Twin Reversed Arterial Perfusion Sequence Diagnosed Late in the Third Trimester: A Case Report and Literature Review.

The twin reversed arterial perfusion (TRAP) sequence is a rare complication associated with monochorionic twins. It is characterized by blood flow from the umbilical artery of the normal (pump) twin to the umbilical artery of the abnormal (acardiac) twin via artery-to-artery anastomosis. This condition is associated with 100% mortality in the acardiac twin and a high rate of perinatal morbidity and mortality in the pump twin, primarily due to intrauterine hypoxic injury, heart failure, and prematurity.