The North American fetal therapy network consensus statement

Owing to vascular connections within a single placenta, monochorionic gestations present distinctive prenatal management challenges. Complications that can arise as a result of unbalanced hemodynamic exchange (twin-twin transfusion syndrome and twin anemia polycythemia sequence) and unequal placental sharing (selective fetal growth restriction) should be kept in mind while prenatal management is being planned. Because of unique monochorionic angioarchitecture, what happens to one twin can directly affect the other. Death of one twin can result in death or permanent disability of the cotwin. Early detection of these unique disease processes through frequent ultrasonographic surveillance may allow the opportunity for earlier referral, intervention, or both and potentially better outcomes. Therefore, monochorionic gestations should be managed differently than dichorionic gestations or singletons. The purpose of this document is to present in detail methods for monitoring and management of uncomplicated monochorionic gestations and to review the evidence for the roles of these methods for detection of complications in clinical practice. Finally, we present evidence-based and expert opinion-supported recommendations developed by the North American Fetal Therapy Network for the diagnosis, surveillance, and delivery of uncomplicated monochorionic gestations.