Vasa praevia

Question 1

What is Vasa Praevia?

Answer 1

• Pathophysiology:
o Foetal vessels course through membrane over the internal cervical os and below foetal presenting part, unprotected by placental tissue or umbilical cord -> when baby descends, they can rupture the vessels
o Type 1 VP = velamentous cord insertion in a single or bilobed placenta
o Type 2 VP = foetal vessels running between lobes of a placenta with 1 or more accessory lobes
o Benckaiser’s haemorrhage = the haemorrhage of blood when the vessels are ruptured

Question 2

What are the RFs for Vasa praevia?

Answer 2

o Foetal anomaly (bilobed placenta or succenturiate lobes)
- Foetal vessels run through the membranes joining separate lobes together
o History of low-lying placenta in 2nd trimester
o Multiple pregnancies
o IVF

Question 3

What are the S/S of vasa praevia?

Answer 3

o Typical picture = ROM -> fresh PV bleeding + foetal bradycardia
 After the membranes rupture, the veins alone can’t hold the weight of the baby -> bleeding
o Foetal HR abnormalities – decelerations, bradycardia, sinusoidal trace, foetal demise
o O/E -> you can palpate the vessels in the membranes, amnioscope can directly visualise this

Question 4

What are the Ix for Vasa praevia?

Answer 4

o Kleihauer test (measures amount of foetal Hb in a mother’s bloodstream)
o Haemoglobin electrophoresis – identify if foetal or maternal blood (takes a long time)
o Doppler USS

Question 5

What is the Mx of Vasa Praevia?

Answer 5

CS

Question 6

What are the complications of Vasa Praevia?

Answer 6

o No major maternal risk but dangerous for the foetus
o Foetus -> the loss of relatively small amounts of blood can have major implications for the foetus = rapid delivery + aggressive resuscitation including use of blood transfusion if required are essential
o Prognosis – foetal mortality if presenting with haemorrhage is 60% but if identified antenatally its 3%