Metz Torri D, Allshouse Amanda A, Faucett Allison M, Grobman William A
Departments of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, and Denver Health Medical Center, Denver, and the Department of Biostatistics and Informatics, Colorado School of Public Health at the University of Colorado Denver, Denver, Colorado; and Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
Obstet Gynecol. 2015 Apr;125(4):948-952. doi: 10.1097/AOG.0000000000000744.
To evaluate whether an existing vaginal birth after cesarean delivery (VBAC) prediction model validated for women with one prior cesarean delivery also accurately predicts the likelihood of VBAC in women with two prior cesarean deliveries.
We performed a secondary analysis of all women attempting trial of labor after cesarean delivery (TOLAC) with a term singleton pregnancy and two prior cesarean deliveries in the Maternal-Fetal Medicine Units Network (MFMU) Cesarean Registry. Probability of VBAC was calculated for each participant using the MFMU VBAC prediction model. Women were considered to have a recurring indication for cesarean delivery if the indication for either their first or second cesarean delivery was arrest of dilation or descent. A receiver operating characteristic curve was used to assess the classification ability of the model and the predicted likelihood of VBAC success was compared with the actual likelihood using a calibration curve.
Among 369 women with two prior cesarean deliveries undergoing TOLAC, the actual VBAC rate was 66% (95% confidence interval [CI] 61-71). The mean predicted probability of VBAC was higher among women with a successful TOLAC than those with a failed TOLAC (75% compared with 59%, P<.001). The area under the receiver operating characteristic curve for women with two prior cesarean deliveries was 0.74 (95% CI 0.69-0.80). Within deciles of predicted probability greater than 30%, predicted probabilities were similar to and contained actual probabilities within the 95% CI.
The estimates of VBAC success based on the MFMU prediction model are similar to the actual rates observed among women with two prior cesarean deliveries.
评估一个已针对有一次剖宫产史的女性验证过的现有剖宫产术后阴道分娩（VBAC）预测模型，是否也能准确预测有两次剖宫产史的女性发生VBAC的可能性。
我们对母胎医学单位网络（MFMU）剖宫产登记处中所有有两次剖宫产史且单胎足月妊娠并尝试剖宫产术后阴道试产（TOLAC）的女性进行了二次分析。使用MFMU VBAC预测模型为每位参与者计算VBAC的概率。如果首次或第二次剖宫产的指征是产程停滞或胎头下降停滞，则认为这些女性有再次剖宫产的指征。使用受试者工作特征曲线评估模型的分类能力，并使用校准曲线将预测的VBAC成功可能性与实际可能性进行比较。
在369例有两次剖宫产史且进行TOLAC的女性中，实际VBAC率为66%（95%置信区间[CI] 61 - 71）。TOLAC成功的女性中VBAC的平均预测概率高于TOLAC失败的女性（分别为75%和59%，P<0.001）。有两次剖宫产史女性的受试者工作特征曲线下面积为0.74（95% CI 0.69 - 0.80）。在预测概率大于30%的十分位数范围内，预测概率与实际概率相似，且实际概率包含在95% CI内。
基于MFMU预测模型的VBAC成功估计值与有两次剖宫产史女性中观察到的实际发生率相似。
