Pregnancy in adults with repaired/unrepaired atrial septal defect

Atrial septal defect (ASD) is the most common form of congenital heart disease. Left-to-right shunting leads to right ventricular (RV) volume overload with excessive pulmonary blood flow. Complications include exercise intolerance, pulmonary vascular disease, RV dysfunction, paradoxical thromboemboli, and atrial arrhythmias. Women with coexisting severe pulmonary hypertension should be counselled against pregnancy due to high incidence of maternal and fetal morbidity and mortality. In the absence of pulmonary hypertension, pregnancy is generally well tolerated in the setting of an ASD. Nevertheless, hemodynamic changes throughout gestation may increase the risk for complications, particularly in those with unrepaired ASDs. Arrhythmias are the most common cardiac event and occur in 4-5%, followed by paradoxical emboli in 2-5%. Obstetrical and neonatal complications include preeclampsia, a higher incidence of infants born small for gestational age, and higher fetal/perinatal mortality. Although there is no definitive evidence demonstrating superiority of an aggressive approach to ASD closure prior to pregnancy, it is currently common practice to electively close asymptomatic but large and/or hemodynamically significant ASDs prior to childbearing. Cardiology follow up during pregnancy should be adapted to clinical circumstances and includes transthoracic echocardiography during the second trimester and arrhythmia monitoring in the event of symptoms.