Grobman et al reported a model for predicting vaginal birth after cesarean delivery (VBAC) that does not include race or ethnicity. The authors are from multiple institutions in the United States participating in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.
Patient selection: woman in labor with history of cesarean delivery
Parameters:
(1) maternal age in years
(2) maternal weight at delivery in kg
(3) maternal height in cm
(4) indication for previous cesarean delivery
(5) past history of deliveries
(6) previous VBAC
(7) hypertensive disorder of pregnancy
(8) fetal station
(9) gestational age at admission in weeks
(10) cervical dilation in cm
(11) cervical effacement in percent
|
Parameter
|
Finding
|
Points
|
|
maternal age in years
|
|
-0.031 * (age)
|
|
maternal weight in kg
|
|
- 0.016 * (weight)
|
|
maternal height in kg
|
|
0.054 * (height)
|
|
indication for cesarean
|
arrest disorder
|
-0.621
|
|
|
other
|
0
|
|
past history of deliveries
|
previous vaginal delivery only before previous cesarean delivery
|
0.885
|
|
|
other
|
0
|
|
previous VBAC
|
no
|
0
|
|
|
yes
|
1.733
|
|
hypertensive disorder
|
no
|
0
|
|
|
yes
|
-0.563
|
|
fetal station
|
-3
|
0.003
|
|
|
-2
|
0.231
|
|
|
-1
|
0.524
|
|
|
0
|
0.85
|
|
|
+1 or greater
|
1.330
|
|
gestational age in weeks
|
|
-0.14 * (weeks)
|
|
cervical dilation in cm
|
|
0.119 * (cm)
|
|
cervical effacement
|
|
0.006 * (effacement)
|
value of X =
= SUM(points for all of the parameters) - 1.061
probability of VBAC =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve is 0.78.
