Pregnancy and valve disease

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 pregnant patients 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 patients with bicuspid aortic valve, with mitral stenosis, with Marfan syndrome, and with prosthetic heart valves are discussed separately. (See "Bicuspid aortic valve: Preconception and pregnancy care" and "Mitral stenosis: Preconception and pregnancy care" and "Heritable thoracic aortic diseases: Pregnancy and postpartum care" and "Management of antithrombotic therapy for a prosthetic heart valve during pregnancy" and "Anticoagulation during pregnancy and postpartum: Agent selection and dosing".)

PRECONCEPTION OR INITIAL EVALUATION

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

In resource-abundant health care systems, patients are often 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 resource-limited health care systems, for instance in patients with undiagnosed rheumatic mitral stenosis who first present during pregnancy [1].

In general, there are many health outcome benefits to seeking preconception counseling. Patients with valvular heart disease (VHD) should have a preconception evaluation by a cardiologist with expertise in pregnancy and VHD [2]. Risk assessment for patients with VHD should involve a focused evaluation of the risk for the mother and baby. Many patients with heart disease are unaware of the risks of pregnancy, and patient education is an important aspect of the preconception assessment [3]. (See "The prepregnancy 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 (LV) systolic function is generally unchanged during pregnancy, though alterations in Doppler indices of ventricular function during normal pregnancy have been reported [4].

Cardiac magnetic resonance imaging as a risk stratification tool in pregnancy is most useful in patients with VHD who have associated aortopathies (ie, patients with Marfan syndrome or bicuspid valve-associated aortopathy) [5-7] or who have valve lesions in the setting of complex congenital heart disease.

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 patients with congenital heart disease [8]. Exercise testing is useful in patients with severe asymptomatic aortic stenosis to quantify functional capacity and assess blood pressure response to exercise. In patients 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 patients with VHD considering pregnancy has not been determined. Elevated levels of natriuretic peptides are reported during uncomplicated pregnancies of patients with established heart disease, making interpretation more complicated [9,10]. Normal levels of natriuretic peptides are useful in excluding cardiac decompensation in pregnancy [9,10].

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 patients with high-risk valvular heart disease (VHD) may require intervention prior to pregnancy to minimize risks or may be advised to avoid pregnancy [2,11-13]. High-risk lesions include symptomatic or selected asymptomatic mitral stenosis and severe symptomatic aortic stenosis [2,12,13].

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, the Ross procedure, and valve repair [2]. For those patients requiring a valve replacement, the choice of prosthesis should be based on shared decision-making with the patient. Cardiac surgery should be avoided, if possible, during pregnancy. While the maternal risks are similar to those in nonpregnant patients, cardiopulmonary bypass during pregnancy poses significant risk for the fetus [14].

Valve replacement prior to pregnancy raises complex issues and necessitates a detailed discussion on the risks and benefits of various valve options with the patient [15]. 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 and need for reinterventions with bioprosthetic valves.

●Patients 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, patients 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 [16-18], subsequent reports have not confirmed this finding [19-24].

For patients who require aortic valve replacement prior to pregnancy, replacement of the aortic valve by a pulmonary autograft (Ross procedure) by an experienced surgeon is a potential option [2]. However, patients undergoing the Ross procedure face a risk of aortic graft or right ventricular outflow tract reoperation of 15 percent at 25 years [25]. (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 patients, is associated with a risk of fetal defects (warfarin embryopathy and fetopathy) 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 do not cross the placenta and are not teratogenic but are associated with increased risk 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 patients with moderate valvular disease and those who have undergone reparative surgery who are contemplating pregnancy not delay pregnancy. If possible, valve repair, instead of replacement, is preferred 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. (See "Percutaneous mitral balloon commissurotomy in adults".)

●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 is usually recommended 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".)

●In resource abundant countries, aortic stenosis in adolescent children and young adults is almost always due to bicuspid aortic valve, and noncalcified severely stenotic bicuspid valves can sometimes be treated with percutaneous aortic balloon valvotomy rather than aortic valve replacement. (See "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" and "Bicuspid aortic valve: Preconception and pregnancy care", section on 'AS intervention prior to pregnancy'.)

GENERAL APPROACH TO RISK STRATIFICATION — 

Risk assessment should incorporate data on lesion-specific risks, general risk factors relevant for all patients with heart disease, and patient-specific data such as cardiac imaging, exercise test results, or biomarkers.

Risk stratification will determine the frequency of clinical reevaluation during pregnancy and the need for antenatal care at a specialized cardio-obstetric center. Risk assessment and progress during pregnancy will also establish labor and delivery as well as postpartum plans.

Modified WHO classification of maternal cardiovascular risk — The Working Group on Pregnancy and Contraception classified risk associated with pregnancy for patients with heart disease using modified World Health Organization (WHO) classification categories [26]. 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 [12]:

●Modified WHO risk class I – Conditions in this class 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 – 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 patients often have residual pulmonic regurgitation or stenosis.

•Cardiology follow-up at least every trimester is recommended.

●Modified WHO risk class II to III – Conditions in this class 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.

•Follow-up at least every other month at a referral hospital for pregnant patients with cardiovascular disease is recommended.

●Modified WHO risk class III conditions – These 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.

•Follow-up at least every other month or every month at a center with expertise in caring for pregnant patients with cardiovascular disease is recommended.

●Modified WHO risk class IV conditions – These 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.)

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

•If pregnancy continues, follow-up at least monthly at a center with cardiology and obstetric expertise in caring for pregnant patients with cardiovascular disease is recommended.

Maternal cardiac risk prediction scores — There are two frequently used general risk scores: the CARPREG (Cardiac Disease in Pregnancy) risk score and the ZAHARA (Zwangerschap bij vrouwen met een Aangeboren HARtAfwijking-II, translated as Pregnancy in patients with congenital heart disease II) risk score. While neither of the risk scores were derived specifically for patients with valve disease, they can be a helpful starting point for estimating cardiac risks during pregnancy. In addition, a rheumatic valve disease specific risk score is also available.

The CARPREG study was an observational prospective cohort study of 562 consecutive pregnant patients (599 pregnancies) in Canada with acquired or congenital heart disease [27,28]. 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 LV outflow tract gradient >30 mmHg) (1 point).

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

●Poor baseline 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 [28]. (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 [29]. Ten predictors of maternal cardiac complications were identified and incorporated into a weighted risk score with the following risk 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 LV outflow tract obstruction (2 points)

•Systemic ventricular dysfunction (2 points)

•No prior cardiac interventions (1 points)

•Mechanical valves (3 points)

•High-risk aortopathies (2 points)

•Pulmonary hypertension (2 points)

•Coronary artery disease (2 points)

•Late pregnancy assessment (1 points)

The predicted risk for maternal cardiac events in patients 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 patients with exclusively congenital heart disease, including predominantly complicated lesions [30]. 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 HF 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 pulmonic regurgitation as additional independent risk factors for adverse events [31].

A valve disease-specific risk score, the DEVI score, is based on an observational study of 820 pregnancies in patients with rheumatic heart disease in India [1]. A weighted risk score was created based on seven variables, including:

●A history of cardiac events prior to pregnancy (score 4+)

●Moderate mitral stenosis (score 4+)

●Severe mitral stenosis (score 2+)

●Mild mitral stenosis (score 1+)

●Prosthetic valve replacement (score 2+)

●Pulmonary hypertension (score 2+)

●Use of cardiac medications at the first booking visit (score 1-)

A score ≥5 points was associated with high risk of adverse outcomes.

In a validation study that included 577 pregnancies (95 percent of the valve disease was secondary to rheumatic heart disease), the DEVI score showed better agreement between predicted probabilities and observed events compared with the CARPREG-II risk score [32].

Fetal and neonatal risk predictors — In patients 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 [33,34]. 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 [35]:

●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 patients with congenital heart disease: Specific lesions" and "Pregnancy in women with congenital heart disease: General principles", section on 'Inheritance'.)

SPECIFIC VALVE LESION RISKS AND MANAGEMENT — 

In addition to the general risk predictors discussed above, lesion-specific risks should be factored into this assessment [2,12]. Most patients 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.

Specific lesions

Aortic stenosis — The most common cause of aortic stenosis among patients of childbearing age is congenital bicuspid aortic valve disease [36-38]. Aortic stenosis due to rheumatic heart disease is an uncommon cause and is generally accompanied by mitral stenosis, occurring in a minority of pregnant patients with mitral stenosis (eg, 5 percent [1]).

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.

HF and atrial and ventricular arrhythmias are the most common pregnancy complications reported in patients with aortic stenosis and these occur most often in patients with severe aortic stenosis [33,36,37,39,40]. In patients with fixed outflow tract obstruction, the inability to accommodate to the increased cardiac output and stroke volume can increase the LV end diastolic pressure, precipitating pulmonary edema or arrhythmias. Maternal deaths and aortic dissection in patients with bicuspid valve aortopathy are rare.

In a review of publications between 1985 and 2019 on pregnancy outcomes in patients 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 patients with severe aortic stenosis and 8 and 2 percent for patients with moderate aortic stenosis. Maternal mortality for patients with severe aortic stenosis was 2 percent [40].

High rates of obstetric and fetal/neonatal complications have been reported in patients with significant aortic stenosis [36,37,39].

Aortic stenosis is staged according to valve anatomy, stenosis severity, LV 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 patients with severe aortic stenosis require careful preconception assessment; blood pressure response to exercise can be helpful in risk stratification [35].

All patients 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, patients 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 patients with aortic stenosis secondary to bicuspid aortic valve disease are discussed separately. (See "Bicuspid aortic valve: Preconception and pregnancy care".)

Mitral stenosis — In patients 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 [33,41,42].

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

In a review of publications between 1985 and 2019 on pregnancy outcomes in patients 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 patients with severe mitral stenosis and 18 and 5 percent for patients with moderate mitral stenosis [40]. Maternal mortality for patients with severe mitral stenosis was 3 percent, and for patients with moderate mitral stenosis it was 1 percent.

If severe mitral stenosis is recognized before pregnancy, percutaneous mitral balloon valvotomy is recommended if valve morphology is favorable for intervention [43-45].

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 patients with mitral stenosis who have or develop atrial fibrillation should receive anticoagulation, similar to the nonpregnancy recommendations, but with the additional care taken regarding the choice and timing of therapy to minimize maternal and fetal risks [2,35]. (See "Anticoagulation during pregnancy and postpartum: Agent selection and dosing".)

Patients who develop HF despite adequate heart rate control should be treated with diuretics. Rarely, patients 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 patients with mitral stenosis is discussed separately. (See "Mitral stenosis: Preconception and pregnancy care" and "Percutaneous mitral balloon commissurotomy in adults".)

Pulmonic stenosis — Isolated pulmonary valve stenosis is an uncommon congenital heart defect among patients 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 HF, 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 patients with combined repaired and unrepaired valvular pulmonic stenosis [47]:

●There were no maternal cardiac complications (arrhythmia, HF, or other cardiovascular events) in over 100 pregnancies.

●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]. (See "Pulmonic valve stenosis in adults: Management", section on 'Severe stenosis' and "Pregnancy in women with congenital heart disease: General principles", section on 'Individual risk factors'.)

The risk of recurrence of congenital heart disease in offspring of patients 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 is 50 percent.

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

Tricuspid stenosis — Tricuspid stenosis in patients of childbearing age is very rare. 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 patients 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, LV size and systolic function, and symptoms (table 3) [2].

Patients with asymptomatic aortic regurgitation (stage B or C1) and preserved LV systolic function tolerate pregnancy well.

A study of pregnancy outcomes in patients with moderate or severe valve regurgitation reported on 40 pregnancies in patients with aortic regurgitation [56]. Most patients with aortic regurgitation had bicuspid aortic valves. Maternal cardiac events occurred in 5 percent of the pregnancies.

Patients with severe aortic regurgitation with symptoms (stage D), LV systolic dysfunction, severe LV dilation (stage C2), or pulmonary hypertension may develop cardiac complications during pregnancy.

Patients with severe aortic regurgitation with LV systolic dysfunction (LVEF <30 percent) should be advised to avoid pregnancy [35]. If a woman with severe aortic regurgitation and significant LV 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 patients, 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 [14]. (See 'Valve surgery and catheter interventions during pregnancy' below.)

Pregnant patients 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 "Heritable thoracic aortic diseases: Pregnancy and postpartum care".)

Issues related to pregnancy in patients with aortic regurgitation due to a bicuspid aortic valve are discussed separately. (See "Bicuspid aortic valve: Preconception and pregnancy care".)

Mitral regurgitation — Mitral regurgitation in patients of childbearing age may be secondary to mitral valve prolapse, congenital heart disease (atrioventricular canal defects), or rheumatic heart disease. Mild mitral regurgitation is well tolerated during pregnancy. Moderate or severe mitral regurgitation can be tolerated during pregnancy if there is no LV systolic dysfunction or pulmonary hypertension.

In a study examining pregnancy outcomes in patients with valve regurgitation, 145 pregnancies occurred in patients with moderate or severe mitral regurgitation [56]. Mitral regurgitation was most commonly associated with rheumatic heart disease or mitral valve prolapse. Adverse maternal cardiac events occurred in 15 percent of pregnancies overall; however, adverse cardiac event rates were significantly lower in patients who had no cardiac events prior to pregnancy, normal LV systolic function, and no evidence of pulmonary hypertension.

A study of 390 patients with rheumatic mitral valve disease from the Registry of Pregnancy and Cardiac Disease (ROPAC) investigators included 117 patients with isolated mitral regurgitation. HF occurred in 23 percent of the pregnancies in patients with moderate or severe mitral regurgitation [42].

Patients with symptomatic severe mitral regurgitation should have mitral valve repair or replacement prior to pregnancy [2,57]. If feasible, mitral valve repair is preferred to valve replacement. Patients with severe mitral regurgitation and severe LV systolic dysfunction (LVEF <30 percent) or significant pulmonary hypertension should be advised to avoid pregnancy [35]. (See "Surgical procedures for severe chronic mitral regurgitation".)

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

In a study examining pregnancy outcomes in patients with moderate or severe valve regurgitation, 101 pregnancies occurred in patients with moderate or severe pulmonic regurgitation [56]. Most patients with pulmonic regurgitation had congenital heart disease. Adverse maternal cardiac events occurred in 3 percent of the pregnancies.

Right HF risk is increased in patients with moderate to severe pulmonic regurgitation who have at least one additional risk factor [48]:

●Multiple gestation

●Branch pulmonary artery stenosis

●Right ventricular systolic dysfunction

●Right ventricular hypertrophy

Tricuspid regurgitation — Tricuspid regurgitation among patients 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 tricuspid regurgitation is well tolerated during pregnancy. Patients with moderate or severe tricuspid regurgitation can also do well throughout pregnancy if they have no history of cardiac events prior to pregnancy and normal ventricular function. Right-sided HF and atrial arrhythmias have been reported [56].

The risk assessment and management of pregnancy in patients with Ebstein anomaly is discussed separately. (See "Ebstein anomaly: Management and prognosis", section on 'Management of pregnancy'.)

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 nonpregnant 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. In the Canadian study of pregnancy outcomes in patients with valve regurgitation, adverse maternal cardiac events occurred in 27 percent of the 71 pregnancies in patients with moderate or severe multivalve regurgitation [56].

Prosthetic mechanical valves — The management of pregnant patients 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. Patients 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 "Anticoagulation during pregnancy and postpartum: Agent selection and dosing".)

ANTENATAL CARDIOLOGY FOLLOW-UP — 

Patients 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 [60].

Patients 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, patients at low risk are seen by their cardiologist for an early antenatal visit (first trimester) and perhaps in the third trimester at the time of the peak hemodynamic load of pregnancy [35]. Patients with moderate or severe valve lesions are followed more frequently, either every trimester or more frequently. Follow-up should include periodic transthoracic echocardiograms. (See 'Modified WHO classification of maternal cardiovascular risk' above.)

VALVE SURGERY AND CATHETER INTERVENTIONS DURING PREGNANCY — 

In appropriate candidates, surgery or catheter-based interventions prior to pregnancy can decrease pregnancy risk. Successful cardiac surgery or valve interventions can improve fertility, 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 [2,13,61]. When possible, valve surgery or valve interventions during pregnancy should be avoided unless patients have refractory symptoms unresponsive to medical therapy.

Catheter-based valve interventions, including valvuloplasty and percutaneous transcatheter valve implantation, have been used during pregnancy, primarily to treat severely stenotic symptomatic valve lesions. However, catheter-based interventions are associated with risk of ionizing radiation to the fetus and potential maternal and fetal complications; therefore, they are only used when patient symptoms are refractory to medical therapy. Most experience during pregnancy is with percutaneous mitral balloon valvotomy in low- and middle-income countries where rheumatic heart disease is common. Percutaneous mitral balloon valvotomy has been frequently and successfully used to treat severe symptomatic mitral stenosis during pregnancy with good results. In one study of 246 cases of mitral balloon valvuloplasty during pregnancy in Morocco, the procedural complication rate was 1.8 percent, and 95 percent of the cohort reached term after the procedure. Less commonly, percutaneous balloon aortic or pulmonic valvuloplasty have been used to treat severe symptomatic aortic or pulmonary stenosis. Only a very limited number of cases of transcatheter aortic valve implantation have been performed in pregnant patients, and this approach should only be considered in very select cases [61].

The maternal risks of cardiac surgery are approximately the same as those in nonpregnant patients [14,62,63], but cardiopulmonary bypass during pregnancy incurs risk for the fetus related to nonpulsatile blood flow and reduced uteroplacental flow [14,62-65]. 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 [14,63,66-68].

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

●In 21 pregnant patients undergoing cardiothoracic surgery at the Mayo Clinic between 1976 and 2009, there was one early maternal death that occurred during emergency surgery in a woman with an aortic valve prosthesis thrombosis and severe LV dysfunction [14]. Of the 14 patients who delivered after surgery (excluding patients with cesarean delivery immediately prior to surgery), there were three fetal losses, three preterm deliveries, seven term infants, and one patient lost to follow-up.

●Fetal and neonatal mortality has been reported to be between 19 and 33 percent [14,62,63,65].

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 American Heart Association/American College of Cardiology valve guidelines [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, patients can be positioned in the left lateral position 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 when surgery is performed later in gestation (>24 weeks). 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 patients suggest that hypothermia to 25°C does not adversely affect the fetus. However, rewarming may increase both uterine activity and the risk of preterm labor. Although moderate hypothermia (32°C) 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

Location and type of delivery — In general, pregnant patients with low-risk valve lesions can deliver at their local hospital. Patients 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 [35]. In patients 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 patients should be evaluated by the obstetric anesthesia team prior to delivery. Patients with high-risk lesions should receive maternal cardiac monitoring with continuous telemetry during labor and delivery. Intra-arterial blood pressure monitoring may be useful in patients 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 patients with VHD. Some groups advocate for planned cesarean delivery in patients with severe aortic stenosis. (See "Bicuspid aortic valve: Preconception and pregnancy care", section on 'Mode of delivery'.)

Further details regarding the anesthetic and obstetric management of labor and vaginal delivery in patients 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 patients who are breastfeeding [70]. LactMed is a useful resource.

Endocarditis prophylaxis — Routine antimicrobial prophylaxis for infective endocarditis is not recommended for most patients (with or without heart disease) during pregnancy and delivery [2,12,71].

●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: Preincision planning and patient preparation", section on 'Antibiotic prophylaxis and antiseptic preparation'.)

●Vaginal delivery is not an indication for routine antibiotic prophylaxis, as the rate of bacteremia and infection associated with this procedure is low [12,71]. 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) some clinicians administer antibiotic prophylaxis (using the same regimens used to prophylax against endometritis prior to cesarean delivery) prior to vaginal delivery (eg, 30 to 60 minutes before the estimated time of delivery) [72,73]. (See "Cesarean birth: Preincision planning and patient preparation", section on 'Antibiotic prophylaxis and antiseptic preparation'.)

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 patients 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 [74]. Rare case reports have described bacterial endocarditis following vaginal delivery [74,75]. 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 [76].

In patients with established or suspected infection that could cause bacteremia (such as chorioamnionitis or pyelonephritis), the underlying infection should be treated in the usual fashion. (See "Clinical chorioamnionitis" and "Urinary tract infections and asymptomatic bacteriuria in pregnancy", section on 'Acute pyelonephritis' and "Prevention of endocarditis: Antibiotic prophylaxis and other measures", section on 'Timely treatment of infection'.)

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 [35]. 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 patients 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

●Cardiovascular risk in pregnant patients with valvular heart disease – The hemodynamic changes of pregnancy can result in cardiac decompensation in some patients with valvular heart disease (VHD) lesions. (See 'Introduction' above.)

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

●Extremely high-risk lesions – Patients with severe mitral stenosis, symptomatic severe aortic stenosis, or other VHD associated with severe left ventricular systolic dysfunction (left ventricular ejection fraction [LVEF] <30 percent) and/or significant pulmonary hypertension should be advised to avoid pregnancy due to the extremely high risk of maternal and fetal complications. (See 'Modified WHO classification of maternal cardiovascular risk' above and 'Mitral stenosis' above and 'Aortic stenosis' above.)

●Risk during pregnancy with mild valve disease – Most patients with mild forms of VHD will do well throughout pregnancy. (See 'Specific valve lesion risks and management' above.)

●Risk associated with mitral stenosis – Pregnant patients with mitral stenosis, even if mild, are at risk for pregnancy-related complications. (See 'Mitral stenosis' above and "Mitral stenosis: Preconception and pregnancy care".)

●Risk associated with a mechanical heart valve – Patients with mechanical heart valves are at high risk for pregnancy-related complications, including valve thrombosis. (See 'Prosthetic mechanical valves' above.)

●Antenatal follow-up – For a pregnant patients with valve disease, the minimum frequency of antenatal follow-up is based upon the estimated level maternal and fetal risk. Patients 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.)

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

ACKNOWLEDGMENT — 

The UpToDate editorial staff acknowledges Jacob A Udell, MD, MPH, FRCPC, who contributed to earlier versions of this topic review.