Vasa praevia Flashcards
What is vasa praevia?
A condition where the foetal vessels are within the foetal membranes (chorioamniotic membranes) and travel across the internal cervical os.
What is the foetal membrane and foetal vessels?
The foetal membranes surround the amniotic cavity and developing foetus.
The foetal vessels consist of the two umbilical arteries and single umbilical vein.
Meaning of vasa praevia?
Vasa praevia is where the vessels are placed over internal cervical os, before the foetus.
Pathophysiology of vasa praevia?
Usually the umbilical cord containing the foetal vessels (umbilical arteries and vein) inserts directly into the placenta.
In vasa praevia the foetal vessels are always protected, either by the umbilical cord or by the placenta.
In vasa praevia, the foetal vessels are exposed, outside the protection of the umbilical cord or the placenta.
What is the problem with the exposed foetal vessels?
These exposed vessels are prone to bleeding, particularly when the membranes are ruptured during labour and at birth.
This can lead to dramatic foetal blood loss and death.
What are the 2 types of vasa praevia?
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
What are the risk factors for vasa praevia?
Low lying placenta
IVF pregnancy
Multiple pregnancy
How can vasa praevia be diagnosed during pregnancy and why is this ideal?
Diagnosed by ultrasound
This is the ideal scenario, as it allows a planned caesarean section to reduce the risk of haemorrhage.
However, ultrasound is not reliable, and it is often not possible to diagnose antenatally.
What can vasa praevia typically present with?
It may present with antepartum haemorrhage, with bleeding during the second or third trimester of pregnancy.
When can vasa praevia typically be detected?
It may be detected by vaginal examination during labour, when pulsating foetal vessels are seen in the membranes through the dilated cervix.
Can vasa praevia be detected during labour?
Yes
It may be detected by vaginal examination during labour, when pulsating fetal vessels are seen in the membranes through the dilated cervix.
Management for asymptomatic vasa praevia?
Corticosteroids, given from 32 weeks gestation to mature the fetal lungs
Elective caesarean section, planned for 34 – 36 weeks gestation
What is the management for vasa praevia when antepartum haemorrhage occurs?
Where antepartum haemorrhage occurs, emergency caesarean section is required to deliver the foetus before death occurs.
What is the main classic triad of symptoms for vasa praevia?
Painless vaginal bleeding
Rupture of membranes
Foetal bradycardia (or resulting foetal death).
