OptiBIRTH: a cluster randomised trial of a complex intervention to increase vaginal birth after caesarean section

Abstract Background Despite evidence supporting the safety of vaginal birth after caesarean section (VBAC), rates are low in many countries. Methods OptiBIRTH investigated the effects of a woman-centred intervention designed to increase VBAC rates through an unblinded cluster randomised trial in 15 maternity units with VBAC rates 24 weeks gestation occurred in the intervention group (0.34%) and 4/782 in the control group (0.51%), and two uterine ruptures (one per group), a rate of 1:1000. Conclusions Changing clinical practice takes time. As elective repeat CS is the most common reason for CS in multiparous women, interventions that are feasible and safe and that have been shown to lead to decreasing repeat CS, should be promoted. Continued research to refine the best way of promoting VBAC is essential. This may best be done using an implementation science approach that can modify evidence-based interventions in response to changing clinical circumstances. Trial registration The OptiBIRTH trial was registered on 3/4/2013. Trial registration number ISRCTN10612254 .