Background: Previous studies assessing the safety of vaginal birth after caesarean section (VBAC) have compared VBAC to elective repeat caesarean section (ERCS), despite the fact that the risks posed by each are considerably different. Explaining the complications of VBAC in a way that is meaningful to women can be challenging, and thus a comparison to a similar group of women who have also not undergone previous vaginal delivery may be a more relevant comparison.
Research Question: When counselling women undergoing planned VBAC, should a comparison of outcomes be made to women undergoing ERCS, or is a comparison to other nulliparous women undergoing vaginal birth a more valid comparison in terms of risk outcomes?
Participants And Methods: A retrospective cohort study was undertaken comprising a consecutive cohort of 21,389 women who delivered, stratified by Robson's criteria into Robson groups 1-5.