🤰 VBAC Success Score (Flamm Model)
UseWhen to use: counselling for TOLAC when admission cervical exam and obstetric history are known.
StrataHigher scores tracked higher VBAC success in the derivation cohort; low scores are not absolute failure predi…
LimitsWhen not to use: classical/T incision, placenta previa, or other abso… · Pitfall: treating cohort % as an individual guarantee or skipping rup… · Local resources for emergency cesarean matter as much as the score.
SourceACOG / SMFM TOLAC guidance (tool-page edition); China obstetrics TOLAC consensus on zh when cited
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
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Methodology · worked example, guidelines & full notes
Public Flamm points 0–10.
When to use
When to use: counselling for TOLAC when admission cervical exam and obstetric history are known.
How it works
Age <40 (2) + vaginal-birth history (0/1/2/4) + non-FTP indication (1) + effacement (<25%=0, 25–75%=1, >75%=2) + dilation ≥4 cm (1). Cohort success bands from Flamm 1997.
Key points
- Public Flamm points 0–10.
- Low score ≠ mandatory repeat CS.
- Next: local TOLAC pathway; Grobman models are separate calculators.
References
- [Guideline / primary source]ACOG / SMFM TOLAC guidance (tool-page edition); China obstetrics TOLAC consensus on zh when cited
- Flamm BL, Geiger AM. Obstet Gynecol 1997 (VBAC scoring system)
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Maternal age < 40 years | No (0) |
|---|---|
| Vaginal birth history | Vaginal birth before cesarean only (1) |
| Prior cesarean for reason other than failure to progress | No — failure to progress / CPD (0) |
| Cervical effacement at admission | 25–75% (1) |
| Cervical dilation ≥ 4 cm at admission | No (0) |
→Flamm VBAC2pts
- Cohort success band：~49% success (score 0–2)
- Range：0–10 points (Flamm 1997)
| Maternal age < 40 years | No (0) |
|---|---|
| Vaginal birth history | No previous vaginal birth (0) |
| Prior cesarean for reason other than failure to progress | No — failure to progress / CPD (0) |
| Cervical effacement at admission | < 25% (0) |
| Cervical dilation ≥ 4 cm at admission | No (0) |
→Flamm VBAC0pts
- Cohort success band：~49% success (score 0–2)
- Range：0–10 points (Flamm 1997)
Verification & sources · governance
FAQ
Frequently asked questions
- Does VBAC Success Score (Flamm Model) upload patient data? Where is it calculated?
- Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
- How is VBAC Success Score (Flamm Model) calculated in practice? Can you show a worked example?
- Inputs: Maternal age < 40 years No (0), Vaginal birth history Vaginal birth before cesarean only (1), Prior cesarean for reason other than failure to progress No — failure to progress / CPD (0), Cervical effacement at admission 25–75% (1), Cervical dilation ≥ 4 cm at admission No (0) → Result: Flamm VBAC 2 pts（Cohort success band: ~49% success (score 0–2), Range: 0–10 points (Flamm 1997)） Inputs: Maternal age < 40 years No (0), Vaginal birth history No previous vaginal birth (0), Prior cesarean for reason other than failure to progress No — failure to progress / CPD (0), Cervical effacement at admission < 25% (0), Cervical dilation ≥ 4 cm at admission No (0) → Result: Flamm VBAC 0 pts（Cohort success band: ~49% success (score 0–2), Range: 0–10 points (Flamm 1997)）