Bhide et al developed a model for predicting vaginal birth after cesarean delivery. The authors are from St. George’s University in London.
Patient selection: pregnant woman with history of cesarean delivery
Exclusions: multiple pregnancies, multiple previous cesarean deliveries, preterm delivery
Parameters:
(1) body mass index of the mother in kg per square meter
(2) ethnic origin
(3) smoking status
(4) previous cesarean for failure to progress
(5) any medical condition complicating pregnancy
|
Parameter |
Finding |
Points |
|
body mass index |
|
0.01 * BMI |
|
ethnic origin |
Whte European |
0 |
|
|
Asian |
0.466 |
|
|
African |
0.587 |
|
|
other |
0.333 |
|
smoking status |
smoker |
-1.62 |
|
|
nonsmoker |
-0.81 |
|
previous cesearean |
for failure to progress |
1.854 |
|
|
other |
0 |
|
medical condition |
none |
0 |
|
|
any |
0.126 |
where:
• The handling of smoking status is not described. The only system that gets values similar to the values in Table 4 is that smoking status is 1 if nosmoker and 2 if smoker, multiplied by the beta -0.81.
X =
= SUM(points for all 5 parameters) – 1.171
probability of failed attempt =
= 1 / (1 + EXP((-1) * X))
probability of successful VBAC =
= 1 – (probability of failure)
Specialty: Obstetrics & Gynecology
