Validation of a Predictive Model of Vaginal Birth after Caesarean Section in Pakistani Women

To determine the frequency of successful trials of vaginal birth after Caesarean section (VBAC) using the Flamm and Geiger model.

Observational study. Place and Duration of the Study: Obstetrics and Gynaecology Unit II of Dr. Ruth K.M. Pfau Civil Hospital, Karachi, Pakistan, from August 2022 to January 2023.

Women with singleton pregnancy having cephalic presentation, previous one lower segment caesarean section (LSCS), and without any contraindication for vaginal delivery were included. Women bearing foetus having estimated weight >3.5kg, morbid obesity, multiple pregnancies, non-cephalic presentation, placenta praevia, abruptio placentae, uncontrolled maternal comorbidities, or had previous two or more Caesarean sections were excluded. Flamm and Geiger score was applied to record observations of successful and unsuccessful trials. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the score were calculated by ROC curve, along with its area under the curve (AUC) and Youden's index curve, with 95% confidence interval.

This study included 258 participants. Successful vaginal delivery was possible in 125 (48.4%) participants, whereas 133 (51.6%) underwent emergency Caesarean section. Cervical dilatation and effacement were the main factors assessing the success. The Flamm and Geiger score of >5 had an area under the curve of 0.813 (0.762-0.864). The score's sensitivity was 75% (67-82%), specificity 76% (68-82%), and PPV of 75% with an accuracy of 76%.

The Flamm and Geiger score of >5 demonstrated high sensitivity, specificity, PPV, and accuracy in predicting later successful vaginal birth. It is recommended as a promising and valuable tool for assessing VBAC's success in low-resource countries.

Vaginal birth after caesarean, Flamm and Geiger Model, Indication of caesarean, trial of labour after caesarean, VBAC risk scoring criteria.