Twin anemia-polycythemia sequence

Definition

A rare disorder related to monochorionic twin pregnancy characterized by unbalanced inter-twin blood transfusion with subsequent anemia in the donor and polycythemia in the recipient twin. Amniotic fluid abnormalities are absent. Doppler measurement of middle cerebral artery peak systolic velocities reveals significantly discordant velocities. The condition can occur spontaneously or complicate incomplete fetoscopic laser surgery.