Single fetal demise in twin gestation.

A single fetal demise in a twin gestation occurs infrequently: it is recognized in fewer than 7% of twins past the first trimester. Increased morbidity is associated primarily with monozygotic twins who have vascular anastomoses associated with diamniotic-monochorionic placentation, and with monoamniotic twins. Morbidity and mortality of these twin gestations potentially can be reduced with identification of the at-risk pregnancy and with intensive antenatal surveillance. The most difficult management problem is the twin-to-twin transfusion syndrome, which will require improved technologic developments to resolve.