Vasa Praevia

Question 1

Vasa praevia pathophysiology

Answer 1

The fetal vessels are exposed, outside the protection of the umbilical cord or the placenta.

The fetal vessels travel through the chorioamniotic membranes, and pass across the internal cervical os (the inner opening of the cervix).

These exposed vessels are prone to bleeding

Question 2

Where are the fetal vessels found

Answer 2

Within the umbilical cord which inserts directly into the placenta

Question 3

Fetal vessels

Answer 3

2 umbilical arteries and vein

Question 4

What protects the fetal vessels

Answer 4

Wharton’s jelly - layer of soft connective tissue

Question 5

Velamentous umbilical cord

Answer 5

Where the umbilical cord inserts into the chorioamniotic membranes, and the fetal vessels travel unprotected through the membranes before joining the placenta

Question 6

Succenturiate lobe

Answer 6

An accessory lobe of the placenta

Connected by fetal vessels that travel through the chorioamniotic membranes between the placental lobes.

Question 7

When is antepartum haemorrhage most likely to occur

Answer 7

When the membranes are ruptured during labour

At birth

Question 8

Risks of vasa praevia

Answer 8

Antepartum haemorrhage
Fetal blood loss
Death

Question 9

Types of vasa praevia

Answer 9

Type I vasa praevia – the fetal vessels are exposed as a velamentous umbilical cord

Type II vasa praevia – the fetal vessels are exposed as they travel to an accessory placental lobe

Question 10

Risk factors for vasa praevia

Answer 10

Low lying placenta
IVF
Multiple pregnancy

Question 11

Presentation of vasa praevia

Answer 11

Can present with antepartum haemorrhage - bleeding within the second or third trimester

During labour:

• fetal distress - bradycardia
• dark red bleeding after rupture of the membranes

Question 12

Investigations for vasa praevia

Answer 12

USS (unreliable)

Often not possible to identify antenatally

Vaginal exam during labour - pulsating fetal vessels are seen in the membranes through the dilated cervix

Question 13

Management of vasa praevia

Answer 13

Planned Caesarean section - 34 - 36 weeks

Corticosteroids at 32 weeks

Question 14

What carries a high fetal mortality

Answer 14

Dark red bleeding after the rupture of membranes

Question 15

Management of antepartum haemorrhage

Answer 15

A-E
Escalate to senior
Transfusion may be needed - G+S and crossmatch
Emergency C - section