Bicuspid aortic valve: Preconception and pregnancy care

INTRODUCTION — 

Bicuspid aortic valve is the most prevalent congenital cardiac abnormality, affecting 1 percent of the population with a 2 to 3:1 male predominance [1]. A bicuspid aortic valve may be functionally normal, or it may be stenotic and/or regurgitant. Bicuspid aortic valve is the most common cause of congenital aortic stenosis (AS) and the most common cause of isolated aortic regurgitation (AR). Dilation of the ascending aorta is likely to coexist independent of valvular function [2,3]. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults" and "Clinical manifestations and diagnosis of chronic aortic regurgitation in adults".)

Management for patients with bicuspid aortic valve prior to and during pregnancy and delivery will be reviewed here. Issues related to management of bicuspid AS and AR and general principles of congenital heart disease in pregnancy are discussed separately. (See "Bicuspid aortic valve: General management in adults" and "Natural history and management of chronic aortic regurgitation in adults" and "Pregnancy in women with congenital heart disease: General principles".)

PREGNANCY-RELATED RISKS IN PATIENTS WITH BAV

Risk of aortic complications — Pregnant patients with bicuspid aortic valve and aortic dilation are at potential risk of spontaneous aortic dissection, usually in the third trimester or postpartum, especially if there is an associated aortic coarctation [4]. The predisposition to ascending aortic dissection among patients with bicuspid aortic valve reflects an inherent abnormality of the ascending aortic media [4,5]. The development of aortic root and/or ascending aorta enlargement is independent of whether the bicuspid aortic valve is functionally normal, stenotic, or regurgitant. Pregnancy-associated increases in heart rate, blood pressure, and stroke volume result in increased aortic stress, which may promote aortic dilation and/or dissection. It has not been established whether pregnancy also exacerbates intrinsic aortic structural changes. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults" and "Maternal adaptations to pregnancy: Cardiovascular and hemodynamic changes".)

Among patients with bicuspid aortic valve, aortic dilation is common, but the risk of aortic dissection is generally low with contemporary management.

●Frequency of aortic dilation – In a multicenter, international registry of patients with bicuspid aortic valves, 23.3 percent of 568 females (mean age 46.6) had some form of aortopathy (dilation of the aortic root only, ascending aorta only, or diffuse) [6]. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Diseases of the aorta'.)

●Frequency of aortic complications – Among patients with bicuspid aortic valve, aortic complications have been rarely reported [7,8]. As examples:

•A retrospective study of 88 individuals with bicuspid aortic valve identified no dissection or progressive aortic enlargement during pregnancy [9].

•A study identified 29 females (mean age 32) with aortic dissection during pregnancy or within 12 weeks postpartum, representing 0.3 percent of 9707 patients in the International Registry of Acute Aortic Dissection (February 1, 1998 to February 28, 2018) [10]. Among 105 females younger than 35 years old at the time of aortic dissection, 20 (19 percent) had aortic dissection related to pregnancy. The onset of pregnancy-related dissection in 27 females was 4 in the first trimester, 11 in the third trimester, and 12 postpartum (mean of 12.5 days postpartum). Only 2 of the 29 females had bicuspid aortic valve; both had an ascending (type A) aortic dissection during the third trimester, and, in each, a bicuspid aortic valve was first diagnosed after presentation with dissection. Aortic dimensions at the time of dissection were reported for one of these patients: 5.2 cm at the sinus of Valsalva and 4.6 cm at the tubular ascending aorta.

Pre- or postpartum ascending aortic dissection is associated with significant fetal and maternal risk, which has declined with contemporary management. A review of 61 females with pre- or postpartum aortic dissection, including four with bicuspid aortic valve and prepartum ascending aortic dissection, found that aortic root enlargement >4.0 cm and/or an increase in aortic root size during pregnancy were risk factors for type A dissection [11]. Maternal mortality rates ranged from 25 to 30 percent from 1983 to 1994 and declined to 0 percent from 1995 to 2002. Fetal mortality rates ranged from 38 to 50 percent from 1983 to 1994 and declined to 10 percent from 2000 to 2002. (See "Clinical features and diagnosis of acute aortic dissection" and "Management of acute type B aortic dissection".)

It is unknown whether pregnancy changes the natural history of bicuspid-related aortic disease, as has been shown in a study of females with Marfan syndrome [12]. In that study, although the pregnancies were uncomplicated, the prevalence of aortic dissection and elective aortic surgery was higher in females after pregnancy than in a nonpregnant matched cohort. Pregnancy was associated with an increased aortic growth rate, which did not return to baseline after pregnancy. In contrast, an observational study found no impact of pregnancy on the long-term risk of aortic surgery or dissection for both the Marfan and the bicuspid aortic valve patients [7]. As significant advances are made in studying the genetics of this condition, it may be possible to identify those individuals with a bicuspid valve who are at the highest risk of aortic pathology [13].

Risk associated with aortic stenosis — AS in females of childbearing age is primarily due to a congenital bicuspid aortic valve. A unicuspid valve is much less common and is likely to be stenotic in early life. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Genetics'.)

The increased cardiac output of pregnancy adds volume overload to an already pressure-loaded left ventricle (LV) [14]. Mild to moderate bicuspid AS (table 1) is well tolerated during pregnancy because LV systolic function is generally preserved and the LV ejection fraction (LVEF) is usually above normal [15]. (See "Maternal adaptations to pregnancy: Cardiovascular and hemodynamic changes".)

Data quantifying maternal and fetal risk during pregnancy in females with high-risk features are limited. A systematic review of studies published between 1985 and 2019 reported the following rates of complications during pregnancy in females with AS (most with bicuspid aortic valve) [16]:

●Severe AS – For 103 pregnant patients with severe AS, the risk of mortality was 2 percent, of pulmonary edema was 9 percent, and of new/recurrent arrhythmias was 4 percent. The rate of stillbirths was 2 percent, of neonatal death was 3 percent, and of preterm birth was 14 percent.

●Moderate AS – For 81 pregnant patients with moderate AS, no maternal or neonatal deaths were reported. However, the rate of pulmonary edema was 8 percent, of new/recurrent arrhythmias was 2 percent, and of preterm birth was 13 percent.

There are data suggesting that pregnancy in patients with congenital AS has an adverse effect on subsequent cardiovascular risk [17].

Risk associated with aortic regurgitation — Although data are scant, moderate or severe chronic bicuspid aortic regurgitation (AR) is generally well tolerated during pregnancy if LV function and functional reserve are preserved [18]. The more rapid heart rate of pregnancy shortens diastole. This change, coupled with the gestational fall in systemic vascular resistance, reduces regurgitant flow. (See "Pregnancy and valve disease", section on 'Aortic regurgitation'.)

In a series that included 40 pregnancies in patients with AR, heart failure occurred in 1 patient (3 percent), arrhythmias occurred in 1 patient (3 percent), and cardiac death occurred in 1 patient (3 percent) [19].

Heritability — Bicuspid aortic valve occurs sporadically and as an autosomal dominant inherited disorder with variable penetrance. It may occur as an isolated lesion or associated with other congenital or genetic cardiovascular defects or aortopathy syndromes such as Turner syndrome or heritable thoracic aortic diseases such as Loeys-Dietz syndrome. Large family studies have found the prevalence of bicuspid aortic valve to be approximately 9 to 10 percent in first-degree relatives of the individual with bicuspid aortic valve [20,21]. The prevalence of fetal congenital heart disease was 5 in 121 pregnancies (4.1 percent) among patients with congenital AS in a literature review of studies published between 1985 and 2006 [22]. (See "Heritable thoracic aortic diseases: Preconception risk assessment and management", section on 'Prenatal genetic testing' and "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Genetics'.)

ROLE OF PREGNANCY HEART TEAM — 

Since individuals with bicuspid aortic valve are at risk for complications during and following pregnancy, they should receive specialized evaluation, counseling, and management by a multidisciplinary pregnancy heart team prior to conception and during and following pregnancy, including delivery and the postpartum period [23]. The pregnancy heart team should include, at a minimum, a cardiologist, maternal-fetal medicine specialist/obstetrician, cardiovascular surgeon, anesthesiologist, and provider with expertise in genetics (genetic counselor or geneticist) [23-26].

GENERAL PRECONCEPTION CARE

Timing — Preconception care for individuals with bicuspid aortic valve who are contemplating pregnancy includes assessment of maternal and fetal risk and counseling by a multidisciplinary pregnancy heart team. If a pregnant patient with bicuspid aortic valve has not received preconception evaluation and counseling, an assessment of risk and counseling should be provided by the pregnancy heart team as soon as the patient presents for care. (See 'Role of pregnancy heart team' above and "The prepregnancy office visit".)

Detection — A bicuspid aortic valve is typically detected by echocardiography performed to evaluate the murmur of AS and/or aortic regurgitation (AR) or an ejection click. An isolated, functionally normal bicuspid aortic valve is likely to go unrecognized in patients of childbearing age because auscultatory signs are inconspicuous or unrecognized [27]. Rarely, a bicuspid aortic valve is first identified during pregnancy or postpartum after a patient presents with dissection of the thoracic aorta [4,10]. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults" and 'Pregnancy-related risks in patients with BAV' above.)

Evaluation

General evaluation — All patients with bicuspid aortic valve should undergo preconception history, physical examination, and transthoracic echocardiography to confirm the diagnosis and assess aortic valve dysfunction (AS and AR), ascending aortic (aortic root and tubular ascending aorta) size, and any concurrent aortic coarctation [24,28]. Evaluation should also include cross-sectional imaging (eg, computed tomography or magnetic resonance imaging) to detect aortic coarctation and assessment for features of Turner syndrome. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults" and "Bicuspid aortic valve: General management in adults", section on 'Surveillance' and "Clinical manifestations and diagnosis of coarctation of the aorta" and "Turner syndrome: Clinical manifestations and diagnosis".)

Additional tests for asymptomatic severe AS — For patients with severe AS who are asymptomatic, we recommend the following testing to stratify risk [26,28]:

●Exercise testing – Exercise testing is performed to objectively assess functional status and to assess for provocable symptoms. Cardiopulmonary exercise testing is preferred in patients with reduced exercise tolerance [26]. The test is deemed abnormal if exercise provokes symptoms (angina, syncope, or severe dyspnea at low-level exercise), fall in systolic blood pressure >20 mmHg, or complex arrhythmias, or if the maximal achieved workload is limited (<5 metabolic equivalents [METs]).

●B-type natriuretic peptide (BNP) – Elevated plasma BNP level is a complementary test for identifying asymptomatic patients with severe AS at increased risk for decompensation, particularly if the level is >3 times above the upper limit of the age- and sex-adjusted range for healthy adults [29].

For patients with uncertain hemodynamic status after the above noninvasive testing, invasive hemodynamic testing may be helpful.

Genetics evaluation — For patients with bicuspid aortic valve and familial aortopathy (aortic root or ascending aorta dilation) or phenotypic features of Loeys-Dietz syndrome, a genetics evaluation, testing, and counseling should be included in preconception care. Of note, most patients with bicuspid aortic valve and thoracic aortic aneurysms, even if familial, do not have a pathologic genetic variant identified on genetic testing [24]. (See "Heritable thoracic aortic diseases: Preconception risk assessment and management", section on 'Prenatal genetic testing' and "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Genetics'.)

Counseling — Females of childbearing potential with a bicuspid aortic valve should be counseled prior to pregnancy regarding potential maternal and fetal risks and their management, including the role of preconception surgery if indicated. Potential risks that should be discussed include risks of aortic enlargement and aortic dissection, complications of AS and/or AR, endocarditis, and heritability of bicuspid aortic valve. (See 'Pregnancy-related risks in patients with BAV' above and "The prepregnancy office visit".)

Preconception counseling should include discussion of avoidance of exposures (such as alcohol consumption and smoking) and medications that pose risks during pregnancy. Angiotensin converting enzyme inhibitors and angiotensin II receptor blockers are contraindicated during pregnancy. (See "Treatment of hypertension in pregnant and postpartum patients" and "Adverse effects of angiotensin-converting enzyme inhibitors and receptor blockers in pregnancy".)

PRECONCEPTION INTERVENTION

Role of preconception intervention — Intervention for AS, aortic regurgitation (AR), or aortic dilation prior to pregnancy is aimed at reducing the risk of maternal and fetal complications during and following pregnancy, including the risk of requiring surgery during pregnancy. For patients with an indication for valve or aortic surgery, preconception (or postpartum) surgery is preferred to surgery during pregnancy because cardiovascular surgery during pregnancy is associated with fetal and neonatal mortality. (See "Pregnancy and valve disease", section on 'Valve surgery and catheter interventions during pregnancy'.)

Aortic intervention prior to pregnancy — For patients with bicuspid aortic valve, recommendations for prophylactic surgical aortic repair/replacement are based on maximal aortic size and other risk factors [23,24,30]. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'For the ascending aorta'.)

The rationale for preconception aortic intervention is to reduce the risk of progressive aortic dilation and aortic dissection during pregnancy, although data on this risk are limited. (See 'Risk of aortic complications' above.)

The following indications apply to patients with bicuspid aortic valve without Turner syndrome and should be reviewed prior to conception to determine whether preconception aortic surgery is indicated (algorithm 1) (see "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Approach to identifying candidates for aortic surgery'):

●For individuals with bicuspid aortic valve and aortic diameter ≥5.0 cm who are contemplating pregnancy, we suggest preconception surgical aorta repair/replacement [23,24,30]. However, the optimum ascending aorta diameter threshold for aortic surgery prior to pregnancy has not been established, and some experts suggest aortic surgery at an aortic diameter threshold of ≥4.5 cm.

●If cardiac surgery is required for another condition (such as aortic valve replacement for aortic valve disease), concomitant aortic repair is indicated if the aortic diameter is ≥4.5 cm [30].

For patients with Turner syndrome (including those with mosaic karyotypes), specific recommendations for prophylactic aortic surgery apply based upon aortic size adjusted for body size. Management of pregnancy in patients with Turner syndrome is discussed separately. (See "Management of Turner syndrome in adults", section on 'Aortic dilatation' and "Management of Turner syndrome in adults", section on 'Management of fertility and pregnancy'.)

AS intervention prior to pregnancy

●Indications – Patients with AS with a standard indication for valve intervention (such as symptomatic severe AS regardless of LVEF or asymptomatic severe AS with LVEF <50 percent) should delay conception until the AS has been addressed. (See "High-gradient aortic stenosis in adults: Indications for valve replacement".)

In addition, for asymptomatic patients with severe AS with preserved LVEF who are candidates for percutaneous balloon (or surgical) aortic valvotomy, we suggest aortic valvotomy prior to conception. This recommendation is based upon concern for hemodynamic deterioration during pregnancy and delivery. (See 'Risk associated with aortic stenosis' above.)

However, observation during pregnancy is a reasonable alternative for patients with severe AS with preserved LVEF and confirmed absence of symptoms (with normal exercise test and plasma B-type natriuretic peptide level) [23,26,28].

●Choice of intervention – For adults with bicuspid aortic valve with severe AS undergoing valve intervention prior to conception, percutaneous balloon aortic valvotomy (PBAV) or surgical aortic valvotomy is preferred, if feasible [26]. However percutaneous balloon (or surgical) aortic valvotomy is an option only for selected patients (generally <25 years old) with noncalcified severely stenotic aortic valves and no more than mild AR [31]. In patients with a repaired bicuspid aortic valve, the risks associated with pregnancy are lowest when the mean valve gradient is ≤25 mmHg and LV function is normal. The most common complication of PBAV is AR, which is usually mild or moderate [26]. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Procedures for aortic stenosis'.)

Most adults with bicuspid aortic valve with severe AS undergoing valve intervention require aortic valve replacement; for young adults, surgical aortic valve replacement (SAVR) is generally preferred, as the long-term durability and effects of transcatheter bioprosthetic aortic valve implantation (TAVI) are not yet known. Procedures for aortic valve replacement in patients with bicuspid aortic valve including Ross procedure (pulmonary autograft replacement of the aortic valve-and-root plus implantation of a homograft valve-and-root in the pulmonic position) and mechanical valve and bioprosthetic valve replacement are discussed separately. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Procedures for aortic stenosis'.)

AR intervention prior to pregnancy — Patients with severe AR with an indication for aortic valve surgery (including presence of symptoms, marked LV enlargement, or LVEF <50 percent) should undergo aortic valve surgery before pregnancy. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Indications for intervention for AR' and "Natural history and management of chronic aortic regurgitation in adults".)

Options for aortic valve surgery in patients with severe AR include surgical aortic valve replacement and, for selected patients with aortic cusp prolapse, surgical aortic valve repair. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Procedures for aortic regurgitation'.)

On the other hand, asymptomatic patients with moderate or severe AR with normal LV function without indications for valve replacement should not undergo prophylactic valve surgery before pregnancy [32,33]. Data are limited, but clinical observations and hemodynamic considerations suggest that such patients do well during pregnancy, so the risk associated with valve replacement is not warranted. (See "Natural history and management of chronic aortic regurgitation in adults".)

Choice of procedure

Valve and/or aortic procedures — Options for intervention depend upon whether the patient with bicuspid aortic valve requires aortic valve intervention only, repair of the aorta only, or combined aortic valve and ascending aorta surgery. These procedure types are discussed separately. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Rationale for intervention'.)

Choice of valve procedures — Most patients with bicuspid aortic valve with an indication for valve intervention require valve replacement. Alternatives to aortic valve replacement are available for only selected patients with severe bicuspid AS or AR, as discussed below. For AS, only selected patients are candidates for balloon or surgical aortic valvotomy. For AR, only selected patients are candidates for aortic valve repair. (See 'AS intervention prior to pregnancy' above and 'AR intervention prior to pregnancy' above.)

●For severe AS – Aortic valve replacement for severe AS is performed by SAVR or TAVI, although data on TAVI are more limited in patients with bicuspid aortic valve than in patients with tricuspid valve. (See 'AS intervention prior to pregnancy' above and "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Transcatheter aortic valve implantation' and "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Procedures for aortic stenosis'.)

●For severe AR – Aortic valve replacement for severe AR associated with bicuspid aortic valve is generally performed by SAVR. (See 'AR intervention prior to pregnancy' above and "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Procedures for aortic regurgitation'.)

The choices for SAVR are a bioprosthetic valve, a homograft valve, a pulmonary autograft (Ross procedure), and a mechanical valve [33,34]. TAVI involves implantation of a bioprosthetic valve.

The long-term utility of implantation of a bioprosthetic aortic valve in patients of childbearing age is not well established (table 2). Although anticoagulation is generally not required for bioprosthetic valves (after the first three to six months), there is a high rate of structural failure, which may exceed 60 percent at 15 years in younger patients. The failure rate may not be as high for newer-generation bioprosthetic valves. (See "Choice of prosthetic heart valve for surgical aortic or mitral valve replacement".)

Another option that avoids a need for anticoagulation is a Ross procedure that replaces the aortic valve with the patient's own pulmonary valve (pulmonary autograft) and replaces the pulmonary valve with a homograft. The advantage of this procedure is that anticoagulation, with its attendant risks (including fetal risks during pregnancy from vitamin K antagonist [VKA]), is not required. However, cardiovascular complications are common after the Ross procedure, and reoperation/reintervention is often required involving one or both valves. (See "Anticoagulation during pregnancy and postpartum: Agent selection and dosing" and "Choice of prosthetic heart valve for surgical aortic or mitral valve replacement", section on 'Ross procedure'.)

Limited data are available on outcomes during and following pregnancy in patients who have undergone the Ross procedure. In a study of eight patients who had 14 pregnancies after Ross procedure, there were no maternal deaths, no thromboembolic or hemorrhagic events, and no evidence of deterioration of valve function [34]. A later study included 33 patients who had undergone Ross procedure: 11 patients with 18 subsequent pregnancies carried to a gestational age >20 weeks and 22 without subsequent pregnancies [35]. There was no significant change in autograft diameter after the first pregnancy (mean 3.5 cm prior to 3.7 cm after), but the autograft was significantly dilated after the second (mean 4.3 cm) and third (mean 4.5 cm) pregnancies. However, freedom from combined endpoints (reinterventions, autograft dilation ≥5.0 cm, greater than moderate aortic/autograft regurgitation, and death) was higher in the pregnancy group than in the nonpregnancy group. A study of 19 pregnancies in 12 women with a Ross procedure showed that pregnancy was well tolerated, although there was significant neoaortic dilation after pregnancy [36].

The least satisfactory option for valve replacement in anticipation of pregnancy is a mechanical prosthesis, which is generally durable but requires lifelong anticoagulation. VKA (eg, warfarin) is considered the safest form of anticoagulation for the mother with a mechanical heart valve. However, warfarin crosses the placenta, and the fetus is anticoagulated. Warfarin therapy is associated with a dose-dependent risk of embryopathy (particularly during the first trimester), and later in gestation it increases the risk of fetal bleeding and fetal loss. Heparin does not cross the placenta, and low molecular weight heparin use requires anti-Xa dose adjustment during pregnancy for patients with mechanical valve prostheses and is associated with low fetal risk but higher risk of maternal thromboembolism and mortality than VKA. Management of antithrombotic therapy for a mechanical valve during pregnancy is discussed separately. (See "Management of antithrombotic therapy for a prosthetic heart valve during pregnancy".)

ANTEPARTUM CARE

Management of aortic disease

Aortic surveillance during pregnancy — Every pregnant patient with a dilated ascending aorta should undergo echocardiographic measurement of ascending aortic dimensions serially (eg, monthly or every two months if the ascending aorta diameter is ≥4.0 cm; every 12 weeks if the ascending aorta diameter is above normal but <4.0 cm) until the patient is six months postpartum to assess for possible progression of aortopathy [23,24,30,37,38].

If the ascending aorta is incompletely visualized by transthoracic echocardiography or there is disease beyond the ascending aorta, additional imaging should be performed to image the aorta. Magnetic resonance imaging is generally preferred during pregnancy to avoid maternal and fetal radiation exposure. While transesophageal echocardiography (TEE) is another potential option for thoracic aortic imaging, after 18 weeks of gestation, TEE is associated with an increased risk of aspiration and might require intubation, so TEE is generally not used for routine aortic imaging during pregnancy [39].

Measurements of aortic size vary depending on the technique used. Methods for aortic measurement are described separately. (See "Bicuspid aortic valve: General management in adults", section on 'How to monitor'.)

Pharmacologic treatment — All pregnant patients with thoracic aortic dilation should maintain strict blood pressure control to prevent stage 2 hypertension (≥140 mmHg systolic or ≥90 mmHg diastolic) [24,40]. Angiotensin converting enzyme inhibitors and angiotensin II receptor blockers are contraindicated during pregnancy. (See "Treatment of hypertension in pregnant and postpartum patients" and "Adverse effects of angiotensin-converting enzyme inhibitors and receptor blockers in pregnancy".)

Some clinicians administer beta blockers in patients with bicuspid aortic valve and aortic dilation, although supportive evidence is lacking (see "Bicuspid aortic valve: General management in adults", section on 'Pharmacologic therapy'). For pregnant patients with bicuspid aortic valve and aortic root diameter >4.0 cm who do not have moderate or severe aortic regurgitation (AR), we suggest beta blocker therapy. Atenolol use is avoided during pregnancy since it is associated with low birthweight.

Management of AS — If a symptomatic patient with bicuspid severe AS presents early in pregnancy, the patient should be assessed urgently by a pregnancy heart team for optimal management. The patient should receive individualized counseling regarding maternal and fetal risks. If the patient with symptomatic severe AS has one or more high-risk features such as impaired ejection fraction (<50 percent), a transvalvular mean gradient greater than or equal to 40 mmHg, a peak velocity greater than or equal to 4 m/s, or markedly elevated (three times the upper limit of normal) B-type natriuretic peptide (BNP) levels, termination of pregnancy followed by valve intervention should be discussed.

If high-risk features are not present, pregnancy could be continued at a center with an experienced pregnancy heart team with the understanding than an intervention (balloon valvuloplasty, transcatheter aortic valve implantation [TAVI], or cardiac surgery) may be required if there is clinical deterioration during the pregnancy.

Pregnant patients with severe AS and no or only mild symptoms can often be managed conservatively with close clinical observation and management by the pregnancy heart team. Indications for intervention are described below. (See 'For aortic stenosis' below.)

Management of AR — Isolated AR with symptomatic heart failure and/or LV dysfunction can be managed medically during pregnancy with diuretics (eg, furosemide) and vasodilators (eg, hydralazine plus nitrates) [33,41,42]. Angiotensin converting enzyme inhibitors and angiotensin II receptor blockers are contraindicated because of adverse effects on fetal development. (See "Adverse effects of angiotensin-converting enzyme inhibitors and receptor blockers in pregnancy".)

Indication for intervention is described below. (See 'For aortic regurgitation' below.)

Fetal ultrasound — Fetal ultrasound is recommended in pregnancies in females with a bicuspid aortic valve since fetal congenital heart disease has been reported in approximately 4 percent of such pregnancies [22]. Bicuspid aortic valve is frequently associated with congenital abnormalities of the aorta (eg, coarctation of the aorta and patent ductus arteriosus) [2]. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Associated cardiovascular lesions' and 'Risk associated with aortic stenosis' above and "Congenital heart disease: Prenatal screening, diagnosis, and management".)

Intervention during pregnancy — Valve or aortic surgery should be avoided during pregnancy if possible. The maternal risks are similar to those in nonpregnant patients, but cardiopulmonary bypass during pregnancy incurs risks for the fetus, as discussed separately. (See "Pregnancy and valve disease", section on 'Valve surgery and catheter interventions during pregnancy'.)

For patients who require an aortic valve intervention during pregnancy, a catheter-based intervention is an alternative to valve surgery for selected patients [26], as discussed below. (See 'For aortic stenosis' below and 'For aortic regurgitation' below.)

If surgery must be performed during pregnancy (eg, for refractory heart failure caused by severe AS or AR, aortic dissection, or progressive enlargement of the aorta with impending rupture), intervention during the second trimester is preferred when possible to avoid the teratogenic risks of the first trimester and risks of impacting third-trimester delivery. It may be preferable to delay surgery until the fetus is viable, if the patient's condition allows.

Surgery for disease of the aorta — Prophylactic aortic surgery is not performed during pregnancy.

Management of acute aortic dissection in pregnant patients with bicuspid aortic valve is the same as for pregnant patients with heritable thoracic aortic diseases. (See "Heritable thoracic aortic diseases: Pregnancy and postpartum care", section on 'Management of aortic dissection'.)

For aortic stenosis — Intervention for severe AS during pregnancy is reserved for refractory New York Heart Association (NYHA) class III or IV symptoms (table 3).

However, a change in functional status is difficult to assess during pregnancy, since symptoms such as dyspnea, orthopnea, decreased exercise tolerance, and syncope are commonly reported in healthy pregnant patients [26]. Objective measures such as elevations in BNP level [43] and pulmonary artery pressures can help identify patients with worsening hemodynamic status during pregnancy [26]. Since pulmonary artery pressures may be overestimated by echocardiography during pregnancy, some clinicians obtain invasive hemodynamic confirmation of pulmonary hypertension prior to proceeding with an intervention [44,45].

If intervention for AS is required during pregnancy, potential options include percutaneous balloon aortic valvotomy (PBAV), TAVI, and surgical aortic valve replacement (SAVR).

●PBAV avoids the risks of valve replacement and reduces the risks associated with gestation, labor, and delivery [23,46-48]. In this setting, balloon valvotomy may be a potential option even for patients with a calcified aortic valve. Use of transthoracic or transesophageal echocardiographic guidance may avoid the need for fluoroscopy [26].

When PBAV is performed during pregnancy, the goal is to reduce maternal and fetal risk so a conservative approach is appropriate [26]. This involves reducing the aortic gradient by 50 percent while minimizing the risk of inducing acute severe AR (which would require emergency rescue SAVR or TAVI).

However, even in experienced hands, balloon valvotomy can induce AR, recurrent stenosis is common, and the ascending aorta still harbors an abnormal media. (See "Percutaneous balloon aortic valvotomy for native aortic stenosis in adults".)

●TAVI during pregnancy with careful preprocedural planning has been reported [26]. Preoperative and intraoperative two- and three-dimensional transthoracic or transesophageal echocardiography and intravascular ultrasound may enable avoidance of fetal and maternal radiation risk from routine pre-TAVI computed tomography and intraprocedural fluoroscopy. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Transcatheter aortic valve implantation' and "Imaging for transcatheter aortic valve implantation".)

●SAVR during pregnancy is generally avoided given the risk to the fetus. (See "Pregnancy and valve disease", section on 'Valve surgery and catheter interventions during pregnancy'.)

For aortic regurgitation — Aortic valve replacement during pregnancy for AR is reserved for control of refractory NYHA functional class III or IV symptoms (table 3) [33]. General recommendations for aortic valve replacement based on LV cavity size do not apply to pregnant patients. (See "Pregnancy and valve disease", section on 'Valve surgery and catheter interventions during pregnancy'.)

DELIVERY — 

Delivery at a center experienced with high-risk heart disease is recommended for patients with greater than mild AS or dilated aortic diameter (>4.0 cm) [23]. For patients with severe valve disease, intrapartum increases in cardiac output related to contractions may significantly increase the risk of a cardiac event. (See 'Role of pregnancy heart team' above and "Anesthesia for labor and delivery in high-risk heart disease: General considerations".)

Mode of delivery — Controlled vaginal delivery is preferable for most patients. Beta blocker therapy is continued during labor to minimize surges in blood pressure and cardiac output. During vaginal delivery, epidural anesthesia is generally provided to minimize pain and associated cardiovascular changes. (See "Anesthesia for labor and delivery in high-risk heart disease: General considerations", section on 'Vaginal "cardiac delivery"'.)

Cesarean delivery is generally reserved for obstetric or medical indications, including [23,24]:

●Maternal warfarin anticoagulation with a therapeutic international normalized ratio (INR) is an indication for cesarean delivery because the fetus is also anticoagulated, which increases the risk of fetal intracranial hemorrhage. (See "Anticoagulation during pregnancy and postpartum: Agent selection and dosing", section on 'Birth'.)

●For most patients with type A dissection during the third trimester, urgent cesarean delivery is indicated, followed by or with simultaneous aortic repair, as discussed separately. (See "Heritable thoracic aortic diseases: Pregnancy and postpartum care", section on 'Management of aortic dissection'.)

●For most patients with chronic aortic dissection, elective cesarean delivery is performed given concerns for risk of recurrent dissection, aneurysmal enlargement, and aortic rupture [24].

●The mode of delivery is considered on an individualized basis for patients with high-risk cardiovascular features such as enlarging aortic root or ascending aorta ≥4.0 cm (particularly if >4.5 cm) [24], severe AR, or very severe AS (table 1) [49] based upon factors including the patient's hemodynamic status, anticoagulant status, parity, cervical status, gestational age, past obstetric history, and the size of the fetus.

Endocarditis prophylaxis — A bicuspid aortic valve is not considered a lesion requiring endocarditis prophylaxis in the absence of prior endocarditis. In addition, routine antimicrobial prophylaxis for infective endocarditis is not recommended for most patients (with or without heart disease) during pregnancy and delivery. These issues are discussed separately. (See "Pregnancy and valve disease", section on 'Endocarditis prophylaxis'.)

SOCIETY GUIDELINE LINKS — 

Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Management of cardiovascular diseases during pregnancy" and "Society guideline links: Bicuspid aortic valve" and "Society guideline links: Cardiac valve disease" and "Society guideline links: Aortic dissection and other acute aortic syndromes" and "Society guideline links: Congenital heart disease in adults".)

SUMMARY AND RECOMMENDATIONS

●Preconception care – Preconception care for individuals with bicuspid aortic valve who are contemplating pregnancy includes assessment of maternal and fetal risk and counseling by a multidisciplinary pregnancy heart team regarding management of this risk. (See 'Role of pregnancy heart team' above and 'Counseling' above.)

●Evaluation – All patients with bicuspid aortic valve should undergo preconception history, physical examination, transthoracic echocardiography, and cross-sectional aortic imaging (eg, computed tomography or magnetic resonance imaging). (See 'Evaluation' above.)

●Preconception surgery

•Aorta – For individuals with bicuspid aortic valve with aortic diameter ≥5.0 cm, we suggest preconception surgery on the aortic root or ascending aorta (Grade 2C) (algorithm 1). (See 'Risk of aortic complications' above and 'Aortic intervention prior to pregnancy' above and "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Indications for aortic surgery'.)

If cardiac surgery is required for another condition (such as aortic valve replacement for aortic valve disease) a lower aortic diameter threshold (≥4.5 cm) is used. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Indications for aortic surgery'.)

For patients with Turner syndrome, separate specific recommendations for prophylactic aortic surgery apply based upon aortic size adjusted for body size. (See "Management of Turner syndrome in adults", section on 'Aortic dilatation'.)

•Aortic stenosis – Patients with aortic stenosis (AS) with a standard indication for valve intervention (such as symptomatic severe AS regardless of left ventricular ejection fraction [LVEF] or asymptomatic severe AS with LVEF <50 percent) should delay conception until the AS has been addressed. Potential options include percutaneous aortic valvotomy (if the valve is suitable) or aortic valve replacement (typically surgical).

For patients with severe AS who do not endorse any symptoms, we perform exercise testing to assess symptoms and functional capacity and check the plasma B-type natriuretic peptide (BNP) level.

For patients with severe AS with preserved LVEF, regardless of the presence of symptoms, who meet technical criteria for percutaneous balloon valvuloplasty or surgical valvotomy (including a noncalcified valve and no more than mild aortic regurgitation [AR]), we suggest balloon valve intervention or surgical valvotomy prior to conception (Grade 2C). However, careful observation during pregnancy by a pregnancy heart team is a reasonable alternative for patients with severe AS with preserved LVEF and confirmed absence of symptoms (with normal exercise test and plasma BNP level). (See 'AS intervention prior to pregnancy' above.)

•Aortic regurgitation – Patients with severe AR with an indication for aortic valve surgery (including presence of symptoms, marked LV enlargement, or LVEF <50 percent) should undergo aortic valve surgery before pregnancy.

●Surgery during pregnancy – Valve or aortic surgery should be avoided during pregnancy if possible. The maternal risks are similar to those in nonpregnant patients, but cardiopulmonary bypass during pregnancy incurs risks for the fetus. (See "Pregnancy and valve disease", section on 'Valve surgery and catheter interventions during pregnancy'.)

●Delivery – Most patients with bicuspid aortic valve can safely deliver with controlled vaginal delivery. Cesarean delivery is generally reserved for obstetric/medical indications including therapeutic maternal anticoagulation with a vitamin K antagonist (VKA; eg, warfarin) (to mitigate risk of delivery-related intracranial bleeding in the newborn) and maternal type A dissection during the third trimester. (See "Cesarean birth: Preincision planning and patient preparation", section on 'Indications' and "Heritable thoracic aortic diseases: Pregnancy and postpartum care", section on 'Management of aortic dissection'.)

The choice of route of delivery involves shared decision making between the patient and high-risk obstetrician including consideration of the patient's aortic root or ascending aorta size, progressive increase in aortic size, severity of AS or AS, hemodynamic status, anticoagulant status, parity, cervical status, gestational age, past obstetric history, and the size of the fetus. (See 'Mode of delivery' above.)

ACKNOWLEDGMENTS

The UpToDate editorial staff acknowledges Michael R Foley, MD, who contributed to an earlier version of this topic review.

The UpToDate editorial staff acknowledges Joseph K Perloff, MD (deceased), who contributed to an earlier version of this topic review.