Vaginal Birth after C-section

Question 1

What percentage of women with a previous c-section who labour achieve vaginal delivery

Answer 1

Up to 72-75%

Question 2

When is planned VBAC appropriate

Answer 2

May be offered to the majority of women with a singleton pregnancy of cephalic presentation at 37+0 weeks or beyond who have had a single previous lower segment caesarean delivery, with or without a history of previous vaginal birth

Question 3

Contraindications to VBAC

Answer 3

• Women with previous uterine rupture or a classical uterine scar
• Other absolute contra-indications to vagina birth that apply irrespective of previous c-section (major placenta praevia )
• Previous uterine surgery (e.g myomectomy- particularly where the uterine cavity has been breached)
• Women who have had two or more prior lower segment caesarean deliveries may be offered VBAC after counselling by a senior obstetrician
• This should include the risk of uterine rupture and maternal morbidity, and the individual likelihood of successful VBAC
• Labour should be conducted in a centre with suitable expertise and recourse to immediate surgical delivery
• Factors which increase the risk of uterine rupture: short inter-delivery interval (less than 12 months since last delivery), post-date pregnancy, maternal age of 40 years or more, obesity, lower prelabour Bishop score, macrosomia and decreased ultrasonographic lower segment myometrial thickness

Question 4

What is the best predictor for a successful VBAC. What are some other predictors of success

Answer 4

Previous successful VBAC- success ratio of 85-90%. Previous vaginal delivery is also independently associated with a reduced risk of uterine rupture.
* In addition: Greater maternal height, maternal age less than 40 years, BMI less than 30, gestation of less than 40 weeks and infant birthweight less than 4 kg (or similar/lower birthweight than index caesarean delivery106) are associated with an increased likelihood of successful VBAC

Question 5

What are some risk and benefits of a planned VBAC vs ECRS from 39+0 weeks gestation

Answer 5

• Successful VBAC has the fewest complications and therefore the chance of VBAC success or failure is an important consideration when choosing mode of delivery
• The greatest risk of adverse outcomes occurs in a trial of VBAC resulting in emergency c-section
• Planned VBAC is associated with an approximately 1 in 200 (0.5%) risk of uterine rupture
• The absolute risk of birth-related perinatal death is extremely low and comparable to the risk for nulliparous women in labour
• ERCS (elective repeat caesarean section) is associated with a small increased risk of placenta praevia and/or accreta in future pregnancies and of pelvic adhesions complicating any future abdominopelvic surgery
• The risk of perinatal death with ERCS is extremely low, but there is a small increase in neonatal respiratory morbidity when ERCS is performed before 39+0 weeks of gestation.
  o Risk of ARD can be reduced with a preoperative course of antenatal corticosteroids
• Bear in mind option for sterilisation- should be included in counselling around 2 weeks prior to operation
• Slightly increased risk of stillbirth with VBAC (additional 10 per 10000)

Question 6

Intrapartum management of VBAC

Answer 6

All women should receive:
* Supportive 1-to-1 care
* IV access withgroup and save + 2 units crossmatched
* Continuous CTG
* Regular VE for progress

Epidural analgesia is not contraindicated in a planned VBAC, although an increasing requirement
for pain relief in labour should raise awareness of the possibility of an impending uterine rupture. Associated symptoms include:
* Abnormal CTG (66-76%)
* Severe abdominal pain, especially between contractions
* Scar tenderness and abnormal vaginal bleeding (or haematuria)
* Cessation of previously efficient uterine activity and loss of station
* Maternal tachycardia, hypotension, fainting or shock

Women should be informed of the two- to three-fold increased risk of uterine rupture and around 1.5-fold increased risk of caesarean delivery in induced and/or augmented labour compared with spontaneous VBAC labour- should use mechanical methods rather than prostaglandins

Question 7

Intrapartum management of ERCS

Answer 7

• ERCS delivery should be conducted after 39+0 weeks of gestation.
• Antibiotics should be administered before making the skin incision in women undergoing ERCS.
• All women undergoing ERCS should receive thromboprophylaxis according to existing RCOG guidelines.
• Early recognition of placenta praevia, adopting a multidisciplinary approach and informed consent are important considerations in the management of women with placenta praevia and previous caesarean delivery