Q: What should I know if I want to have VBAC (vaginal birth after caesarean) for my second baby? 

Answered by: Dr Tan Niap Hong, Consultant Obstetrician & Gynaecologist, and Clinical Head of Obstetrics & Gynaecology Service at Prince Court Medical Centre

In general, VBAC has a success rate of about 70% but carries a small risk of uterine rupture (less than a 1% risk). It is important to find out the type of the previous uterine incision because a low transverse uterine scar runs a lower risk of rupture during labour. A high vertical (classical) incision or a previous fibroid removal incision that traverses the entire uterine wall thickness are considered contra-indications for VBAC. 

VBAC is also not advisable if the previous Caesarean section was done for cephalo-pelvic disproportion (when the baby’s head is too large to allow it through the mother’s pelvis). It is also important to understand that the risks of VBAC increases and the likelihood of success decreases in the presence of advanced maternal age, maternal obesity, large baby, short interval of less than 18 months from the previous Caesarean, and pregnancy complications such as preeclampsia.