Bicuspid aortic valve: Management during pregnancy

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".)

DETECTION AND EVALUATION — 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 women of childbearing age because auscultatory signs are inconspicuous or unrecognized [4]. Rarely, a bicuspid aortic valve is first identified during pregnancy or postpartum after a patient presents with dissection of the thoracic aorta [5,6]. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults" and 'Aortic aneurysm and risk of aortic dissection' below.)

All patients with bicuspid aortic valve should undergo preconception transthoracic echocardiography, including assessment for aortic valve dysfunction (AS and AR) and ascending aortic dilation. 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 "Clinical manifestations and diagnosis of Turner syndrome".)

Surveillance of the aorta during pregnancy is discussed below. (See 'Aortic imaging and surveillance' below.)

COUNSELING — Women with bicuspid aortic valve should be counseled prior to and during pregnancy regarding potential risks and their management. Potential risks that should be discussed include heritable congenital heart disease, aortic enlargement or dissection, complications of AS and/or aortic regurgitation (AR), and endocarditis.

The specific role of counseling in women with aortic dilation is discussed below. (See 'Counseling on aortic dilation' below.)

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 cardiovascular defects or aortopathy syndromes. 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 [7,8]. Echocardiographic screening of first-degree relatives is discussed separately. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Genetics'.)

Fetal ultrasound is recommended when the mother has bicuspid aortic valve since fetal congenital heart disease has been reported in approximately 4 percent of women with congenital AS [9]. 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 'Clinical significance' below and "Congenital heart disease: Prenatal screening, diagnosis, and management".)

SURGERY PRIOR TO OR DURING PREGNANCY

Timing — For patients with an indication for valve or aortic surgery, preconception (or postpartum) surgery is preferred to surgery during pregnancy because of the fetal risks of surgery. Valve or aortic surgery should be avoided during pregnancy if possible. The maternal risks are similar to those in nonpregnant women, but cardiopulmonary bypass during pregnancy incurs risks for the fetus. These issues are discussed elsewhere. (See "Pregnancy and valve disease", section on 'Cardiac surgery during pregnancy'.)

Indications for intervention for AS, aortic regurgitation (AR), and aortic dilation prior to pregnancy are aimed at reducing the risk of maternal and fetal complications during and following pregnancy, including the risk of requiring surgery during pregnancy. These indications are discussed below. (See 'Indications for surgery' below and 'Aortic stenosis treatment prior to pregnancy' below and 'Aortic regurgitation treatment prior to pregnancy' below.)

If surgery must be performed during pregnancy (eg, for refractory heart failure [HF] caused by severe AS or AR, aortic dissection, or progressive enlargement of the aorta with impending rupture), intervention during the second trimester is recommended 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.

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 'Aortic stenosis treatment prior to pregnancy' below and 'Aortic regurgitation treatment prior to pregnancy' below.)

Aortic valve replacement for severe AS is performed by surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI), although data on TAVI are more limited in patients with bicuspid aortic valve than in patients with tricuspid valve. (See 'Aortic stenosis treatment prior to pregnancy' below 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'.)

Aortic valve replacement for severe AR associated with bicuspid aortic valve is generally performed by SAVR. (See 'Aortic regurgitation treatment prior to pregnancy' below 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 [10,11]. TAVI involves implantation of a bioprosthetic valve.

The long-term utility of implantation of a bioprosthetic aortic valve in women of childbearing age is not well established (table 1). 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 "Use of anticoagulants during pregnancy and postpartum" 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 women who have undergone the Ross procedure. In a study of eight women 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 [10]. A later study included 33 women who had undergone Ross procedure: 11 women with 18 subsequent pregnancies carried to a gestational age >20 weeks and 22 without subsequent pregnancies [12]. 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.

The least satisfactory option for valve replacement in anticipation of pregnancy is a mechanical prosthesis, which is generally durable but requires life-long 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".)

AORTIC ANEURYSM AND RISK OF AORTIC DISSECTION

Risk of disease of the aorta — Pregnant women 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 [5]. The predisposition to ascending aortic dissection among patients with bicuspid aortic valve reflects an inherent abnormality of the ascending aortic media [5,13]. 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 limited data suggest that the frequency of aortic dissection during pregnancy is low with contemporary management.

●In a multicenter, international registry of patients with bicuspid valves, 23.3 percent of 568 women (mean age 46.6) had some form of aortopathy (dilation of the aortic root only, ascending aorta only, or diffuse) [14]. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Diseases of the aorta'.)

●A retrospective study of 88 women with bicuspid aortic valve identified no dissection or progressive aortic enlargement during pregnancy [15]. In another study, aortic dissection occurred in 2 of 62 completed pregnancies in women with Marfan syndrome but in none of 36 completed pregnancies in women with bicuspid aortic valve [16].

●A study identified 29 women (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) [6]. Among 105 women 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 women 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 women 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 women 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 [17]. 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".)

Aortic imaging and surveillance — All patients with bicuspid aortic valve should undergo transthoracic echocardiography to assess the aortic valve and ascending aortic (aortic root and tubular ascending aorta) size and to assess for coarctation [11,18]. If the thoracic aorta is incompletely visualized by transthoracic echocardiography or there is disease beyond the ascending aorta, additional cross-sectional imaging (magnetic resonance imaging is generally preferred) should be performed to assess aorta size.

In addition, every pregnant woman 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 [18-22]. 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 [23]. 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'.)

It is unknown whether pregnancy changes the natural history of bicuspid-related aortic disease as has been shown in a study of women with Marfan syndrome [24]. In that study, although the pregnancies were uncomplicated, the prevalence of aortic dissection and elective aortic surgery was higher in women 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 [16]. 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 [25].

Counseling on aortic dilation — As noted in the American Association for Thoracic Surgery Consensus guidelines on bicuspid aortic valve-related aortopathy, the aortic size threshold at which pregnancy should be avoided is not known; some have suggested an ascending aorta or aortic root diameter threshold of >4.5 cm, but this is controversial [19]. The 2018 European Society of Cardiology (ESC) guidelines for the management of cardiovascular diseases during pregnancy recommend avoidance of pregnancy when the aorta diameter is >5.0 cm [22]. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'For the ascending aorta'.)

This contrasts with recommendations for pregnancy in women with Marfan syndrome from major societies (American College of Cardiology/American Heart Association and ESC), which suggest avoiding pregnancy in those with enlargement of the aortic root greater than 4.5 cm, since this identifies a particularly high-risk group of individuals with Marfan syndrome. (See "Heritable thoracic aortic diseases: Pregnancy and postpartum care".)

Management of aortic disease

Indications for surgery — For patients with bicuspid aortic valve, recommendations for prophylactic surgical aortic repair/replacement are based on maximal aortic size and other risk factors [19]. The following indications apply to patients with bicuspid aortic valve without Turner syndrome and should be reviewed prior to conception to determine whether prepregnancy 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 most patients with bicuspid aortic valve but without high-risk clinical features, surgery to repair or replace the ascending aorta is indicated at a threshold aortic root or ascending aorta diameter ≥5.5 cm.

High-risk clinical features are aortic coarctation, aortic root aneurysm phenotype [26,27], family history of aortic dissection/sudden death, predominant aortic regurgitation, aortic growth rate >0.3 cm per year on repeated measurements using the same imaging technique at the same aortic level with side-by-side comparison), and uncontrolled hypertension [19,28,29].

●Surgery to repair or replace the aortic root and/or ascending aorta for asymptomatic patients with bicuspid aortic valve is indicated if the diameter of the aortic root or ascending aorta is ≥5.0 cm and at least one of the following applies:

•A high-risk clinical feature for dissection is present.

or

•The patient is at low surgical risk (<4 percent) and the surgery is performed by an experienced aortic surgical team in a center with established expertise in these procedures.

●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 [19].

●For patients with aortic diameter ≥5.0 cm who are contemplating pregnancy, prepregnancy surgical aorta replacement is suggested [19]. The optimum ascending aorta diameter threshold for aortic surgery prior to pregnancy has not been established. Some experts would weigh the potential risks and benefits of surgical repair if the aortic diameter is ≥4.5 cm.

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'.)

Prophylactic aortic surgery is not performed during pregnancy. Management of acute aortic dissection is discussed separately.

General management — All pregnant women with thoracic aortic dilation should maintain strict blood pressure control to prevent stage 2 hypertension (≥140 mmHg systolic or ≥90 mmHg diastolic) [18,30]. 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'). In the absence of specific data, we suggest beta blockers in pregnant women with bicuspid aortic valve and a dilated aorta.

Recommendations for fetal delivery are discussed below. (See 'Delivery' below.)

BICUSPID AORTIC STENOSIS

Clinical significance — AS in women 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) [31]. Mild to moderate bicuspid AS (table 2) is well tolerated during pregnancy because LV systolic function is generally preserved and the LV ejection fraction (LVEF) is usually above normal [32]. (See "Maternal adaptations to pregnancy: Cardiovascular and hemodynamic changes".)

A systematic review of studies published between 1985 and 2019 reported the following rates of complications during pregnancy in women with AS [33]:

●Severe AS – For 103 pregnant women 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 women 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.

The prevalence of fetal congenital heart disease was 5 in 121 pregnancies (4.1 percent) among women with congenital AS in a literature review of studies published between 1985 and 2006 [9].

The importance of aortic abnormalities is discussed above. (See 'Aortic aneurysm and risk of aortic dissection' above.)

Data quantifying maternal and fetal risk during pregnancy in women with high-risk features are limited. HF during pregnancy with severe AS was reported in three of three patients in one series [34] and in 2 of 12 patients in another, with one requiring aortic valve replacement at the end of the first trimester [35]. There are data to suggest that pregnancy has a negative impact on the subsequent natural history of women with congenital AS [36].

Aortic stenosis treatment prior to pregnancy — 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. Also, we suggest valve intervention prior to pregnancy for patients with asymptomatic severe AS with preserved LVEF. These recommendations are consistent with the 2020 American College of Cardiology/American Heart Association valve disease guideline [37]. However, some experts do not require valve intervention prior to pregnancy for patients with severe AS with preserved LVEF and confirmed absence of symptoms (including normal exercise test and serum natriuretic peptide level) [22,37].

Most patients with bicuspid aortic valve with severe AS requiring valve intervention require aortic valve replacement; for young patients, surgical aortic valve replacement (SAVR) is generally preferred, as the long-term durability and effects of transcatheter aortic valve implantation (TAVI) are not yet known. Balloon or surgical aortic valvotomy is an alternative option for only selected patients (generally <25 years old) with noncalcified severely stenotic aortic valves and no more than mild aortic regurgitation [38]. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Procedures for aortic stenosis'.)

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.

Aortic stenosis treatment during pregnancy — If a woman with bicuspid AS presents early in pregnancy with severe AS and/or an LVEF below 40 percent, some experts suggest termination of pregnancy followed by reparative surgery before another attempt at pregnancy.

Alternatively, pregnant women with severe AS and no or only mild symptoms can often be managed conservatively with close clinical observation, bed rest, beta blockers, and oxygen.

Intervention during pregnancy is recommended only for refractory New York Heart Association class III or IV symptoms (table 3). Potential options include balloon aortic valvotomy, TAVI, and SAVR.

●Balloon valvotomy avoids the risks of valve replacement and reduces the risks associated with gestation, labor, and delivery [39-42]. In this setting, balloon valvotomy may be a potential option even for patients with a calcified aortic valve. 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 [43]. 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 'Timing' above.)

BICUSPID 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 [44]. 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'.)

Aortic regurgitation treatment prior to pregnancy — Women 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 women with moderate or severe AR with normal LV function without indications for valve replacement should not undergo prophylactic valve surgery before pregnancy [11,45]. 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".)

Aortic regurgitation treatment during pregnancy — Isolated AR with symptomatic HF and/or LV dysfunction can be managed medically during pregnancy with diuretics and vasodilators [11], such as furosemide and hydralazine plus nitrates [46,47]. 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".)

Aortic valve replacement for AR should be considered during pregnancy only for control of refractory New York Heart Association functional class III or IV symptoms (table 3) [11]. General recommendations for aortic valve replacement based on LV cavity size do not apply to pregnant patients. (See "Pregnancy and valve disease", section on 'Cardiac surgery during pregnancy'.)

DELIVERY

Mode of delivery — Controlled vaginal delivery is preferable for most patients. Cesarean delivery is recommended only for obstetric indications or in the presence of severe cardiovascular disease such as enlarging aortic aneurysm, aortic dissection, severe aortic regurgitation (AR), critical AS, or in the setting of therapeutic vitamin K antagonist (eg, warfarin) anticoagulation (to reduce the risk of delivery-related intracranial bleeding in the newborn) [18,22]. For patients with severe valve disease, intrapartum increases in cardiac output related to contractions may significantly increase the risk of a cardiac event.

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) [22]. (See "Anesthesia for labor and delivery in high-risk heart disease: General considerations".)

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 women (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

●Women with bicuspid aortic valve should receive counseling prior to and during pregnancy. Potential risks should be discussed, including heritable congenital heart disease, aortic dissection (particularly if the ascending aortic diameter is ≥5.0 cm), and complications of aortic stenosis (AS) and/or aortic regurgitation (AR). (See 'Counseling' above.)

●All patients with bicuspid aortic valve should undergo preconception transthoracic echocardiography to assess valve function and the thoracic aorta. If the thoracic aorta is incompletely visualized by transthoracic echocardiography or there is disease beyond the ascending aorta, additional cross-sectional imaging (magnetic resonance imaging is generally preferred) should be performed to assess aorta size. If the aorta is dilated, we recommend serial (eg, monthly or bimonthly if the ascending aorta diameter is ≥4.0 cm; every 12 weeks if the ascending aorta diameter is above normal but <4.0 cm) echocardiographic imaging during pregnancy and for six months postpartum. (See 'Aortic imaging and surveillance' above.)

●For patients with bicuspid aortic valve, recommendations for prophylactic surgical aortic repair/replacement are based on maximal aortic size and other risk factors. These indications for patients should be reviewed prior to conception to determine whether prepregnancy aortic surgery is indicated (algorithm 1). For women with bicuspid aortic valve who are planning pregnancy, we suggest preconception aortic root or ascending aorta surgery if the aortic diameter is ≥5.0 cm (Grade 2C). (See 'Management of aortic disease' above and "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults".)

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'.)

●All pregnant women with bicuspid aortic valve and thoracic aortic dilation should maintain strict blood pressure control to prevent stage II hypertension. (See 'General management' above.)

●For pregnant women with bicuspid aortic valve and aortic root diameter >4.0 cm who do not have moderate or severe AR, we suggest beta blocker therapy (Grade 2C). (See 'Management of aortic disease' above and 'General management' above.)

●Patients with 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).

We suggest valve intervention prior to pregnancy for patients with asymptomatic severe AS with preserved LVEF. However, some experts do not require valve intervention prior to pregnancy for patients with severe AS with preserved LVEF and confirmed absence of symptoms (including normal exercise test and serum natriuretic peptide level) [22,37]. (See 'Aortic stenosis treatment prior to pregnancy' above.)

●Moderate or severe chronic bicuspid AR with preserved LV function is generally well tolerated during pregnancy. (See 'Bicuspid aortic regurgitation' above.)

●Surgery during pregnancy should generally be avoided due to significant fetal risks, although it is indicated if there is severe symptomatic aortic valve disease and if a transcatheter approach is not an option. (See 'Surgery prior to or during pregnancy' above.)

●Controlled vaginal delivery is preferable in the majority of patients. Cesarean delivery is recommended only for obstetric indications or in the presence of severe cardiovascular disease such as aortic dissection, enlarging aortic aneurysm, severe AR, critical AS, or in the setting of therapeutic vitamin K antagonist (eg, warfarin) anticoagulation (to reduce the risk of delivery-related intracranial bleeding in the newborn). (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.