valve replacement. Women with severe mitral regurgitation and severe left ventricular systolic dysfunction (LVEF <30 percent) or significant pulmonary hypertension should be advised to avoid pregnancy [31]. (See "Surgical procedures for severe chronic mitral regurgitation".)

Pulmonic regurgitation — The most common cause of pulmonic regurgitation among women of childbearing age is related to congenital heart disease such as repaired tetralogy of Fallot or post-valvuloplasty in women with pulmonary stenosis. Severe pulmonary regurgitation may be associated with right ventricular dilatation and/or systolic dysfunction. Right-sided heart failure and atrial or ventricular tachyarrhythmias can occur during pregnancy [48,58,59].

Right heart failure risk is increased in women with moderate to severe pulmonary regurgitation who have at least one additional risk factor [48]:

●Multiple gestation

●Branch pulmonary artery stenosis

●Right ventricular systolic dysfunction

●Right ventricular hypertrophy

The management of pregnancy in women with tetralogy of Fallot is discussed separately. (See "Management and outcome of tetralogy of Fallot", section on 'Pregnancy'.)

Tricuspid regurgitation — Tricuspid regurgitation among women of childbearing age may be related to congenital heart disease (eg, Ebstein anomaly, atrioventricular canal defects), secondary to annular dilation in the setting of right ventricular volume overload lesions, or from valve damage (eg, prior infectious endocarditis). Mild and moderate tricuspid regurgitation are well tolerated during pregnancy. In general, women with severe tricuspid regurgitation can also do well throughout pregnancy, but are at higher risk for right-sided heart failure and atrial arrhythmias [60].

The risk assessment and management of pregnancy in women with Ebstein’s anomaly is discussed separately.

Mixed valve lesions — Risk stratification for mixed and multivalve disease is compromised by lack of data. Expert consensus in pregnancy mirrors that for management of the non-pregnant patient with mixed and multivalve disease. The most hemodynamically significant valve lesion will generally be the predominant influence determining risk and care for patients during pregnancy [23].

Prosthetic mechanical valves — The management of pregnant women with prosthetic mechanical valves is complicated due to the increased risk of prosthetic valve thrombosis and thromboembolism related to the relative hypercoagulable state and difficulty managing anticoagulation during pregnancy. Women with older mechanical valves (ball-and-cage valves, single tilting disc), mechanical valves in the mitral valve position, multiple mechanical valves, arrhythmias, and those with a history of thromboembolic events are at higher risk of valve thrombosis than others. This topic is discussed in detail separately. (See "Management of antithrombotic therapy for a prosthetic heart valve during pregnancy" and "Use of anticoagulants during pregnancy and postpartum".)

ANTENATAL CARDIOLOGY FOLLOW-UP — Women with low-risk valvular heart disease (VHD) can often be managed by their local general cardiology and obstetric team. Reassurance is important to prevent anxiety and overtesting [61].

Women with moderate- or high-risk VHD should be followed at a center with cardiologists, high-risk obstetricians (maternal fetal medicine specialists), and obstetric anesthesiologists with experience in VHD and pregnancy.

The frequency of follow-up visits during pregnancy is dependent on the type and severity of the VHD. Typically, women at low risk are seen by their cardiologist for an early antenatal visit (first trimester), at the time of the peak hemodynamic load of pregnancy (third trimester), and postpartum [31]. Women with moderate or severe valve lesions are followed more frequently. Follow-up should include periodic transthoracic echocardiograms. (See 'Modified WHO classification' above.)

CARDIAC SURGERY DURING PREGNANCY — In appropriate candidates, surgery prior to pregnancy can decrease pregnancy risk. Successful cardiac surgery can improve fertility and decrease the fetal risks in women with cyanotic heart disease, enable the mother to better tolerate the physiologic changes of pregnancy, and potentially provide long-term benefits to the subsequent health of mother and child [12].

When possible, cardiac surgery during pregnancy should be avoided [62-65]. The maternal risks are approximately the same as those in nonpregnant women [62,63], but cardiopulmonary bypass during pregnancy incurs risk for the fetus related to nonpulsatile blood flow and reduced uteroplacental flow [62-65]. If cardiopulmonary bypass is needed, high blood flow (2.5 L/min per m²) and mean arterial blood pressure greater than 70 mmHg are recommended to maximize placental perfusion. Rewarming after deep hypothermia can result in preterm labor and delivery [63,66-68].

The following maternal and fetal outcomes were observed after surgery involving cardiopulmonary bypass during pregnancy:

●Among 59 women in one report, three died (5 percent) but none of the deaths were directly related to elective surgery (one due to endocarditis and two due to emergency surgery for an aortic dissection) [62]. A lower mortality rate (3 percent) was noted in another review; this rate was similar to that in nonpregnant women [63].

●Fetal/neonatal mortality in these two reports was 29 and 19 percent, respectively [62,63].

If a woman presents early in pregnancy with a severe valve disease requiring surgery, we recommend considering termination of pregnancy followed by appropriate intervention before another attempt at pregnancy. (See "Pregnancy in women with congenital heart disease: General principles", section on 'Pregnancy termination' and "Pregnancy in women with congenital heart disease: General principles", section on 'Modified WHO classification'.)

If the mother declines termination, we manage the patient medically and operate only for severe, intractable symptoms as recommended by the 2014 American Heart Association/American College of Cardiology valve guideline [2]. If surgery can be safely delayed until the fetus is viable, a cesarean delivery can then be performed as part of a combined procedure.

During surgery, foam wedges may need to be placed under the mother's right side to displace the uterus and minimize aorto-caval compression depending on the stage of the gravid uterus. The fetal heart rate should be monitored continuously. Fetal bradycardia often responds to an increase in pump flow rate. Prolonged fetal bradycardia (less than 80 beats per minute) that is unresponsive to increased pump flow rates is an indication for cesarean delivery if the fetus is at a viable gestational age. (See "Anesthesia for nonobstetric surgery during pregnancy".)

Animal studies and case reports in pregnant women suggest that hypothermia to 25ºC does not adversely affect the fetus. However, rewarming may increase both uterine activity and the risk of preterm labor. Although moderate hypothermia (32ºC) is probably safe, the effects on the fetus have not been well studied.

Cesarean delivery has been successfully performed while the mother was on cardiopulmonary bypass [69].

LABOR AND DELIVERY MANAGEMENT — In general, women with low-risk lesions can deliver at their local hospital. Women with moderate- or high-risk valvular heart disease (VHD), including those with prosthetic valves, should deliver at a center with expertise in pregnancy and heart disease [31]. In women with high-risk lesions, a labor and delivery plan should be prepared in advance and circulated to all members of the health care team. All women should be evaluated by the obstetric anesthesia team prior to delivery. Women with high-risk lesions should have maternal cardiac monitoring with continuous telemetry during labor and delivery. Intra-arterial blood pressure monitoring may be useful in women with severe aortic stenosis or other high-risk valve lesions.

We suggest vaginal delivery with appropriate analgesia/anesthesia and minimization of Valsalva (ie, a "cardiac" delivery) in women with VHD. Some groups advocate for planned cesarean delivery in women with severe aortic stenosis. (See "Bicuspid aortic valve: Management during pregnancy", section on 'Mode of delivery'.)

Further details regarding the anesthetic and obstetric management of labor and vaginal delivery in women with high-risk cardiac disease are discussed separately. (See "Anesthesia for labor and delivery in high-risk heart disease: General considerations" and "Anesthesia for labor and delivery in high-risk heart disease: Specific lesions".)

Medication safety during lactation should be reviewed prior to hospital discharge for women who are breastfeeding [70]. LactMed is a useful resource.

Endocarditis prophylaxis — Routine antimicrobial prophylaxis for infective endocarditis is not recommended for most women (with or without heart disease) during pregnancy and delivery [23,33,71,72].

●Antibiotic prophylaxis to reduce the risk of postpartum endometritis is routinely given prior to all cesarean deliveries (table 5), and will provide protection against endocarditis as well. (See "Cesarean birth: Preoperative planning and patient preparation", section on 'Antibiotic prophylaxis'.)

●Vaginal delivery is not an indication for routine antibiotic prophylaxis, as the rate of bacteremia and infection associated with this procedure is low [33,72]. However, for selected patients deemed at highest risk for adverse outcomes from endocarditis (eg, those with prosthetic heart valves, prior infective endocarditis, or unrepaired cyanotic congenital heart disease), it is reasonable to administer antibiotic prophylaxis prior to delivery (eg, 30 to 60 minutes before the estimated time of vaginal delivery) [73,74]. (See "Antimicrobial prophylaxis for the prevention of bacterial endocarditis", section on 'Patients at highest risk' and "Management of normal labor and delivery", section on 'Infection prophylaxis'.)

Infective endocarditis is a rare and potentially life-threatening complication of pregnancy, although rates have not been well defined. In a study of 299 blood cultures obtained from 83 women without signs of infection at 0 to 30 minutes after vaginal delivery, three patients (3.6 percent) had a single positive blood culture, and all were likely due to specimen contamination [75]. Rare case reports have described bacterial endocarditis following vaginal delivery [75,76]. In a 2014 review of the literature, 90 cases of infective endocarditis in pregnancy or postpartum were identified. The most common risk factors associated with infective endocarditis were intravenous drug use (14 percent), congenital heart disease (12 percent), and rheumatic heart disease (12 percent). Maternal mortality was 11 percent. However, most of the data came from individual case reports and are subject to publication bias [77].

In patients with established infection that could cause bacteremia (such as chorioamnionitis or pyelonephritis), the underlying infection should be treated in the usual fashion. (See "Intraamniotic infection (clinical chorioamnionitis)" and "Urinary tract infections and asymptomatic bacteriuria in pregnancy", section on 'Acute pyelonephritis'.)

POSTPARTUM MANAGEMENT — The frequency of postpartum monitoring will be dictated by the type and severity of the valve lesions and symptom status. The hemodynamic changes of pregnancy may not return to normal for as long as six months following delivery [31]. During this period, especially early postpartum, there is a continued risk of developing cardiac and obstetric complications. In view of the ongoing risks, we suggest monitoring women early (6 to 10 weeks) and late after delivery (up to four to six months). These visits also provide an opportunity to adjust medications to prepregnancy dose scheduling if compatible with lactation [70].

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: Cardiac valve disease" and "Society guideline links: Congenital heart disease in adults" and "Society guideline links: Management of cardiovascular diseases during pregnancy".)

SUMMARY AND RECOMMENDATIONS

●The hemodynamic changes of pregnancy can result in cardiac decompensation in women with severe valvular heart disease (VHD) lesions. (See 'Introduction' above.)

●When possible, women with VHD should have a preconception risk assessment and counseling. For women who have not had preconception counseling, a complete risk evaluation should occur at the first antenatal visit. (See 'Preconception or initial evaluation' above.)

●Most women with mild forms of VHD will do well throughout pregnancy. (See 'Lesion specific risks and management' above.)

●Women with mitral stenosis, even mild mitral stenosis, are at risk for pregnancy-related complications. (See 'Mitral stenosis' above and "Pregnancy in women with mitral stenosis".)

●Women with mechanical heart valves are at high risk for pregnancy-related complications. (See 'Prosthetic mechanical valves' above.)

●Women with severe mitral stenosis, symptomatic severe aortic stenosis, and VHD associated with severe left ventricular systolic dysfunction or significant pulmonary hypertension should be advised to avoid pregnancy due to the high risk of cardiovascular and fetal complications. (See 'Modified WHO classification' above and 'Aortic stenosis' above and 'Mitral stenosis' above.)

●Women with moderate- or high-risk VHD should be referred to a center with experience in pregnancy and heart disease. (See 'Antenatal cardiology follow-up' above and 'Specific lesions' above.)

●In general, vaginal delivery with appropriate analgesia/anesthesia and minimization of Valsalva (ie, a "cardiac" delivery) is preferred in women with VHD. (See 'Labor and delivery management' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff would like to thank Jacob A Udell, MD, MPH, FRCPC, for his past contributions as an author to prior versions of this topic review.