Umbilical cord coagulation by operative microendoscopy at 16 weeks' gestation in an acardiac twin.

Twin reversed arterial perfusion (TRAP) sequence carries high mortality and morbidity in the normal twin due to a hemodynamic imbalance through the feto-fetal vascular anastomosis. This report describes the ultrasound features of TRAP in the first trimester and a new technique for selective fetocide in the early second trimester in monochorionic twin pregnancies complicated by the TRAP sequence. Laser coagulation of the umbilical cord of the acardiac twin was performed under sonoendoscopic control. The blood flow in the umbilical cord of the acardiac twin was successfully arrested and the survivor developed normally. TRAP sequence can be recognized in the first trimester and successfully arrested by microendoscopic surgery.