Simple, validated vaginal birth after cesarean delivery prediction model for use at the time of admission.
OBJECTIVE
To create a simple tool for predicting the likelihood of successful trial of labor after cesarean delivery (TOLAC) during the pregnancy after a primary cesarean delivery using variables available at the time of admission.


METHODS
Data for all deliveries at 14 regional hospitals over an 8-year period were reviewed. Women with one cesarean delivery and one subsequent delivery were included. Variables associated with successful VBAC were identified using multivariable logistic regression. Points were assigned to these characteristics, with weighting based on the coefficients in the regression model to calculate an integer VBAC score. The VBAC score was correlated with TOLAC success rate and was externally validated in an independent cohort using a logistic regression model.


RESULTS
A total of 5,445 women met inclusion criteria. Of those women, 1,170 (21.5%) underwent TOLAC. Of the women who underwent trial of labor, 938 (80%) had a successful VBAC. A VBAC score was generated based on the Bishop score (cervical examination) at the time of admission, with points added for history of vaginal birth, age younger than 35 years, absence of recurrent indication, and body mass index less than 30. Women with a VBAC score less than 10 had a likelihood of TOLAC success less than 50%. Women with a VBAC score more than 16 had a TOLAC success rate more than 85%. The model performed well in an independent cohort with an area under the curve of 0.80 (95% confidence interval 0.76-0.84).


CONCLUSIONS
Prediction of TOLAC success at the time of admission is highly dependent on the initial cervical examination. This simple VBAC score can be utilized when counseling women considering TOLAC.


METHODS
II.
Department of Obstetrics and Gynecology and Study Design and Biostatistics Center, University of Utah, Salt Lake City, Utah, USA. torri.metz@dhha.org
Torri D
TD
Metz
Gregory J
GJ
Stoddard
Erick
E
Henry
Marc
M
Jackson
Calla
C
Holmgren
Sean
S
Esplin
D000328:Adult; D005260:Female; D005544:Forecasting; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D010343:Patient Admission; D011237:Predictive Value of Tests; D011247:Pregnancy; D012189:Retrospective Studies; D014219:Trial of Labor; D016064:Vaginal Birth after Cesarean; D055815:Young Adult