title: Vasa praevia: ultrasound diagnosis at the mid-trimester scan.
abstract: Background: Vasa praevia is a condition in which fetal vessels, unsupported by the umbilical cord or placenta, run on the fetal membranes in the lower uterine segment near the cervix. Rupture of these vessels prior to or at the time of delivery is associated with a very high perinatal mortality rate. Antenatal diagnosis of this condition with ultrasound is readily available, alters management and significantly decreases the risk of fetal loss.Materials and methods: We describe our experience of diagnosing vasa praevia at a tertiary referral ultrasound centre. The ultrasound characteristics that led to the diagnosis of vasa praevia and associated risk factors will be discussed. A guide to aid sonographers when performing an obstetric examination to help screen for this condition has been included.Conclusions: Where suspicion of vasa praevia is raised, and cannot be ruled out on transvaginal ultrasound, a third trimester scan is required.
authors.affiliation: Queensland Ultrasound for Women Brisbane Queensland Australia.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Marr
authors.affiliation: Queensland Ultrasound for Women Brisbane Queensland Australia.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Ashton
authors.affiliation: Queensland Ultrasound for Women Brisbane Queensland Australia.
authors.forename: Annmarie
authors.initials: A
authors.lastname: Stemm
authors.affiliation: Queensland Ultrasound for Women BrisbaneQueenslandAustralia; University of Queensland St LuciaQueenslandAustralia; Department of Maternal Fetal Medicine Mater MothersHospital south BrisbaneQueenslandAustralia.
authors.forename: Robert
authors.initials: R
authors.lastname: Cincotta
authors.affiliation: Queensland Ultrasound for Women BrisbaneQueenslandAustralia; University of Queensland St LuciaQueenslandAustralia; Department of Maternal Fetal Medicine Mater MothersHospital south BrisbaneQueenslandAustralia.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Chua
authors.affiliation: Queensland Ultrasound for Women BrisbaneQueenslandAustralia; University of Queensland St LuciaQueenslandAustralia; Department of Maternal Fetal MedicineRoyal Brisbane Women's Hospital HerstonQueenslandAustralia.
authors.forename: Gregory
authors.initials: G
authors.lastname: Duncombe
keywords: fetal vessels; low lying placenta; mid‐trimester scan; placenta praevia; succenturiate lobe; ultrasound; vasa praevia; velamentous cord insertion