Acardiac twin formation is a rare anomaly. It is one of the most extreme complications of monozygotic twin pregnancies. Such occurrences are brought about when a normal twin donates blood to an abnormal twin through its umbilical arteries via vascular anastomoses at the level of the placenta, which is termed as twin reversed arterial perfusion sequence (TRAPS). Twin reversed arterial perfusion sequence is considered a rare variant of twin-to-twin transfusion syndrome. Due to the considerable blood transfer from the healthy twin to the parasitic one, cardiac failure can ensue in the healthy twin. The mortality of the acardiac twin is 100%. We present an obstetric case of a South Asian female, whose serial ultrasound scans consistently displayed a heterogeneous mass, initially labeled a teratoma. This was postoperatively diagnosed as an acardiac twin due to TRAPS. Thus, we would like to highlight the importance of umbilical artery Doppler in the prompt diagnosis of TRAPS so timely management may be undertaken to prevent morbidity and/or mortality of the normal twin.
Keywords: fetal disease; placental abnormality; pregnancy complications; prenatal ultrasonography; twin reversed arterial perfusion syndrome; umbilical artery doppler.