An audit on the outcome of vaginal Birth after Caesarean Section (VBAC) in a Sri Lankan tertiary care setting and factors associated with failure

Abstract

Introduction: Caesarean section is a major surgical operation and its rate is on the rise in Sri Lanka as well as in the world. It is recommended to lower the Caesarean section rate due to the risk of potential complications and burden on the health care system. Previous Caesarean is a common indication for planned Caesarean section and vaginal birth after Caesarean section (VBAC) is considered a safe alternative for many women. This audit study was aimed at determining the success rate of VBAC in a local setting and to identify the factors that are associated with failure in this study population. Method: An audit study was carried out in two obstetric units if South Colombo Teaching hospital, Kalubowila and De Soysa hospital for women, Colombo 8 to assess the success rate among women who underwent VBAC. The unit policies included patient choice for decision to undergo VBAC and non-usage of medication either for induction or augmentation of labour. The audit standards were set as a VBAC success rate of 72% (RCOG Green-top guidelines) and a low APGAR (<7) in less than 2% of neonates (set by clinical experience). The demographic and past obstetric factors were compared between groups to determine significant associations. Results: A total of 161 women (37.8% of those with a previous one Caesarean) had opted to undergo VBAC during the study period. It was successful in 69.6% of the total study sample and 84.6% who has had a previous vaginal delivery. Low APGAR scores at 5 minutes was observed in two neonates (1.2%) and both these were in the group with a successful VBAC. The factors associated with failed VBAC in this study population included not having had a previous vaginal delivery (Odds ratio 2.99), poor progress of labour being the indication for previous section (OR 2.32), a cervical dilatation of <2cm at onset of labour (OR 4.43), malpositions in early labour (OR 12.24), and a birth weight of more than 3000g (OR 2.11). Other preciously described factors such as a high BMI and inter-delivery interval failed to show a significant association in this study group. Discussion and recommendations: The take up rate of VBAC in our study population seems to be low. However, the study did not study the reasons contributing to this low rate hence no recommendations can be made. The success rate of VBAC on our group (69%) was very close to the set standards (72%) and the rate of low APGAR at 5 minutes was 1.2% and was achieving the set standard. These figures along with the factors identified to be associated with the failure at VBAC should be used for patient counseling in our local setting. Other units also should carry out such audit projects to find out the success rate of VBAC in their respective units. More in-depth studies should be carried out to find causes for low rate of undergoing VBAC and to determine effective ways to improve it.