VBAC (RANZCOG) Flashcards
Incidence of LSCS in Australia and NZ?
33% Aus, 25.5% NZ 2015
Prepregnancy advice to increase success and safety of VBAC?
IP interval of 18 months
weight reduction
Success rates of VBAC?
60-80% success Middlemore
43% Aus
Factors favouring successful VBAC?
previous safe vaginal birth
previous successful VBAC (87-91%)
spontaneous onset labour
uncomplicated low risk pregnancy
Factors reducing VBAC success?
Previous CS for dystocia IOL coexisting pregnancy/maternal conditions BMI >30 (40%) macrosomia >4kg AMA short stature >1 CS Postdates (RCOG) low pre labour bishop score (RCOG)
What is the difference in incidence of uterine rupture when BMI normal vs. >40? (RANZCOG)
- 9% normal BMI
2. 1% BMI >40
RDS risk VBAC vs. CS
RCOG
VBAC = 2-3%
CS = 4-6%
difference in maternal mortality for VBAC or repeat CS?
VBAC = 0.004%
CS = 0.013%
RCOG
Uterine rupture rate in unscarred vs. scarred uterus? (RANZCOG)
- 5-2/10,000 deliveries in unscarred uterus
- 005-0.02%
vs.
22-74/10,000 deliveries
0.2-0.7%
risk of pathological fetal acidosis after uterine rupture (RANZCOG)
0.15% of VBAC
90% after uterine rupture.
Risk of perinatal death with uterine rupture (RANZCOG)
4 per 10,000 (0.04%) 1/3 attributable to uterine rupture
Elective cs = <1/10,000 perinatal death
Risk after uterine rupture is 12% (UKOSS), 2-16% AHRQ
risk of maternal death with uterine rupture (RANZCOG)?
UKOSS: 1.3% with uterine rupture.
RANZCOG: 0.02 per 1000 women attempting VBAC (2/100,000)
0.002%
What is the risk of uterine rupture with previous classical Caesarean, inverted T or J incisions? (RANZCOG)
classical= 20-90/1000 (2-9%)
T or J= 19/1000 (1.9%)
(vs. 5-7/1000 for lower segment transverse)
(0. 5-0.7%)
Incidence of placenta accreta in 1st, 2nd, 3rd, 4th, 5th 6th or more CS?
1= 0.24% 2= 0.31% 3= 0.57% 4= 2.1% 5= 2.3% 6 or more = 6.7%
Complication rate of elective vs. emergency CS?
elective = 7% emergency = 13.2%
Rates of emCS after for VBAC in in induced, augmented, and spontaneous labour groups?
induced = 33% CS (at least) augmented = 26% CS spontaneous = 18%
Risk of uterine rupture with prostaglandin IOL? R
prostaglandin: 1.4-2.45%
What is the risk of uterine rupture in women augmented with VBAC vs. no augmentation?
augmentation = 1.9%
no augmentation = 0.19%
What is the risk of uterine rupture after foley balloon and ARM in VBAC?
- 3/1000 women (0.8-22.4)
0. 63%
Risk of uterine rupture with any induction method?
12/1000 (9-16)
1.2%
What is the success rate of VBAC after second CS compared to after first? What are the rates of uterine rupture?
71% vs. 77% success
rupture rate 1.6% vs. 0.7%
What is the success rate of VBAC after second CS compared to after first? What are the rates of uterine rupture?
71% vs. 77% success
rupture rate 1.6% vs. 0.7%
What is the rate of mid trimester VBAC uterine rupture with misoprostol induction?
- 04% no CS vs.
0. 28% CS
Contraindications to VBAC?
T or J incisions.
Previous uterine surgery (myomectomy)
Previous uterine rupture
placenta praevia
VBAC success, uterine rupture rate and maternal morbidity after 2 previous CS?
- success 71.1%
- uterine rupture 1.36%
- hysterectomy 56/10,000 (0.6%) vs. 19/10,000 (0.2%),
- transfusion 1.99% vs. 1.21%
What is the risk of maternal death with planned VBAC vs. elective CS?
4/100,000 VBAC (0.004%)
13/100,000 planned CS (0.013%)
What is the risk of transient respiratory morbidity in VBAC vs. elective CS?
2-3% VBAC
4-5% LSCS
Contrast foley IOL and prostaglandin induction for VBAC
a) risk of uterine rupture
b) success
Foley IOL +ARM
a) 0.63%
b) 54-61%
Prostaglandin only
a) 0.7-2.0% (up to 2.45%)
b) 51-63%
Prostaglandin + Oxytocin
a) 1.8% (must be more)
b) 60.2%
Rate of VBAC success with EFW >4kg, no previous vaginal delivery?
Less than 50%, increased uterine rupture rate 3.6%
Risk of hysterectomy when attempting VBAC?
0.5-2/1000 women attempting VBAC
9% if uterine rupture occurs (UKOSS)
Risk of genitourinary injury in women attempting VBAC?
0.8 per 1000 women attempting VBAC
Risk of uterine rupture in term and post term IOL (RANZCOG)
term = 1.5% post-term = 3.2%
Success rate of twin VBAC delivery?
3x small studies
64-76%
no increase in scar rupture or perinatal morbidity
largest study reported
uterine rupture 0.9%
success 45%
Overall major maternal and perinatal morbidity in attempting VBAC?
perinatal = 1/1000 attempting VBAC maternal = 3/1000 attempting VBAC
Risk of perinatal mortality postdates spontaneous VBAC?
1.8/1000
= 0.4 due to uterine rupture
= 1.4 due to postdates
Ranzcog guideline
UKOSS perinatal morbidity and mortality after uterine rupture?
12% mortality
41% admitted nicu median 3 days
6% encephalopathy
Risk of HIE VBAC vs. elective CS?
RCOG=
VBAC= 0.08%. 60% due to uterine rupture.
CS = <0.01%
Risk of delivery prior to 39 weeks?
10%
