Twin Reversed Arterial Perfusion Sequence Presenting As An Acephalic Fetus:A Case Report

Background: Twin Reversed Arterial Perfusion (TRAP) sequence is a rare complication of monochorionic twin pregnancy in which an acardiac/acephalic twin is perfused retrogradely by the healthy pump twin, increasing the risk of cardiac overload, polyhydramnios, preterm birth, and fetal demise. This report aims to describe a case of an acephalic fetus in a TRAP sequence and highlight the value of early diagnosis and conservative management. Case Presentation: A 29-year-old gravida 2 presented at 25 weeks with a monochorionic monozygotic twin pregnancy. Ultrasound revealed a structurally normal pump twin and a grossly malformed acephalic co-twin with reversed arterial flow in the umbilical artery, confirming TRAP sequence. Expectant management with two-weekly ultrasounds showed stable cardiac function and normal amniotic fluid in the pump twin. At 36 weeks, due to maternal discomfort and abdominal distension, a caesarean section was performed. The pump twin was delivered healthy (2.5 kg). The acephalic twin was non-viable and larger in weight (3.5 kg). Conclusion: This case demonstrates that conservative monitoring can yield favorable outcomes when the pump twin shows no signs of cardiac compromise. Early ultrasound diagnosis, vigilant follow-up, and coordinated multidisciplinary care are key to optimizing survival in TRAP pregnancies Chatt Maa Shi Hosp Med Coll J; Vol.25 (2); July 2026; Page 111-115