VBAC Success Prediction Score (Flamm / Grobman)

Predicts probability of successful vaginal birth after cesarean (VBAC) using validated models.

Prediction model * Flamm is used at admission; Grobman antenatal is used in early pregnancy.

Maternal age *

years

Age at delivery.

BMI *

kg/m2

Pre-pregnancy or booking BMI.

Prior vaginal delivery * History of vaginal birth.

Recurring indication for prior C-section e.g., failure to progress/CPD (recurrent) vs. breech/fetal distress (non-recurrent).

Cervical dilation at admission (Flamm/Grobman intrapartum)

If admission/intrapartum model selected.

Cervical effacement at admission (Flamm/Grobman intrapartum) If admission/intrapartum model selected.

Ethnicity (Grobman antenatal only) 2021 Grobman model omits race.

Hypertensive disorder of pregnancy (Grobman intrapartum) Preeclampsia, gestational hypertension, or chronic hypertension.

Labor induction (Grobman intrapartum) Planned or active induction.

Enter values and click Calculate to see results

Vaginal birth after cesarean delivery: an admission scoring system (Flamm). Obstetrics & Gynecology (1997). Link
Development of a nomogram for prediction of vaginal birth after cesarean delivery (Grobman). Obstetrics & Gynecology (2007). Link
Models for predicting vaginal birth after cesarean section - systematic review. BMC Pregnancy and Childbirth (2019). Link