Velamentous insertion of the umbilical cord

This video clip illustrates different types of umbilical cord insertion into the placenta at 11-13 weeks' gestation. The insertion can be central (about 90%), eccentric, marginal or velamentous (about 1%). In the latter the cord inserts into the membranes before entering the placental disk and the vessels crossing the membranes are not mechanically protected by Wharton's jelly or placental tissue. The condition is strongly associated with vasa previa (type one). Consequently, in every case of velamentous insertion of the cord an effort should be made to exclude the presence of the fetal vessels in close proximity of the internal os (vasa previa). In monochorionic twin pregnancies velamentous insertion of the cord is commonly found in cases of twin-to-twin transfusion syndrome. Velamentous umbilical cord insertion can be detected by ultrasound at 11-13 week's gestation by the use of transvaginal or transabdominal approaches. Colour flow mapping is very helpful for the tracing of the umbilical cord connection into placental tissue. Please note that in many cases at 11-13 weeks the amnion is not attached to chorion and the velamentous cord is attached directly to the amniotic membrane.