Vaginal Birth after Caesarean

Delivery Obstetrics 

Some women, who have previously had one caesarean section, consider having a natural birth in a subsequent pregnancy.

The benefits of having a VBAC (Vaginal Birth after Caesarean) are fairly straightforward – you have no abdominal surgery or wound to recover from, you can leave the hospital sooner and do not have to undertake the risks associated with caesarean delivery.

As long as there are no reasons that a caesarean has be done again and you have had only one previous caesarean, a VBAC is an option. I do not recommend VBAC in women who have had 2 or more previous caesareans.

The chances of having a successful VBAC depend on a number of factors:

Previous vaginal birth 90% (9 in 10)
No previous vaginal birth, in the presence of spontaneous labour, and previous caesarean was for ….
Non recurrent cause, e.g. breech 85% (8.5 in 10)
CTG concerns ‘fetal distress’ 75% (7.5 in 10)
Failure to progress 60% (6 in 10)
Success is reduced by
Induction of labour 10% to 15%
Fetus over 4kg 10% to 15%
Gestational diabetes 10%
Obesity 15% if BMI >30 vs <25
Maternal age > 35 – 40 not well quantified
Gestational age > 40 weeks not well quantified

The major risk of a VBAC is uterine rupture. This is where the scar on the womb (not the scar on the skin) breaks open during labour. This can lead to internal haemorrhage and would need an emergency caesarean section. The risk of this is:

Overall risk of clinical uterine rupture 0.5% (1 in 200)
With syntocinon induction or augmentation 1.0% (1 in 100)
Consequences of rupture for the baby
Risk of death 0.05% to 0.1% (1 in 1000-2000)
Risk of permanent brain injury 0.05% to 0.1% (1 in 1000-2000)
Consequences of rupture for the mother
  • Emergency caesarean section
  • Possible hysterectomy
  • Possible bladder injury
  • Blood transfusion

 There are risks of elective caesarean section as well:

Baby having breathing problems 3.5% with elective (1 in 29)
1.0% with emergency (1 in 100)
0.5% with vaginal birth (1 in 200)
Stillbirth at Term 0.1% with previous CS (1 in 1000)
0.05% with previous VB (1 in 2000)
Placenta praevia 1.0% with 3 previous CS (1 in 100)
0.3% with no previous CS
Placenta accreta 0.31% with 2nd CS (1 in 323)
2.13% with 4th CS, 6.74% with 6th CS
The risks of the mother being unwell, and requiring treatment such as transfusion are …
Successful VBAC
Elective CS
Emergency CS / failed VBAC
2.4% (1 in 42)
3.6% (1 in 28)
14.1% (1 in 7)

The decision to attempt a vaginal birth after a caesarean section is often quite emotional and some ladies feel very strongly about VBAC or having an elective caesarean. A VBAC can be attempted after a discussion has been had about whether or not you would be a suitable candidate.

If you do not have any conditions such require caesarean delivery, have only had one previous lower transverse uterine incision, have no other uterine scars, have never had a uterine rupture and do not have pelvic problems which prevent vaginal delivery, then you may want to consider VBAC.

We recommend that you have an IV cannula in your hand during labour and have the baby continuously monitored during the labour as a precaution.

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