2018 27b Vasa Praevia Flashcards
How should undiagnosed vasa praevia be managed at delivery?
- Emergency CS
- Neonatal resuscitation
- Blood transfusion if required
- Placental pathological examination to confirm diagnosis
How is vasa praevia diagnosed antenatally?
- Routine fetal anomaly scan: high diagnostic accuracy, low false positives
- Combination of TA & TV colour Doppler for best accuracy
Should we screen for vasa praevia?
- Insufficient evidence to support universal screening for all
- Targeted mid-pregnancy ultrasound may reduce perinatal loss, more evidence needed
How should women with vasa praevia be managed?
- Confirm with 3rd trimester USS
- Corticosteroids from 32/40
- Consider admission from 30-32/40
- ElCS 34-36/40 if asymptomatic
- EmCS if PROM or signs of labour
What is vasa praevia?
Fetal vessels run through free placental membranes, unprotected by placental tissue or Wharton’s jelly & liable to rupture in labour
What are the 2 classifications of vasa praevia?
Type 1: vessel connected to velamentous umbilical cord
Type 2: vessel connects placenta with succenturiate or accessory lobe
What are the fetal mortality rates for vasa praevia?
60% if diagnosed in labour
<5% if diagnosed antenatally
How does undiagnosed vasa praevia present?
- Painless dark red vaginal bleeding (Benckiser’s haemorrhage)
- Particularly with ROM or Cx dilation
- Acute fetal compromise
- Pulsating fetal vessels in internal os
What is the incidence of vasa praevia?
1:2000-1:5000
What is the total fetal blood volume?
80-100ml/kg
What are the risk factors for vasa praevia?
- Placenta praevia
- Bilobed placenta
- Succenturiate placental lobes
- Assisted conception
- Velamentous cord insertion
What proportion of vasa praevia cases resolve?
20%
Particularly if LLP
