Twin Reversed Arterial Perfusion Sequence: A Case Report and Literature Review

Twin reversed arterial perfusion sequence (TRAPS) is one of the complications of monochorionic twin gestation. It is characterised by large intertwined arterial-arterial anastomosis in which blood flows from one twin (pump twin) to the other twin (perfused twin) in a retrograde pattern.

We report a case of monochorionic diamniotic twin gestation complicated by TRAPS in a 38-year-old G4P3 trader who was referred to the antenatal clinic of Rivers State University Teaching Hospital on account of unusual abdominal distension of one-week duration at 31 weeks gestational age. Ultrasound scan done at presentation showed a monochorionic diamniotic twin with the first twin in a transverse lie with an estimated foetal weight of 1.7kg, foetal heart rate of 150beats per minute, and Twin 2, had no foetal head, no cardiac pulsation with significant tissue swelling. A diagnosis of TRAPS was made for which she was admitted and delivered by emergency caesarean section. The pump twin was admitted into the Special Care Baby Unit (SCBU) and succumbed to cardiac failure 24 hours after delivery.

Monochorionic pregnancy complicated by TRAPS is associated with poor foetal outcomes. Early diagnosis and adequate management will enhance clinical outcomes. The diagnosis of TRAPS requires a high index of suspicion. Clinicians and radiologists need to be aware of the features in order to make prompt diagnosis and take appropriate action which may include early referral to the fetal medicine unit for appropriate intervention and improved outcome for the pump twin.