Predicting Successful Trial of Labor After Cesarean Delivery: Evaluation of Two Scoring Systems.

ABSTRACT

BACKGROUND: Attempting vaginal birth after cesarean section (VBAC) places women at an increased risk of complications. Trial of labor after cesarean (TOLAC) calculators aim to predict the chance of successful vaginal birth after cesarean (VBAC) based on the patient's preexisting demographic and clinical factors. OBJECTIVE: To assess the rate of successful TOLAC using two calculators FLAMM and the Grobman calculator, and to compare the performance of the two calculators in the successful prediction of VBAC. METHODS: Prospective cohort study in subjects with previous one caesarean section using well-defined inclusion and exclusion criteria. RESULTS: A total of 280 subjects with previous one cesarean section were enrolled. One hundred thirty-nine subjects consented for TOLAC, 90 (67%) underwent successful trial of vaginal birth, and 49 (32.8) required cesarean section. Cervical dilatation (p < 0.0001) and effacement (p < 0.0001), and any prior vaginal delivery (p < 0.02) were significantly associated with a successful outcome. At a cutoff score of 5, the sensitivity of the FLAMM score was 72% and specificity was 76%. For the Grobman calculator, the best sensitivity (69%) and specificity (67%) were seen at a cutoff score of 85%. CONCLUSION: Both prediction models, the FLAMM and the "close to delivery" nomogram, recommended by Grobman et al. are easy to use and could successfully estimate the chances of vaginal birth in previous caesarean, in this small cohort. The decision for women opting for TOLAC can be individualized, and patient-specific chances of success can be predicted by the use of these prediction models.