Managing TRAP Sequence Conservatively: A Case Report of Full-Term Pregnancy With Favorable Outcome.

Acardiac twinning, also known as Twin reversed arterial perfusion (TRAP) sequence, is a rare anomaly seen exclusively in monochorionic twin pregnancies. It occurs due to abnormal placental vascular anastomoses, allowing retrograde perfusion from healthy "pump" twin to severely malformed twin lacking a functional heart. The prognosis is poor; mortality is 100% in the acardiac twin and 50%-55% in the pump twin. We present a case of 30-year-old gravida 3 parity 1 with previous 1 abortion (G3 P1 A1) having an acephalus acardiac twin diagnosed during routine second trimester ultrasound scan. Because there were no signs of hemodynamic compromise in the normal twin and pregnancy was continued up to 38 weeks of gestation when elective lower segment cesarean section was done. This case emphasizes conservative management of TRAP sequence if there is no risk of hydrops or cardiac failure in the pump twin.