vasa previa
Pronunciation: VAY-sa PREE-via
Condition where unprotected fetal blood vessels cross the cervical os ahead of the presenting part, creating risk of vessel rupture during delivery.
Full Definition
A rare but potentially catastrophic obstetric condition where fetal blood vessels from velamentous cord insertion or accessory placental lobes traverse the membranes over the cervical os, lying in the path of the presenting fetal part. These unprotected vessels lack Wharton's jelly support and are at risk of compression or rupture when membranes rupture or during labor. The condition is associated with significant perinatal mortality if undiagnosed, but outcomes are excellent when diagnosed prenatally and managed with elective cesarean delivery before labor. Diagnosis relies on transvaginal color Doppler ultrasound to identify vessels crossing the internal cervical os.
Usage
Usage note: Always requires cesarean delivery to prevent vessel rupture and fetal exsanguination.
In Context
- "Transvaginal Doppler confirmed vasa previa with vessels crossing directly over the cervical os." — Ultrasound report
- "The patient was counseled about vasa previa and the need for elective cesarean delivery at 35 weeks." — Counseling documentation