Pregnancy · Induction
Bishop Score for Induction
Bishop score (Edward Bishop 1964) — 5-component cervical assessment predicting induction success. Plus what each band means, cervical ripening methods, how long induction takes, alternatives, the ARRIVE trial.
Last reviewed 29 May 2026
Modified Bishop Score
Pre-induction cervical readiness
Score all five components to see the total.
Bishop score is the standard pre-induction assessment in NICE CG70 and ACOG PB 107. It is a clinician’s assessment tool — patients shouldn’t score themselves, but understanding the components helps inform the induction conversation.
What does this mean?
The Bishop score tells you how “ripe” (ready) the cervix is for labour. A score ≥ 8 means induction with oxytocin alone has a similar success rate to spontaneous labour; 6–7 is borderline; ≤ 5 usually means cervical ripening is needed first (prostaglandin gel/tablet, misoprostol, or a Foley balloon over 6–12 h) so the oxytocin drip has something to work on. The five components are physical findings only a clinician can assess on vaginal exam — dilation, effacement (thinning), station (how low the baby sits), consistency, and cervical position. Knowing your score helps frame the induction conversation: a low score means “expect 12– 24 h ripening before the active labour drip”, a high one means “we’ll start with the drip and you may meet your baby within the day”.
What is the Bishop score?
Clinician-administered 5-component cervical assessment used to predict success of labour induction. Introduced by Edward Bishop in 1964. Scores DILATION, EFFACEMENT, STATION, CONSISTENCY, POSITION of the cervix — total 0-13. The single best predictor of induction success.
What does my Bishop score mean for induction?
- 0-5 (unfavourable / unripe): success rate ~50%; needs cervical ripening (PGE2, misoprostol, Foley balloon) first. 12-24+ hours.
- 6-7 (intermediate): some teams ripen first, others try oxytocin straight away.
- 8-13 (favourable / ripe): excellent success rate (~95%); often just oxytocin and amniotomy.
The 5 components
- Dilation (cm open): 0 closed = 0; 1-2 = 1; 3-4 = 2; 5+ = 3.
- Effacement (% thinned): 0-30% = 0; 40-50% = 1; 60-70% = 2; 80%+ = 3.
- Station (baby’s head vs ischial spines): -3 = 0; -2 = 1; -1, 0 = 2; +1, +2 = 3.
- Consistency: firm = 0; medium = 1; soft = 2.
- Position: posterior = 0; mid = 1; anterior = 2.
What is cervical ripening?
Making an unfavourable cervix ready for labour. Methods:
- Prostaglandin E2 (PGE2 / dinoprostone) gel or pessary — softens cervix over 6-24 hours.
- Misoprostol — off-label UK; standard US. Oral or vaginal, smaller doses repeated.
- Foley balloon — urinary catheter inflated above cervix puts pressure → ripens.
- Osmotic dilators — less common.
- Membrane sweep — see /calculators/membrane-sweep.
How long does induction take?
Variable. Average: 24-48 hours from start to delivery. Steps: ripening if needed (6-24 hours); amniotomy when favourable; oxytocin drip; active labour (6-12 hours); pushing. First-time mums longer (24-48 hours); subsequent shorter (12-24 hours). Plan for slow journey — bring book / entertainment for early hours.
Reasons for induction
- Medical: post-term (41+ weeks), preeclampsia, GDM on insulin, waters broken, growth restriction, reduced movements, ICP, previous stillbirth, certain maternal conditions.
- Elective: maternal request after 39 weeks (some units; ACOG ARRIVE supports for low-risk first-time mums).
What is the ARRIVE trial?
Major 2018 US trial (Grobman, NEJM) of 6,106 low-risk first-time mothers. Compared INDUCTION AT 39 WEEKS vs EXPECTANT MANAGEMENT. Found:
- Lower caesarean rate with induction (18.6% vs 22.2%).
- Lower hypertensive disorder rate.
- No difference in perinatal mortality.
Changed many US units toward offering 39-week induction to low-risk nulliparous. UK NHS less enthusiastic; ACOG 2019 supports informed choice.
Different scenarios — what your score means
Scenario 1: Bishop 2 at 41+0 weeks (post-dates induction)
Unfavourable. Likely ripening with PGE2 pessary first — 12-24 hours. Reassess Bishop after; if improved, oxytocin + ARM (artificial rupture of membranes). Total process 24-48+ hours common for first baby.
Scenario 2: Bishop 8 at 39 weeks induction (maternal request)
Favourable. Likely straight to ARM + oxytocin. Active labour within 4-8 hours; delivery often within 12-18 hours. Discuss pain relief in advance; epidural often desired given oxytocin contractions.
Scenario 3: Bishop 5 at 40+6 weeks, GDM on insulin
Borderline. Team may ripen first (mini-PGE2) or try oxytocin given GDM time-pressure. Continuous CTG. Plan for 24-48 hour journey. Consider epidural early.
Scenario 4: Bishop 3 at 36 weeks, severe preeclampsia
Unfavourable but induction medically necessary. Ripening with PGE2. If unable to ripen / progress, may proceed to caesarean. Magnesium sulphate for seizure prophylaxis. Tight BP control.
Scenario 5: Bishop 1 at 41 weeks, previous CS, wanting VBAC
Unfavourable. Induction with PGE2 increases uterine rupture risk in VBAC (~1% vs ~0.4% spontaneous). Foley balloon often preferred for VBAC induction. Continuous CTG. Detailed discussion with team about risks vs benefits of induction vs repeat CS.
Can I avoid induction?
Sometimes yes, with shared decision-making. NICE NG207 recommends: discussion of risks/benefits at 41 weeks; offer induction at 41+ weeks; if you decline, increased monitoring (twice-weekly CTG, growth/amniotic fluid scans). Some women decline induction and labour spontaneously at 42+ weeks — statistically slightly increased perinatal mortality risk (~1 in 1000) which most decide is acceptable. INFORMED DECISION-MAKING is your right.
Is induction more painful than spontaneous labour?
Yes, generally. Reasons:
- Oxytocin contractions can be more INTENSE.
- Often requires CONTINUOUS CTG (restricts mobility).
- Often involves AMNIOTOMY (intensifies contractions).
- Longer duration = more cumulative pain.
- Earlier epidural uptake common (~40-60% of inductions).
Plan for pain management; discuss preferences in advance.
Care guidance — navigating induction
- Pack a long-stay bag — 2-3 nights worth.
- Bring entertainment — book, tablet, headphones.
- Snacks for partner — long hours.
- Comfortable clothing for ripening phase.
- Eat normally in early induction; restrict to clear fluids once in active labour.
- Move around during ripening when possible.
- Discuss pain relief plan with team.
- Birth partner support essential through long process.
- Don’t expect speed — many inductions are slow first labours in disguise.
- Ask questions — understand each step.
Sources
- Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol 1964.
- NICE NG207. Inducing labour. 2021.
- ACOG Practice Bulletin 107 (reaffirmed 2020). Induction of Labor.
- Grobman WA, et al. Labor Induction versus Expectant Management in Low-Risk Nulliparous Women (ARRIVE trial). N Engl J Med 2018.
- WHO. Recommendations for induction of labour.
- RCOG / RCM consent for caesarean discussion.
Frequently asked questions
What is the Bishop score?
Clinician-administered 5-component cervical assessment used to predict success of labour induction. Introduced by Edward Bishop in 1964. Scores DILATION, EFFACEMENT, STATION, CONSISTENCY, and POSITION of the cervix — total 0-13. Predicts induction success: FAVOURABLE cervix (Bishop ≥ 8) usually responds to oxytocin alone; UNFAVOURABLE (≤ 5) typically needs cervical RIPENING (prostaglandins, balloon catheter) first. Used by obstetric and midwifery teams across UK NHS, ACOG-affiliated centres, globally.
What does my Bishop score mean for induction?
BISHOP 0-5 (unfavourable / unripe): induction success rate ~50%; needs cervical ripening agent first (PGE2, misoprostol, Foley balloon). May take 12-24+ hours. BISHOP 6-7 (intermediate): some clinicians ripen first, others try oxytocin straight away. BISHOP 8-13 (favourable / ripe): excellent induction success rate (~95%); often just oxytocin and amniotomy (artificial rupture of membranes). The Bishop score is the SINGLE BEST predictor of induction outcome — informs the team's plan.
What are the 5 components of the Bishop score?
(1) DILATION (cervical opening cm): 0 closed = 0; 1-2 cm = 1; 3-4 cm = 2; 5+ cm = 3. (2) EFFACEMENT (cervical thinning %): 0-30% = 0; 40-50% = 1; 60-70% = 2; 80%+ = 3. (3) STATION (baby's head position relative to ischial spines): -3 = 0; -2 = 1; -1, 0 = 2; +1, +2 = 3. (4) CONSISTENCY: firm = 0; medium = 1; soft = 2. (5) POSITION (cervix in pelvis): posterior = 0; mid-position = 1; anterior = 2. Components added — max 13. Some modified versions add or omit components.
Why is my cervix being checked before induction?
To estimate INDUCTION SUCCESS PROBABILITY and PLAN THE METHOD. A 'ripe' (soft, partly dilated, well-positioned, baby low) cervix responds quickly to oxytocin. An 'unripe' cervix needs HORMONAL or MECHANICAL RIPENING first to soften and shorten it before the body responds. Without this assessment, inducing an unripe cervix often fails or takes longer, increasing caesarean rate. Knowing the score helps your team predict timing, choose method, and counsel you about expectations.
How is the cervix checked?
VAGINAL DIGITAL EXAMINATION — clinician (midwife or doctor) inserts two gloved fingers into the vagina to feel the cervix. Assesses dilation (how open), effacement (how thin), station (how low baby's head is), consistency (firm vs soft), and position (anterior vs posterior). Takes 1-2 minutes. Mildly uncomfortable; not normally painful. Best done between contractions if labour starting. Empty bladder first.
What is cervical ripening?
Making an unfavourable cervix more ready for labour. METHODS: (1) PROSTAGLANDIN E2 (PGE2 / dinoprostone) gel or pessary inserted vaginally — softens cervix over 6-24 hours. (2) MISOPROSTOL (off-label in UK; standard US) — oral or vaginal, smaller doses, repeated. (3) MECHANICAL — Foley urinary catheter inflated above cervix puts pressure → ripens; or osmotic dilators. (4) MEMBRANE SWEEP — see /calculators/membrane-sweep. May take 12-24 hours of ripening before oxytocin can effectively augment labour. Each method has pros and cons; team decision based on Bishop score, prior caesarean status, parity, fetal heart trace.
What's the difference between induction and augmentation?
INDUCTION = starting labour from no contractions. Requires ripening + oxytocin + possibly amniotomy. AUGMENTATION = strengthening contractions in an already-labouring woman (usually with oxytocin). Bishop score primarily for induction context. Augmentation reasons: slow progress, weak contractions, prolonged labour. Different decision process.
How long does induction take?
Variable. AVERAGE: 24-48 hours from start of induction to delivery. Steps: cervical ripening if needed (6-24 hours); amniotomy when cervix favourable; oxytocin drip; active labour (often 6-12 hours); pushing stage. FIRST-TIME mums tend to take longer (24-48 hours). Subsequent labours often shorter (12-24 hours). Some inductions go quickly (6-12 hours); some take days. Plan for slow journey; bring book / entertainment for early hours.
What are reasons for induction?
MEDICAL: post-term (41+ weeks); preeclampsia / hypertension; GDM (especially on insulin); waters broken without spontaneous labour (within 24-48 hours); growth restriction (FGR); reduced fetal movements; cholestasis (obstetric ICP); previous stillbirth; some maternal medical conditions. ELECTIVE: maternal request after 39 weeks (some units offer; ACOG 2018 ARRIVE trial supports for low-risk nulliparous); social reasons (rare in UK NHS). Each induction is a balanced decision — discuss with team.
Are there alternatives to induction?
EXPECTANT MANAGEMENT (continue waiting) — sometimes recommended if pregnancy still uncomplicated. MEMBRANE SWEEP (NICE recommends from 41 weeks) — can trigger spontaneous labour without formal induction. MORE LIBERAL POLICIES (e.g. natural birth approaches) extend waiting for some risk-free pregnancies. CAESAREAN (planned) — if induction is likely to fail or carries higher risk than CS in your specific case. Each has trade-offs. Make decision with your team using your specific clinical context.
What happens if induction fails?
DEFINITIONS: failed induction = no progress despite full ripening + oxytocin for 12-18+ hours. Options: (1) Pause and try again the next day. (2) Caesarean (most common — accounts for 15-20% of all CS births). (3) Continue if fetal heart trace OK and progress slowly being made. Failure rate higher with: unfavourable Bishop score, first baby, BMI ≥ 30, big baby, induction before 41 weeks. Discussion with team if induction not progressing.
Can I avoid induction?
Sometimes yes, with shared decision-making. NICE NG207 recommends: discussion of risks/benefits at 41 weeks; offer of induction at 41+ weeks; if you decline, increased monitoring (twice-weekly CTG, growth/amniotic fluid scans). Some women decline induction and labour spontaneously at 42+ weeks — statistically slightly increased perinatal mortality risk (~1 in 1000) which most women decide is acceptable. INFORMED DECISION-MAKING is your right; team should not pressure. Sometimes a few extra days while monitored leads to spontaneous labour.
What is the ARRIVE trial?
Major 2018 US trial (Grobman et al., NEJM) of 6,106 low-risk first-time mothers. Compared INDUCTION at 39 weeks vs EXPECTANT MANAGEMENT. Found: lower caesarean rate with induction (18.6% vs 22.2%); lower hypertensive disorder rate; no difference in perinatal mortality. Changed many US units toward offering 39-week induction to low-risk nulliparous. UK NHS less enthusiastic — caesarean rate baseline lower, different cohort. ACOG 2019 statement: offer informed choice of 39-week induction after thorough counselling.
Is induction more painful than spontaneous labour?
Yes, generally. Several reasons: (1) Oxytocin contractions can be MORE INTENSE than natural ones — quickly building up to strong without the gradual ramp-up. (2) Often requires CONTINUOUS CTG monitoring restricting mobility. (3) Often involves AMNIOTOMY which can intensify contractions. (4) Longer duration = more cumulative time in pain. (5) Earlier epidural uptake common (~40-60% of inductions get epidural vs 20-30% spontaneous). Plan for pain management; discuss preferences in advance.
Can I have an epidural during induction?
Yes — common and recommended for many inductions. Epidural can be sited any time after established active labour (usually 4+ cm). Some units site earlier in induction process given expected long course. Epidural during induction: doesn't slow induction progress significantly (recent research; older concern overstated); does increase chance of instrumental delivery slightly; significantly improves pain experience. Anaesthetist consultation is part of induction planning.
How does this relate to other calculators on BumpBites?
Companion: /calculators/membrane-sweep for stretch-and-sweep options; /calculators/contraction-timer for labour onset; /calculators/birth-plan-builder for labour preferences; /calculators/vbac-success if previous caesarean; /calculators/oxytocin-titration for the clinical infusion (clinician-facing); /calculators/cmqcc-pph-risk for postpartum haemorrhage risk.