With progress in paediatric cardiac surgery and improved management of complex congenital heart lesions, many more children are surviving to adulthood and considering reproduction. In pregnancy clinics in the Western world, congenital heart disease now accounts for the majority of patients with heart conditions.
Francois Fontan described his operation for tricuspid atresia in 1971. With various modifications it has now been adapted for previously untreatable congenital cardiac conditions in which there is only one effective ventricle. The systemic venous blood is channelled directly to the pulmonary arteries and flow depends on an adequate preload and low pulmonary artery pressures.
Women contemplating pregnancy after a Fontan operation need to be carefully assessed because of significant maternal and foetal risks. Arrhythmias, heart failure, thromboembolism, pregnancy related bleeding and hypoxaemia are common in the mother. Foetal risks include miscarriage, prematurity, small for gestational age and neonatal deaths.
Anticoagulant therapy is usually necessary to prevent thrombus is the Fontan circuit. Blood loss diminishes preload resulting in significant impairment of cardiac output. Epidural anaesthesia is preferred as positive pressure ventilation impairs pulmonary flow.
Extensive pre-pregnancy counselling, careful medical supervision and appropriate planning for delivery with a skilled multi-disciplinary team is advisable.