Background. External validation of a vaginal birth after cesarean delivery (VBAC) prediction model is important before implementation in other settings. The primary aim of this study is to validate the Grobman prenatal VBAC calculator in the Ethiopian setting. Secondarily, the study was aimed at developing and comparing a new VBAC model that includes both the prenatal and intrapartum variables. Methods. A cross-sectional survey was conducted, complemented by a medical chart review of 268 women admitted at three teaching hospitals of Addis Ababa University and who underwent a trial of labor after one prior cesarean birth. Maternal age, prepregnancy BMI, prior vaginal delivery, prior VBAC, and prior cesarean delivery indication type were included in the Grobman model. Observed delivery outcomes were recorded and then compared with the outcomes predicted by the calculator. We assessed the predictive abilities of the Grobman model and the new model using a receiver operating characteristic (ROC) curve. Multivariate logistic regression analysis was conducted to identify variables associated with successful VBAC. Results. Out of the 268 participants, 186 (69.4%) (95% CI 57.5-81.3) had successful VBAC. The area under the ROC curve (AUC) of the Grobman model was 0.75 (95% CI 0.69-0.81). Notably, the novel model including both the prenatal and intrapartum variables had a better predictive value than the original model, with an AUC of 0.87 (95% CI 0.81-0.93). Prior VBAC, prepregnancy BMI, fetal membrane status, and fetal station at admission were predictors of VBAC in the newly developed logistic regression model. Conclusions. The success rate of VBAC was similar to other sub-Saharan African countries. The Grobman model performed adequately in the study setting; however, the model including both the prenatal and intrapartum variables was more predictive. Thus, intrapartum predictors used in the new model should be considered during intrapartum counseling.

中文翻译：

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亚的斯亚贝巴大学教学医院剖宫产后阴道分娩预测模型的验证：一项横断面研究

背景。在其他环境中实施之前，对剖宫产后阴道分娩 (VBAC) 预测模型的外部验证很重要。本研究的主要目的是在埃塞俄比亚环境中验证 Grobman 产前 VBAC 计算器。其次，该研究旨在开发和比较一种新的 VBAC 模型，该模型包括产前和产时变量。方法. 进行了一项横断面调查，并对在亚的斯亚贝巴大学三所教学医院收治的 268 名妇女进行了医学图表审查，这些妇女在一次剖宫产后接受了分娩试验。Grobman 模型包括产妇年龄、孕前 BMI、既往阴道分娩、既往 VBAC 和既往剖宫产指征类型。记录观察到的分娩结果，然后与计算器预测的结果进行比较。我们使用受试者工作特征 (ROC) 曲线评估了 Grobman 模型和新模型的预测能力。进行多变量逻辑回归分析以确定与成功的 VBAC 相关的变量。结果. 在 268 名参与者中，186 名 (69.4%) (95% CI 57.5-81.3) 成功完成了 VBAC。Grobman 模型的 ROC 曲线下面积 (AUC) 为 0.75 (95% CI 0.69-0.81)。值得注意的是，包含产前和产时变量的新模型比原始模型具有更好的预测价值，AUC 为 0.87 (95% CI 0.81-0.93)。在新开发的逻辑回归模型中，先前的 VBAC、孕前 BMI、胎膜状态和入院时的胎位是 VBAC 的预测因素。结论. VBAC 的成功率与其他撒哈拉以南非洲国家相似。Grobman 模型在研究环境中表现良好；然而，包含产前和产时变量的模型更具预测性。因此，在产时咨询期间应考虑新模型中使用的产时预测因子。