How this instrument works
The Bishop score turns five things a clinician already found on a pelvic exam into a single number describing how ready a cervix is for labor induction. Cervical dilation, effacement, fetal station, consistency, and position each earn points on their own small scale, and this instrument's whole job is to add those five numbers together — nothing more.
Edward Bishop introduced the scale in 1964, scoring pelvic findings in women being considered for elective induction and correlating the total against how labor actually went. The American College of Obstetricians and Gynecologists still reproduces his five-part system in its own guidance on induction, which is why the same 0-to-13 scale is still what appears on labor-and-delivery charts today.
This calculator does not examine anyone and cannot assign any of the five component scores itself — a clinician has to place fingers on the cervix, feel its dilation, effacement, consistency, and position, and locate the fetal head's station, before any of these five fields mean anything. What runs here is the addition after that exam, not a substitute for it, and not a tool a patient or family member should use to interpret an exam nobody trained has performed.
A higher total, generally 8 or above, describes a cervix considered favorable or ripe, where induction tends to behave much like labor that starts on its own. A lower total describes a cervix generally considered unfavorable, where induction is more likely to take longer or fail to progress to vaginal delivery. Either way, the number is one input a clinician weighs alongside gestational age, the reason induction is being considered, and the rest of the clinical picture — never a verdict by itself.
- Select Cervical dilation from the exam findings: Closed, 1-2 cm, 3-4 cm, or 5 cm or more.
- Select Effacement as found on exam: 0-30%, 40-50%, 60-70%, or 80% or more.
- Select Fetal station: -3, -2, -1 or 0, or +1 or +2, exactly as documented.
- Select Cervical consistency: Firm, Medium, or Soft.
- Select Cervical position: Posterior, Mid / central, or Anterior.
- Read the Bishop score (0-13) — the sum of all five selections, computed automatically.
Worked example — five findings, each worth 1 point
A clinician documents 1-2 cm dilation (1 point), 40-50% effacement (1 point), station -2 (1 point), medium consistency (1 point), and a mid/central position (1 point). Enter each finding into its matching field and the five ones add straight across: 1 + 1 + 1 + 1 + 1 = 5, a Bishop score in the range generally considered less favorable for induction, though far from the lowest possible reading.
The scale's two extremes bound that middle case. A closed, uneffaced, firm, posterior cervix with the head still at station -3 scores zero on every component — 0 + 0 + 0 + 0 + 0 = 0, the least favorable exam this scale can describe. A cervix already 5 cm or more dilated, 80%+ effaced, at station +1/+2, soft, and anterior scores the maximum on every component — 3 + 3 + 3 + 2 + 2 = 13, the most favorable reading, where induction is expected to closely resemble labor that starts on its own.
Questions
What does a Bishop score of 5 mean?
A score of 5 sits below the commonly cited cutoff of 8, so the cervix in that exam is generally described as less favorable for induction — labor might take longer to establish or be more likely to need a cervical-ripening step first. It is still just one data point: gestational age, the reason induction is being considered, and the rest of the clinical picture all factor into what a clinician actually decides to do next.
Does this calculator examine the cervix for me?
No. Every one of the five numbers it adds — dilation, effacement, station, consistency, and position — comes from a clinician's fingers on an actual pelvic exam; nothing about this page substitutes for that exam or tells anyone how to perform it. This instrument only carries out the arithmetic after the exam is finished, and it is not built for a patient or anyone untrained to score themselves or another person.
What Bishop score counts as favorable for induction?
A total of 8 or higher is generally considered a favorable, or ripe, cervix, where induction is expected to proceed much like spontaneous labor. Scores below that threshold are usually described as unfavorable, sometimes prompting a cervical-ripening method before induction begins. The cutoff is a guideline drawn from Bishop's original correlation between score and induction outcome, not a fixed rule applied identically to every patient.
What are the lowest and highest possible Bishop scores?
Zero and thirteen. A score of 0 describes a closed, firm, posterior cervix with effacement under 30% and the fetal head still high at station -3 — the least favorable starting point. A score of 13 describes a cervix already 5 cm or more dilated, 80%+ effaced, soft, anterior, and at station +1/+2 — the most favorable reading the scale allows.
Is the Bishop score enough on its own to decide on induction?
No. It is one structured piece of the pelvic exam, not the whole clinical picture. A clinician also weighs why induction is being considered, gestational age, prior deliveries, and maternal and fetal wellbeing before deciding whether and how to proceed. ACOG's own guidance on induction of labor treats the score as a supporting input rather than a stand-alone decision rule.
Who created the Bishop score and when?
Obstetrician Edward Bishop published it in 1964, in a paper describing pelvic scoring for elective induction, after tracking how the five-part total correlated with labor outcomes in women being induced. The scale has changed little since; it still appears, largely unaltered, in current obstetric guidance six decades later.
References
- Bishop EH, 1964, Obstetrics & Gynecology (PubMed)
- ACOG Practice Bulletin No. 107, Induction of Labor (PubMed)
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.