Obstetrics
Bishop Score
Cervical favourability for induction of labour.
Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.
Background
The Bishop score assesses how favourable, or ripe, the cervix is before induction of labour, helping to predict the likelihood of a successful and timely induction. It is based on a vaginal examination scoring five features: cervical dilation, effacement (or length), station of the presenting part, cervical consistency and cervical position. Each is scored and summed, with a maximum of around 13. A higher score reflects a more favourable cervix.
Interpreting the result
A score of 8 or above generally indicates a favourable cervix, where induction is likely to succeed and may proceed to amniotomy and oxytocin. A score of 5–7 is intermediate. A low score (0–4, and often 5–6) suggests an unfavourable cervix that may benefit from cervical ripening before formal induction. The score predicts the probability of successful induction rather than guaranteeing the outcome.
Advice
Generally a score ≥8 suggests a favourable cervix; ≤5–6 may prompt cervical ripening. Follow local obstetric guidance.
Worked example
A woman being assessed for induction has a cervix dilated 3 cm, well effaced, soft, in a mid position with the head at a low station, giving a Bishop score of around 9. This favourable score suggests induction is likely to succeed without prior ripening.
Pearls / pitfalls
- It guides whether cervical ripening is needed before induction; a low score does not preclude induction but predicts a longer, less certain process.
- Assessment is operator-dependent, and inter-observer variation in dilation, effacement and station is common.
- A modified Bishop score is sometimes used, simplifying some components — be clear which version is being applied.
- The score informs but does not replace individualised obstetric assessment of the woman and fetus.
Evidence & validation
Originally described by Bishop for predicting successful elective induction and validated in subsequent obstetric practice. It is embedded in induction-of-labour guidance, including NICE, as the standard assessment of cervical favourability.
Frequently asked questions
What Bishop score is favourable for induction?
A score of 8 or above generally indicates a favourable cervix where induction is likely to succeed. Lower scores, particularly 5–6 or below, may prompt cervical ripening first.
What does a low Bishop score mean?
A low score reflects an unfavourable, unripe cervix, so induction is less likely to succeed quickly. Cervical ripening is often offered before proceeding to amniotomy and oxytocin.
What does the Bishop score measure?
It scores five features on vaginal examination — cervical dilation, effacement or length, station of the presenting part, cervical consistency and cervical position — to estimate how ready the cervix is for labour.
Does a high score guarantee a successful induction?
No. A high score makes a successful, timely induction more likely but does not guarantee it, as labour also depends on fetal position, uterine activity and other individual factors.
Is the assessment reproducible?
It is somewhat operator-dependent, and different examiners may grade dilation, effacement and station differently. This inter-observer variation should be kept in mind when interpreting borderline scores.
References
- Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol. 1964;24:266–268.
- NICE NG207: Inducing labour. 2021.
About the creator
Bishop EH
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