Invasive Procedures in Monochorionic Twins

Abstract

Monochorionic twin pregnancies (MC) are less frequent but they are considered higher risk pregnancies compared to dichorionic pregnancies. As a result, determining the chorionicity of a twin pregnancy is of vital importance for the surveillance and management of the pregnancy. The problem originates from the fact that monochorionic twins have one placenta, and as a result the circulation of the two fetuses is closely related to each other mainly through anastomosis of the placenta. The number and type of anastomosis is of great importance for the course of the pregnancy. Diagnosis of chromosomal abnormalities in such pregnancies requires excellent knowledge of invasive procedures and good clinical skills. Monochorionic twins are at increased risk for unique complications including twin-to-twin transfusion syndrome (TTTS), selective intrauterine growth restriction (sIUGR), and twin-reversed arterial perfusion (TRAP) sequence. Twin-to-twin transfusion syndrome is a very well known and described complication of mono chorionic twin pregnancies and must be considered and checked in each monochorionic pregnancy. Selective feticide is not a method used very commonly in MC pregnancies, but may be applied in selected cases. For TTTS laser treatment of the anastomosis is a method of choice, but should be performed in centers with experience.