Placenta praaevia & accreta GTG + Vasa praevia GTG Flashcards
How common is placenta praaevia?
1 in 200
Low lying placenta is how far from internal Os
<20mm
Placenta praaevia lies directly over internal Os
How common is placenta accreta?
1 in 300-2000
Risk of placenta praaevia after
0 CS
1 in 400 0.24%
Risk of placenta praaevia after
1 CS
1 in 160 0.6%
Risk of placenta praaevia after
2 CS
1 in 60 1.6%
Risk of placenta praaevia after
3 CS
1 in 30 3.3%
Risk of placenta praaevia after
4 CS
1 in 10 10%
What other factors increase risk of placenta praaevia?
ART
Smoking
< 1 year since CS
When to offer repeat USS? What % will resolve by term?
32 weeks
90%
If still present booked 36weeks
Cervical length under 25mm is a predictor of what in praaevia?
APH and EMCS
Main risk with placenta praevia
preterm labour
obstetric haemorrhage
Placenta praecvia and Hx of bleeding +/ risk of preterm delivered
34-36+6
Uncomplicated praevia
36-37weeks
What factors can be used to avoid cutting through placenta at CS?
Pre/intra-op USS
If transverse lie, consider vertical incision
If placenta is cut during delivery, what should happen?
Clamp the cord to avoid excessive fetal blood loss
Risk of emergency hysterectomy CS for PP
emergency hysterectomy, up to 11 in 100 women (very common)
Need for further surgery following CS for PP
● need for further laparotomy during recovery from the caesarean, 75 in 1000 women (common)
Risk of thromboembolic disease following CS for praaevia
3/100
Risk bladder/ureterc injury CS for praevia
6/100
Risk of future placenta praevia
future placenta praevia, 23 in 1000 women (common)
Risk MOH for CS for praaevia
future placenta praevia, 23 in 100 women (common)
If placenta praaevia and previous CS risk of emergency hysterectomy?
● emergency hysterectomy, up to 27 in 100 women (very common)
Risk accreta with placenta praevia after 1CS
3%
Risk accreta with placenta praevia after 2CS
11%
Risk accreta with placenta praevia after 3 CS
40%
Risk accreta with placenta praevia after 4CS
61%
Risk accreta with placenta praevia after 5+CS
> 67%
What % of accreta are not Dx until CS?
1/2 to 1/3
Median blood loss with accreta?
2000-7800mls
Sensitivity and specificity of USS for Dx accreta?
90% sensitive
96% specificity
Confirm with MRI
In RF for preterm delivery, when are placenta accreta spectrum delivered?
35-36 weeks
How should the placenta be delivered with placenta accreta?
CS hysterectomy with placenta in situ
If shallow invasion can consider partial myometrial resection
Leave placenta left in situ
If partial myometrial resection performed for accreta, what are the risks of:
- Secondary hysterectomy
- Mat mortality
31% - secondary hysterectomy
4% matneral mortality
If partial myometrial resection performed for accreta, what are the chances of:
- subsequent pregnancy
- subsequent menstruation
- 73%
- 80%
If placenta left in situ and closed, what is the rate of spontaneous reabsorption?
75%
If unsuspected placenta accreta performed after delivery of baby, what should you do?
Leave placenta in situ
Emergency hysterectomy
What are Type 1 and Type 2 of Vasa praevia?
Type 1: Velamentous umbilical cord
Type 2: Connects placenta with succenturiate or accessory lobe
If ruptured vasa praevia, what is the fetal mortality rate despite EMCS?
60%
What % of vasa praevia are Dx antenatally?
95%
What is the incidence of vasa praevia?
1/1200-1500
Vasa praevia Dx in 2nd trimester, what % resolve by delivery?
When should FU scan be booked?
20%
32/40
When should asymptomatic women with vasa praevia be delivered?
34-36weeks
When should steroids be given?
32 weeks
Can consider prophylactic admission to hospital from which gestation?
30-32 weeks
If known vasa praevia and SROM?
EMCS
