Twin Pregnancy in Patient With Fontan Circulation and Homozygous MTHFR Mutation

Singleton pregnancy in Fontan patients is burdened by a significant maternal cardiovascular and obstetric risk. The cardiac workload in a twin pregnancy is greater and could place Fontan-palliated patients at an increased risk of complications. We report a case of a woman with Fontan circulation and homozygous MTHFR mutation who had a twin pregnancy.