NCIt definition : A severe form of twin-twin transfusion syndrome that occurs in monochorionic pregnancies.
The normal twin (pump twin) supplies the blood flow to its sibling that lacks heart
or brain or both (acardiac/acephalic twin). Untreated, it may lead to the demise of
the pump twin in some cases.;
Alternative definition : NICHD: 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.;