A case of twin reversed arterial perfusion (TRAP) sequence in a monochorionic diamniotic triplet pregnancy with two acardiac fetuses

Background: Twin reversed arterial perfusion (TRAP) sequence is a rare anomaly of monochorionic twins involving artery-to-artery anastomoses resulting in a structurally normal “pump” twin that provides circulation to an acardiac twin in a retrograde fashion. Case: Herein we report a rare case of a triplet gestation (TrGA) consisting of two conjoined acardiac TRAP recipients and one surviving normal pump fetus. The TRAP recipients were discordant for their anomalies. We know of only three similar case reports from the literature. Conclusion: Characteristic ultrasound findings allow for the prenatal diagnosis of TRAP sequence and may allow prompt and appropriate treatment to improve the outcome of the pump twin.