Vaginal Birth after Caesarean

Women who have had a previous Caesarean section are often conflicted as to which mode of delivery they want in their next pregnancy. If you have had just the one prior Caesarean section, then the choices are to either have a repeat elective Caesarean section or a vaginal birth after Caesarean (VBAC).

Ordinarily, Caesarean section carries approximately four times the risk associated with a vaginal delivery, but in the event that you have had a previous Caesarean section the risk of a vaginal delivery is similar, if not slightly worse, than a repeat Caesarean section.

Added complications with a VBAC include scar pain and scar rupture which usually means delivery of the baby into your abdomen and not through the vagina. This is obviously a very dangerous situation for both mother and baby, as baby will often pass away and the mother will be in dire straits due to heavy bleeding. With good management, it is seldom the case that the scar rupture is as serious as this.

There was a recent study led by a group of investigators from Adelaide that looked at the safety of VBAC versus Caesarean section. The study was conducted in multiple large centres around Australia and New Zealand. The majority of patients recruited were added to the “patient preference” arm of the trial, where the patients could choose which way they wanted to deliver.

The outcome of the study showed that the risks for both techniques were similar, although the repeat elective Caesarean section was marginally safer. As a result, in my practice I counsel women regarding this trial and the risks and complications that are likely to occur with each type of delivery. Once fully informed, the women and their partners are able to make a choice as to which method they would prefer.

When undertaking a vaginal birth after Caesarean section the main risk that we worry about is the risk of rupture of the uterine scar. Rupture can be a minor problem with pain and some increase in bleeding and often signs of fetal distress on a CTG (fetal heart trace), or it could be a catastrophic event where the baby will pass away and the mother’s life is at risk due to heavy bleeding. Scar ruptures more commonly occur towards the milder side of the scale. To gain some perspective, the risk of rupture of a uterine scar during a pregnancy where there is no labour involved is approximately 1:1000. If labour occurs the risk of rupture of the uterine scar is approximately 1:200.

If you have had more than one Caesarean section or you have had a classical Caesarean section (the uterine scar is an up and down scar), then your risk of rupturing that scar in labour is approximately 1:25. I feel that a 1:25 risk is unacceptable and I do not offer VBAC for women who have had more than one Caesarean section. I am happy to manage labour and delivery in women who have only had one previous Caesarean section.