Bishop score
Cervical readiness before induction of labour
- NICE NG207 (2021)
Sources last checked: 2026-10-13
Bishop score
Cervical readiness before induction of labour
The original 1964 score, with effacement in %. “Modified” versions replace effacement with cervical length in cm and add or subtract points for parity and pre-eclampsia — the versions are not interchangeable. Subjective, with considerable inter-observer variation; transvaginal cervical length is an alternative.
Interpretation
| 0–6 — unfavourable | For Bishop ≤ 6, NICE NG207 recommends induction with a prostaglandin (dinoprostone or low-dose oral misoprostol) or a mechanical method. |
|---|---|
| 7–8 — favourable (> 6) | For Bishop > 6, NICE NG207 recommends induction with amniotomy and intravenous oxytocin. |
| 9–13 — highly favourable | Bishop 1964: ≥ 9 was the threshold at which elective induction proved reliably successful. NICE: ≥ 8 generally means the cervix is ready to dilate. |
What is the Bishop score?
The Bishop score rates five findings on vaginal examination — dilatation, effacement, station, consistency and position of the cervix — for a total of 0–13. Edward Bishop described it in 1964 to select women for elective induction; inductions with a score of 9 or more succeeded reliably. It remains the standard way to decide on cervical ripening before induction.
When to use it
- Before induction of labour to choose between cervical ripening and amniotomy/oxytocin
- Reassessing progress during cervical ripening
- Counselling about the likely course of an induction
When not to use it
- When vaginal examination is contraindicated (e.g. placenta praevia)
- As a predictor of spontaneous preterm birth — use transvaginal cervical length
How it is calculated
| Criterion | Points |
|---|---|
| Cervical dilatation | |
| Closed (0 cm) | 0 |
| 1–2 cm | 1 |
| 3–4 cm | 2 |
| ≥ 5 cm | 3 |
| Effacement | |
| 0–30 % | 0 |
| 40–50 % | 1 |
| 60–70 % | 2 |
| ≥ 80 % | 3 |
| Station of the presenting part | |
| −3 | 0 |
| −2 | 1 |
| −1 or 0 | 2 |
| +1 or +2 | 3 |
| Cervical consistency | |
| Firm | 0 |
| Medium | 1 |
| Soft | 2 |
| Cervical position | |
| Posterior | 0 |
| Mid | 1 |
| Anterior | 2 |
Clinical pearls and limitations
- The original 1964 score, with effacement in %. “Modified” versions replace effacement with cervical length in cm and add or subtract points for parity and pre-eclampsia — the versions are not interchangeable. Subjective, with considerable inter-observer variation; transvaginal cervical length is an alternative.
- NICE NG207 uses ≤ 6 versus > 6 to choose the induction method.
- Dilatation contributes most to the predictive value.
- Modified Bishop versions use cervical length in cm — record which version you use.
Frequently asked questions
What is a favourable Bishop score?
Above 6 is usually considered favourable; 8 or more means the cervix is generally ready to dilate. 6 or less is unfavourable; for this range NICE NG207 recommends induction with a prostaglandin or a mechanical method.
What does station −3 to +2 mean?
The level of the presenting part relative to the ischial spines in cm: negative above, 0 at, positive below the spines.
Is there a modified Bishop score?
Yes, several. The most common replaces effacement with cervical length; some add points for parity or subtract for pre-eclampsia.
Evidence and guidelines
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