Secuencia TRAP. Diagnóstico diferencial con gemelo muerto

Abstract

TRAP sequence occurs in 1% of monochorionic twin pregnancies. We present an atypical case of TRAP sequence in which the acardiac twin was properly formed and the cranial and cardiac structures could be identified. The differential diagnosis between TRAP phenomenon and intrauterine death of one twin was performed on the basis of other suspicious ultrasound signs, such as the presence of a single umbilical artery, a dorsal hygroma, and a short cord. The definitive diagnosis was established by Doppler, which showed an arterio-arterial anastomosis and reverse flow in the dead twin.We believe that the presence of a TRAP phenomenon should be taken into account in cases of ultrasound diagnosis of a monochorionic pregnancy with intrauterine demise of one twin. The finding of cranial structures and heart does not exclude a diagnosis of TRAP.