NCIt definition : A condition which occurs in monozygotic twins in which one of the fetuses supplies
the majority of the cardiac output to its co-twin through its umbilical artery. The
recipient twin has only rudimentary organs and structure and is not viable.;
Alternative definition : NICHD: A disorder that results from monozygotic twins unequally sharing blood flow
through their common placenta. It is characterized by placental vascular communications,
and one twin that is Designated as the donor and the other as the recipient. There
is polyhydramnios in the recipient twin and oligohydramnios in the donor twin.;