How should a pregnant woman with valvular heart disease be managed, considering the type and severity of the valve lesion, New York Heart Association functional class, gestational age, and whether she has a mechanical or bioprosthetic valve?

Management of Valvular Heart Disease in Pregnancy

All pregnant women with valvular heart disease should be managed in a tertiary care center with a dedicated multidisciplinary Heart Valve Team consisting of cardiologists, cardiac surgeons, anesthesiologists, and maternal-fetal medicine obstetricians experienced in high-risk cardiac conditions. 1

Pre-Pregnancy Evaluation and Counseling

Every woman with suspected or known valvular heart disease must undergo clinical evaluation and transthoracic echocardiography before pregnancy. 1

• All patients with severe valve disease (stages C and D) require prepregnancy counseling by a cardiologist with expertise in managing VHD during pregnancy 1
• Women considering valve replacement before pregnancy must receive detailed counseling about mechanical versus bioprosthetic valve options, including implications for future pregnancies and anticoagulation requirements 1
• Pregnancy should be discouraged in women with severe symptomatic stenotic lesions, severe regurgitation with LV dysfunction (EF <0.40), pulmonary hypertension >75% of systemic pressure, or NYHA class III-IV symptoms until corrective intervention is performed 1

Management of Specific Valve Lesions During Pregnancy

Mitral Stenosis

Severe mitral stenosis (valve area ≤1.5 cm²) poses the highest risk during pregnancy and requires aggressive management. 1, 2

Medical Management

• Beta-blockers (metoprolol or propranolol, NOT atenolol) are first-line for rate control to optimize diastolic filling time 1, 2
• Diuretics should be added cautiously for pulmonary congestion, avoiding excessive volume depletion that could compromise uteroplacental perfusion 1, 2
• Bed rest provides additional symptomatic benefit 2

Interventional Management

• Percutaneous balloon mitral commissurotomy is reasonable for pregnant patients with severe MS who remain NYHA class III-IV symptomatic despite optimal medical therapy, provided valve morphology is favorable (minimal calcification, good leaflet mobility, minimal subvalvular disease) 1, 2
• The procedure should be performed after 20 weeks gestation when possible, using the Inoue balloon technique with abdominal shielding, minimal fluoroscopy, and continuous fetal monitoring 2
• For unfavorable valve morphology, intervention is reasonable only for refractory NYHA class IV symptoms 1
• Valve surgery should NOT be performed in the absence of severe heart failure symptoms, as it carries 30-40% fetal mortality and up to 9% maternal mortality 1, 2

Aortic Stenosis

Severe aortic stenosis (mean gradient ≥40 mm Hg or aortic velocity ≥4.0 m/s) requires intervention before pregnancy if symptomatic. 1

• Asymptomatic patients with severe AS should undergo valve intervention before pregnancy 1
• During pregnancy, valve intervention is reasonable only if hemodynamic deterioration occurs or NYHA class III-IV symptoms develop 1
• Careful attention to avoid hypotension is critical, as these patients are preload-dependent 1

Valve Regurgitation (Mitral or Aortic)

Most patients with severe regurgitation can be managed conservatively during pregnancy unless refractory NYHA class IV heart failure develops. 1

Medical Management

• ACE inhibitors and ARBs are absolutely contraindicated throughout pregnancy due to fetal renal dysplasia, oligohydramnios, growth retardation, and skeletal abnormalities 1
• Hydralazine is the preferred vasodilator if afterload reduction is needed 3
• Diuretics may be used cautiously for pulmonary congestion 3

Surgical Considerations

• Valve surgery during pregnancy is reserved exclusively for refractory NYHA class IV symptoms and carries extremely high fetal (30-40%) and maternal (up to 9%) mortality 1, 3
• Valve repair before pregnancy may be considered in asymptomatic severe MR with suitable valve anatomy after detailed risk-benefit discussion 1

Management of Prosthetic Valves in Pregnancy

Bioprosthetic Valves

Bioprosthetic valves are preferred in women of childbearing age to avoid anticoagulation-related fetal risks, despite concerns about accelerated structural degeneration during pregnancy. 4

• All patients require clinical evaluation and baseline TTE before pregnancy 1
• Repeat TTE should be performed if symptoms develop during pregnancy 1
• Low-dose aspirin (75-100 mg daily) is recommended in the second and third trimesters 1

Mechanical Valves

Pregnancy with a mechanical prosthetic valve is extremely high-risk, and there is no anticoagulation strategy that is consistently safe for both mother and baby. 1

Anticoagulation Strategy

The choice of anticoagulation regimen requires shared decision-making with full disclosure that warfarin minimizes maternal risk but maximizes fetal risk, while heparin-based regimens do the opposite. 1

First Trimester Options:

Option 1 (Lower maternal risk, higher fetal risk):

• Continue warfarin throughout first trimester if dose ≤5 mg/day to maintain therapeutic INR 1
• This approach carries lowest maternal thrombosis risk but highest fetal risk (warfarin embryopathy, miscarriage) 1, 5

Option 2 (Higher maternal risk, lower fetal risk):

• Switch to dose-adjusted LMWH twice daily (target anti-Xa 0.8-1.2 U/mL at 4-6 hours post-dose) if warfarin dose >5 mg/day 1
• Critical caveat: LMWH during first trimester is associated with significantly higher rates of prosthetic valve thrombosis, heart failure, arrhythmias, and endocarditis compared to warfarin 5

Second and Third Trimesters:

• Warfarin should be resumed after first trimester and continued until at least 1 week before planned delivery 1
• Low-dose aspirin (75-100 mg daily) must be added 1

Peripartum Management:

• Switch from warfarin to LMWH at least 1 week before planned delivery 1
• Switch from LMWH to unfractionated heparin (aPTT 2× control) at least 36 hours before planned delivery 1
• Stop UFH at least 6 hours before vaginal delivery 1
• If labor begins while therapeutically anticoagulated with warfarin, perform cesarean section after warfarin reversal 1

Monitoring Requirements:

• TEE should be performed for suspected prosthetic valve obstruction or embolic events 1
• Frequent INR monitoring (weekly or more often) is mandatory 1
• Patients who cannot maintain therapeutic anticoagulation with frequent monitoring should be counseled against pregnancy 1

Delivery Planning

Mode of Delivery

• Vaginal delivery is preferred for most patients with valvular heart disease unless obstetric indications dictate cesarean section 1, 3
• Epidural analgesia is recommended to blunt catecholamine surges and stabilize hemodynamics 3
• Assisted second stage (forceps/vacuum) may limit prolonged Valsalva in symptomatic patients 3

Postpartum Monitoring

• The first 24-48 hours postpartum are highest risk due to autotransfusion from uterine involution causing rapid hemodynamic shifts 3
• Continue cardiac monitoring for at least 24 hours in symptomatic patients 3
• Monitor for arrhythmias, heart failure decompensation, and hemorrhagic complications 3

Critical Pitfalls to Avoid

• Never use ACE inhibitors or ARBs during pregnancy 1
• Never perform elective valve surgery during pregnancy in the absence of severe intractable heart failure 1
• Never underestimate the thrombotic risk of mechanical valves with subtherapeutic anticoagulation—prosthetic valve thrombosis is more common with MVR and with heparin-based regimens during first trimester 5
• Never use atenolol for rate control due to intrauterine growth restriction risk 3
• Never assume gradients accurately reflect stenosis severity during pregnancy—measure valve area, as gradients are elevated by increased cardiac output 1