Fontan operation is performed to provide palliation for patients with many forms of highly complex congenital heart disease that cannot support a biventricular circulation. Increasing numbers of women who have undergone these connections in childhood are now reaching their childbearing years, and some are becoming pregnant. The low flow and fixed cardiac output of a Fontan circulation poses a number of problems during pregnancy. Here, we report two cases of pregnancy and delivery with Fontan circulation. Case 1, who underwent Fontan procedure for congenital pulmonary atresia with intact vertical septum at age 7, delivered a male infant weighing 1073 g by cesarean section at 286/7 weeks due to massive genital bleeding. Case 2 underwent Fontan procedure for double inlet left ventricle and delivered by vacuum extraction a male infant weighing 2142 g, while monitoring central venous pressure at 375/7 weeks. The former had ascites and dose of diuretic had to be added at early pregnancy, and the latter had no adverse cardiac and obstetric events. These cases suggest that patients after adequate Fontan palliation could complete pregnancy without long-term cardiac sequelae, but might be complicated with cardiac or obstetrical events. Intensive care should be required with specialists, including a neonatologist, anesthesiologist and cardiologist. We have added a literature review of pregnancy with Fontan circulation, referring to previous reports.