Factors associated with success of vaginal birth after one caesarean section (VBAC) at three teaching hospitals in Addis Ababa, Ethiopia: a case control study.

Background: Vaginal delivery after previous one cesarean section for a non recurring indication has been described by several authors as safe and having a success rate of 60-80%. Hence many centers are offering VBAC for candidates leaving the century old dictum of once cesarean always cesarean. But predicting success of VBAC after trial of labor (TOL) is still a difficult task due to the lack of a validated prediction tool. Studies on predictors of success are few and most of them conducted in developed countries and difficult to generalize. Therefore assessing factors associated with successful VBAC is very important to for counseling mothers while offering VBAC. The aim of this study was to assess factors associated with successful VBAC in three teaching Hospitals in Addis Ababa Ethiopia.

Methods: A case control study was conducted to compare the factors associated with successful VBAC in teaching hospitals in Addis Ababa in one year period. The cases were those successfully delivered vaginally and the controls were those with failed VBAC and delivered by caesarean section. The sample size of the cases was 101vaginal deliveries and the controls were 103 failed VBAC patients which made the case to control ratio of 1:1.

Result: In this study independent factors determining successful VBAC were, history of successful VBAC in the past, rupture of membrane at admission, and cervical dilatation of more than 3cm at admission. Presence of meconium, malposition and history of stillbirth were associated with failed VBAC. Factors like maternal age, past caesarean indications, inter delivery interval, and birth weight were not found to be significant determinants of success. The most common reason for repeat cesarean section for after trial of labor was labour dysfunction because of absence of a policy for augmentation on a scarred uterus in these hospitals.

Conclusion: It is possible to prepare a decision tool on the success of VBAC by taking important past and present obstetric and reproductive performance history as predictor.