Parasitic acardiac twin: a rare anomaly of monochorionic TRAP sequence

Acardiac twin is a rare complication of monozygotic multiple pregnancy. Vascular anastomosis between twins, with single placenta leads to transfer of deoxygenated blood from umbilical artery of donor to the recipient twin in reverse direction through its umbilical artery which is responsible for abnormal growth. Acardiac twin dies in utero or immediately after birth with a 50-75% mortality of normal donor twin due to congestive heart failure secondary to strain of perfusing acardiac twin.