II. Definition
- Cord velamentous membrane insertion near cervical os
- Fetal blood vessels across presenting membranes
III. Pathophysiology
- Blood loss is primarily from fetus
- Abnormal fetal vessel insertion
- Fetal vessels unsupported by placenta
- Velamentous insertion at membranes, not at placenta
- Fetal vessels in membranes and tranverse Cervix
IV. Epidemiology
- Rare cause of Late Pregnancy Bleeding
- Incidence: 1 in 2500 pregnancies
V. Presentation
- Bleeding onset at Rupture of Membranes
VI. Risk Factors
- Low-lying placenta in second trimester
- In Vitro fertilization (IVF)
- Bilobed or succenturiate lobe of placenta
- Multiple Pregnancy (e.g. Twin Gestation)
VII. Symptoms and signs
- Vaginal Bleeding immediately after membrane rupture
- Fetal Distress
- Vessel may be palpable on cervical exam
VIII. Labs: Only in stable cases
- Modified Apt Test
- Wright's stain
IX. Radiology
-
Transvaginal Ultrasound with color flow doppler
- Differentiate from Umbilical Cord
- Consider in stable cases with suspected Vasa Previa
- Not indicated for general screening
X. Management: Emergent
- See Late Pregnancy Bleeding
- Heavy bleeding or non-reassuring Fetal Heart Tones
- Requires immediate delivery
- Do not delay delivery for labs or Ultrasound
- Immediate fluid resucitation of fetus on delivery
- IV or umbilical line: 10-20 cc NS bolus
XI. Prognosis
- High perinatal mortality from fetal Exsanguination: 50%
XII. Resources
- Vasa Previa Foundation