Vaginal birth after Caesarian Section (VBAC), can be achieved safely in the appropriate setting, with the appropriate patient in about 75% of women who have previously had a single caesarean delivery.
The predominant risk of VBAC is the small but real risk of uterine rupture at some point during the labour or delivery. The reported risk is about 1 in 300 VBAC attempts. Scar rupture can be a serious complication if it occurs, with a 10% chance of still birth, and a 10% chance of the mother needing a hysterectomy due to heavy uncontrollable bleeding.
Reducing the risk of scar rupture is done by careful patient selection and pro-active management of the labour.
Women who are unsuitable for an attempt at VBAC include:
- Women who have had 2 or more Caesarian sections.
- Women who have had a prior “Classical” or T-shaped incision on their uterus in prior Caesarian Sections.
- Prior removal of a uterine fibroid .
- Previous rupture of the uterus.
- Women who need induction of labour, but have a cervix which is unfavourable for induction.
- The baby is presenting breech, or lying in a transverse position (i.e. side on).
- The baby appears to be too big to pass through the birth canal, or if prior babies which have been quite small have become quite stuck in the birth canal in prior labours.
The management of the labour for a VBAC includes the following (to minimise risk):
- An IV is placed in the hand for access into a vein and blood is sent for Group and Hold in case of any bleeding.
- The baby’s heart beat is monitored constantly via CTG tracing for the whole labour.
- Regular checks to ensure progress in labour and exclude signs of obstruction.
Two of the common reasons for a Caesarian Section to be performed are concerns about the baby’s heartbeat and / or the cervix failing to dilate.