VBAC Flashcards
What is the chance of a successful VBAC?
60-80%
RANZCOG Guideline
What are factors that favour a successful VBAC?
Previous safe vaginal birth
Previous successful VBAC
Spontaneous onset of labour
Uncomplicated pregnancy without other risk factors
What are factors that reduce the likelihood of a successful VBAC?
Previous CS for dystocia IOL Co-existing fetal, placental or maternal conditions Maternal BMI > 30 Fetal macrosomia >4kg AMA Short stature More than one previous CS Risk factors associated with an increased risk of uterine rupture
What is the chance of a successful VBAC in a woman that has had a previous vaginal birth?
87-91%
What is the incidence of scar rupture in a patient undergoing VBAC?
5-7:1000
RANZCOG guideline
What is the risk of uterine rupture associated with previous classical CS?
20-90:1000
What is the risk of uterine rupture associated with previous T or J incisions?
19:1000
What are the symptoms and signs of uterine rupture?
Abnormal CTG (present n 55-87% cases)
Severe abdominal pain especially persisting between contractions
Chest pain or shoulder tip pain
Sudden onset of shortness of breath
Acute onset of scar tenderness
Abnormal vaginal bleeding or haematuria
Cessation of previously efficient uterine activity
Maternal tachycardia, hypotension or shock
Loss of station of the presenting part
What are the benefits of a successful VBAC?
Less maternal morbidity for index pregnancy and future pregnancies
Avoidance of major surgery and multiple CS in future pregnancies
Earlier mobilisation and discharge from hospital
Patient gratification in achieving vaginal birth if this is desired
What are the risks of a VBAC?
Increased perinatal loss compared with ERCS at 39/40 (1.8 per 1000 pregnancies)
HIE risk (0.7 per 1000)
- related to labour and vaginal birth and to scar rupture
Increase morbidity of EmCS compared to ElCS if unsuccessful VBAC
Pelvic floor trauma
What are the benefits of an ERCS?
Avoid late stillbirth (after 39 weeks)
Reduced perinatal mortality and morbidity (especially HIE) related to labour, delivery and scar rupture
Reduced maternal risks associated when compared with EmCS
Avoidance of trauma to the maternal pelvic floor
Convenience of planned date for birth
What are the risks of ERCS?
Surgical morbidity and complications Both with index pregnancy and further pregnancies (including praevia, accreta)
Increased risk of neonatal respiratory morbidity - TTN, RDS, pulmonary HTN
Lower rates of initiating breastfeeding
With attempted VBAC, what is the risk of perinatal death?
0.4-0.7/1000
A further 1.4 (to total 1.8) may be expected to have an antenatal, intrapartum or neonatal death after 39 weeks gestation
It is appropriate that this increase in perinatal mortality be acknowledged
- even though mostly not a direct consequence of uterine rupture
With attempted VBAC, what is the risk of maternal death?
0.02/1000
With attempted VBAC, what is the risk of hysterectomy?
0.5-2/1000
With attempted VBAC, what is the risk of HIE?
0.4/1000
As the number of CS increases, there is a statistically significant increase in the risk of…
Severe haemorrhage (requiring >4u RBC)
Hysterectomy
Bladder injury
Bowel injury
And placenta praevia + accreta
What is the increase in the risk of uterine rupture with a pregnancy interval less than 18-24 months, following CS
2-3 x increase
With BMI > 40, what is the risk of uterine rupture / dehiscence
2%
Prospective observational study of >14,000 patients
How often should a woman having a TOLAC have VEs?
Q4h
After 7cm, q2 hourly to detect a secondary arrest of labour
What are the rates of
- successful vaginal birth
- uterine rupture
In V2BACs compared to V1BAC
- successful vaginal birth: 71% vs 77%
- uterine rupture: 1.6% vs 0.7%
BUT multivariate analysis of NICHD showed no sig diff rates in rupture
RCOG states that if a patient has been fully informed by a Consultant Obstetrician, they may be suitable
How does epidural affect the success rate of VBAC?
Success rate:
- With epidural: 70%
- Without epidural: 50%
What are the contraindications to VBAC?
- Previous uterine rupture
- Previous classical/vertical uterine incision
- Any contraindication to vaginal delivery: praevia, footling breech etc.
