Twin reversed arterial perfusion (TRAP) sequence in a low – resource setting: a case report from South Sudan

Abstract

Twin reversed arterial perfusion (TRAP) sequence, also known as acardiac twinning, is a rare complication unique to monochorionic twin pregnancies in which a structurally normal “pump” twin supplies circulation to a severely malformed, non-viable “acardiac” twin through abnormal placental vascular anastomoses. The increased cardiac workload places the pump twin at risk of high-output cardiac failure, polyhydramnios, preterm birth, fetal growth restriction, and intrauterine death. Early antenatal diagnosis permits fetal intervention in specialized centres; however, such services are largely unavailable in many low-resource settings. We report the case of a 32-year-old gravida 5 para 4 woman from rural South Sudan who presented in established labour without prior antenatal care. Gestational age was estimated clinically at 37 weeks because reliable menstrual dating and first-trimester ultrasonography were unavailable. A live female pump twin weighing 1.2 kg was delivered vaginally, followed by a 5 kg acardiac twin with characteristic gross morphological features consistent with TRAP sequence. The mother had an uncomplicated postpartum recovery. The pump twin required only routine neonatal care and remained clinically stable throughout hospitalization without evidence of cardiac compromise before discharge after one week. Histopathological examination and long-term follow-up were not feasible because of resource limitations. This case demonstrates that favourable maternal and short-term neonatal outcomes are possible in selected cases of TRAP sequence despite delayed diagnosis and the absence of fetal intervention. It highlights the importance of improving access to antenatal ultrasound, strengthening referral systems, and expanding perinatal care in resource-limited settings. Reporting such cases contributes valuable evidence on the natural history and management of TRAP sequence where advanced fetal therapy is unavailable.