II. Definition

  1. Cord velamentous membrane insertion near cervical os
  2. Fetal blood vessels across presenting membranes

III. Pathophysiology

  1. Blood loss is primarily from fetus
  2. Abnormal fetal vessel insertion
    1. Fetal vessels unsupported by placenta
    2. Velamentous insertion at membranes, not at placenta
    3. Fetal vessels in membranes and tranverse Cervix

IV. Epidemiology

  1. Rare cause of Late Pregnancy Bleeding
  2. Incidence: 1 in 2500 pregnancies

V. Presentation

  1. Bleeding onset at Rupture of Membranes

VI. Risk Factors

  1. Low-lying placenta in second trimester
  2. In Vitro fertilization (IVF)
  3. Bilobed or succenturiate lobe of placenta
  4. Multiple Pregnancy (e.g. Twin Gestation)

VII. Symptoms and signs

  1. Vaginal Bleeding immediately after membrane rupture
  2. Fetal Distress
  3. Vessel may be palpable on cervical exam

VIII. Labs: Only in stable cases

  1. Modified Apt Test
  2. Wright's stain

IX. Radiology

  1. Transvaginal Ultrasound with color flow doppler
    1. Differentiate from Umbilical Cord
    2. Consider in stable cases with suspected Vasa Previa
    3. Not indicated for general screening

X. Management: Emergent

  1. See Late Pregnancy Bleeding
  2. Heavy bleeding or non-reassuring Fetal Heart Tones
    1. Requires immediate delivery
    2. Do not delay delivery for labs or Ultrasound
  3. Immediate fluid resucitation of fetus on delivery
    1. IV or umbilical line: 10-20 cc NS bolus

XI. Prognosis

  1. High perinatal mortality from fetal Exsanguination: 50%

XII. Resources

  1. Vasa Previa Foundation
    1. http://vasaprevia.org

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