vasa praevia
Pronunciation: VAH-sah PRAY-vee-ah
Rare condition where fetal blood vessels cross the cervical opening ahead of the presenting part.
Full Definition
Vasa praevia is a rare but potentially catastrophic obstetric condition where unprotected fetal blood vessels cross the internal cervical os ahead of the presenting fetal part. These vessels lack the protection of placental tissue or umbilical cord and are at risk of rupture during labour or when membranes rupture, leading to rapid fetal exsanguination. The condition is associated with velamentous cord insertion and accessory placental lobes. Antenatal diagnosis through ultrasound allows for planned caesarean section before labour, significantly improving fetal outcomes.
Usage
Usage note: British spelling 'praevia' vs American 'previa' - maintain consistency with placenta praevia.
In Context
- "Doppler ultrasound identified vasa praevia requiring elective caesarean delivery." — Antenatal diagnosis report
- "The presence of vasa praevia contraindicated vaginal delivery due to bleeding risk." — Delivery planning documentation