[Diagnosis of a Twin-Reversed-Arterial-Perfusion-Syndrome (TRAP) in the First Trimester of Pregnancy - Report on Two Cases].

The Twin-Reversed-Arterial-Perfusion-Syndrome (TRAP) is a rare complication of monocygotic multiple pregnancies. It is associated with a high perinatal mortality. One twin (recipient or acardius) is perfused by the other (donour) on the basis of vascular anastomoses. Several possible therapies have been suggested. One of them is the endoscopic laser coagulation of the umbilical artery. The success of this method seems to depend on an early diagnosis of TRAP in the first trimester, when no secondary complications are to be expected. We report the diagnosis of two cases of TRAP in the 12th gestational week by transvaginal ultrasound combined with colour and pulsed Doppler. The latter facilitates the differentiation of TRAP from other pathologic conditions or malformations as well as a detailed description of the blood flow in TRAP.