Ante- and intrapartum diagnosis of vasa praevia in singleton pregnancies by colour coded Doppler sonography

Vasa praevia is a rare complication of pregnancy associated with a high fetal morbidity and mortality. As planned caesarean section can circumvent fetal risks, early detection of vasa praevia is desirable. Antenatal diagnosis by ultrasound by visualisation of vasa praevia may be difficult by transvaginal sonography alone due to an unfavourable angle of insonation. Combination of transabdominal and transvaginal sonography is superior in imaging the placental type, location, insertion of the cord and vasa praevia. We present four cases of antepartum and one case of intrapartum diagnosis of vasa praevia in singleton pregnancies using transabdominal and transvaginal colour coded Doppler sonography. A bipartite placenta with normal cord insertion was found in three cases and with velamentous insertion of the cord in one case. One case had a partially membranous placenta with velamentous insertion of the cord. From the site of cord insertion fetal vessels were coursing over the internal cervical os and then continued in an amniotic sheet to the main placental mass on the opposite uterine wall.