What is the management approach for patent ductus arteriosus (PDA) in pregnancy?

Management of Patent Ductus Arteriosus in Pregnancy

Uncomplicated, small or mild patent ductus arteriosus in pregnancy carries minimal maternal risk (WHO Class I) and is generally well-tolerated, while large or hemodynamically significant PDA requires pre-pregnancy evaluation and may necessitate closure before conception. 1

Risk Stratification

The modified WHO classification provides clear guidance for pregnancy risk assessment in PDA patients:

• WHO Class I (Low Risk): Uncomplicated, small or mild PDA without left ventricular volume overload represents no detectable increased risk of maternal mortality and minimal morbidity. 1

• Successfully repaired PDA with no residual shunt also falls into WHO Class I, indicating pregnancy is well-tolerated. 1

• Unoperated moderate-to-large PDA may fall into WHO Class II-III depending on the presence of left atrial/ventricular enlargement, pulmonary hypertension, or significant shunt volume. 1

Pre-Pregnancy Evaluation and Counseling

All women with known PDA should undergo comprehensive cardiovascular assessment before conception to identify any hemodynamic complications that could worsen during pregnancy. 1, 2

Key pre-pregnancy assessments include:

• Echocardiography to visualize the PDA, quantify shunt magnitude, assess left atrial and left ventricular size, and evaluate for pulmonary hypertension. 1

• Measurement of pulmonary artery pressures is critical, as pulmonary hypertension (mean PAP ≥25 mmHg) carries extremely high maternal mortality (17-33%) and represents WHO Class IV (pregnancy contraindicated). 1, 2

• Assessment for left-sided volume overload: Left atrial or left ventricular enlargement indicates hemodynamically significant PDA requiring intervention. 1

Indications for PDA Closure Before Pregnancy

Closure of PDA (percutaneously or surgically) is indicated before pregnancy in the following circumstances:

• Left atrial and/or left ventricular enlargement. 1
• Presence of pulmonary arterial hypertension with net left-to-right shunting. 1
• History of prior endocarditis. 1

Device closure is preferred when anatomically feasible; surgical repair by a congenital heart disease surgeon is recommended when the PDA is too large for device closure or is calcified. 1

Management During Pregnancy

Monitoring Strategy

• Low-risk patients (small PDA without volume overload) require routine follow-up every 3-5 years outside pregnancy, but should have at least one assessment during pregnancy. 1, 2

• Echocardiography should be performed if any new or unexplained cardiovascular symptoms develop during pregnancy. 1, 2

• High-risk patients (those with larger PDAs or complications) require multidisciplinary team management in a specialized center with experienced cardiologists and obstetricians. 1, 2

Medical Management

• No specific medical therapy is required for small, hemodynamically insignificant PDA during pregnancy. 1

• Endocarditis prophylaxis is NOT recommended for repaired PDA without residual shunt or for native PDA during delivery. 1

• If heart failure develops (as can occur with moderate-to-large PDA), standard heart failure management with pregnancy-safe medications is indicated—beta-blockers are relatively safe, while ACE inhibitors and ARBs are contraindicated. 2, 3

Common Pitfall: Coexisting Conditions

Be vigilant for additional factors that can precipitate heart failure in pregnant women with PDA: anemia, preeclampsia, multiple gestation, and infection can all reduce cardiac reserve and unmask previously compensated PDA. 3 Address these aggressively.

Labor and Delivery Planning

Vaginal delivery is recommended as the first choice for most patients with PDA, including those with small-to-moderate defects. 1, 2

• Epidural analgesia is preferred during labor as it stabilizes cardiac output and reduces hemodynamic stress. 2

• Cesarean delivery should be considered only for standard obstetric indications or in the rare circumstance of severe heart failure or Eisenmenger syndrome (right-to-left shunting through PDA with severe pulmonary hypertension). 1, 2

Intrapartum Monitoring

• Continuous maternal vital signs and fetal heart rate monitoring. 2
• Lateral decubitus positioning to optimize venous return. 2
• Avoid fluid overload during IV infusions. 2
• Single dose of intramuscular oxytocin for third stage; ergometrine is contraindicated due to risk of hypertension and pulmonary vasoconstriction. 2

Postpartum Care

Close monitoring for 24-48 hours after delivery is essential due to significant hemodynamic shifts from autotransfusion of blood from the contracted uterus and lower extremities, which can precipitate pulmonary edema in patients with volume-loaded left ventricles. 2

• A single IV dose of furosemide is commonly administered after delivery to manage increased preload. 2

Special Circumstance: Eisenmenger Syndrome

If PDA has progressed to Eisenmenger syndrome (reversed shunt with cyanosis), pregnancy carries extremely high maternal mortality (30-50% in older series, 17-33% more recently) and is WHO Class IV—pregnancy is contraindicated. 1, 2 If pregnancy occurs despite counseling, termination should be discussed; if continued, extraordinary measures including ECMO support may be required, though outcomes remain poor. 4