Cardiac disease during pregnancy is associated with 15% maternal mortality and is the most common non-obstetric cause of maternal death. Neonatal and maternal cardiovascular complications are more frequent amongst pregnant women with heart disease, so it is important to know the risk factors and the underlying physiopathology to plan for multidisciplinary perioperative optimization. The physiological changes in pregnancy can be deleterious to patients with Fontan circulation, because rely on preload due to their impossibility of increasing their systolic volume, determining a higher risk of maternal and fetal complications. We report a case of pregnancy in a patient with congenital heart disease and single ventricle secondary to surgically corrected tricuspid and pulmonary atresia in Fontan stage. There were no maternal complications. The birth was scheduled by caesarean section at 32 weeks of gestation. The mother was discharged 48 hours after cesarean section.