Vasa praevia
（重定向自Vasa previa）
Vasa praevia (vasa previa AE) is an obstetric complication in which fetal blood vessels cross or run near the internal orifice of the uterus. These vessels are at risk of rupture when the supporting membranes rupture, as they are unsupported by the umbilical cord or placental tissue.The term "vasa previa" is derived from the Latin; "vasa" means vessel and "previa" comes from "pre" meaning "before" and "via" meaning "way". In other words, vessels lie before the baby in the birth canal and in the way.