ABSTRACT
Twin reversed arterial perfusion (TRAP) sequence is a unique complication of monochorionic twinning, in which normal pump or donor twin paradoxically perfuses the recipient or acardiac twin through arterial- arterial anastomoses. This results in reversed flow of poorly oxygenated blood through the recipient twin and is usually associated with partial or complete lack of heart development. The pump twin has a mortality rate of 50% as a result of high-output heart failure, preterm labor, and polyhydramnios. We present here a case of twin reversed arterial perfusion (TRAP) sequence complicated by severe polyhydramnios during the second trimester. The blood supply to acardiac twin was interrupted successfully at 25 weeks of gestation by injecting 1.5 mL of absolute alcohol into the intra-abdominal portion of the single umbilical artery, under ultrasound guidance. Serial ultrasound showed normal growth and normal amniotic fluid volume in normal pump twin, but arrest of growth in femur length and decrease in amniotic fluid volume in acardiac twin. The normal pump twin was delivered at 384 weeks of gestation and had uneventful neonatal course.