Bishop Score Calculator – Labor Induction
Enter the five findings of a cervical examination — dilation, effacement, station, consistency and position — to get the total Bishop score and an interpretation of how favorable the cervix is for induction of labor.
Score a Cervical Examination
Bishop Score Formula
Where:
- \(B\) — total Bishop score (0–13)
- \(D\) — points for cervical dilation (0–3)
- \(E\) — points for cervical effacement (0–3)
- \(S\) — points for fetal station (0–3)
- \(C\) — points for cervical consistency (0–2)
- P\) — points for cervical position (0–2)
The Bishop score adds up the points from five components of a cervical examination. The higher the total, the more "ripe" (favorable) the cervix is and the more likely an induction of labor will succeed without a cesarean delivery.
Bishop Score – Calculation Example
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Example: a woman at 39 weeks is scheduled for an induction. Her cervical examination shows a dilation of 1–2 cm, effacement of 40–50%, fetal station at -2, medium consistency and a middle position.
\[ B = 1 + 1 + 1 + 1 + 1 = 5 \]
Result: a total Bishop score of 5 / 13 — an intermediate (equivocal) cervix. Induction may succeed, but many providers recommend cervical ripening before starting oxytocin, especially in first-time mothers.
How to Use the Bishop Score Calculator
- Select the Cervical dilation measured at the examination: Closed (0 cm), 1–2 cm, 3–4 cm or 5–6 cm.
- Select the Cervical effacement — how much the cervix has thinned: 0–30%, 40–50%, 60–70% or 80–100%.
- Select the Fetal station, the level of the baby's presenting part relative to the ischial spines: -3, -2, -1 to 0, or +1 to +2.
- Select the Cervical consistency felt on palpation: Firm, Medium or Soft.
- Select the Cervical position inside the vagina: Posterior, Middle or Anterior.
- Read the Total Bishop score, the Interpretation and the component-by-component breakdown of where the points came from.
What Is the Bishop Score?
The Bishop score, introduced by Edward H. Bishop in 1964, is the standard method obstetric teams use to describe how ready the cervix is for labor. Before an induced labor, a clinician performs a vaginal examination and grades five findings: how open the cervix is (dilation), how short and thin it has become (effacement), how far the baby's head has descended into the pelvis (station), the texture of the cervix (consistency) and its location in the vagina (position).
Each finding is converted to points, and the sum — from 0 to 13 in this modified version — predicts the likelihood that an induction will lead to a vaginal delivery. A high score means the body is already moving toward labor on its own; oxytocin or breaking the waters (amniotomy) is usually enough to get things going. A low score means the cervix is still long, closed and firm, so ripening with prostaglandin gels or a mechanical balloon catheter is typically attempted first.
Dilation, effacement and station carry the most predictive weight; consistency and position add refinement. Research consistently shows that the higher the score, the shorter the time to delivery and the lower the risk of a failed induction ending in cesarean. Remember that the score describes a single moment: it can change within hours, and it is only one of many factors — such as parity (whether the mother has given birth before), gestational age and the reason for induction — that shape the plan.
Scoring Table
| Component | 0 points | 1 point | 2 points | 3 points |
|---|---|---|---|---|
| Dilation | Closed (0 cm) | 1–2 cm | 3–4 cm | 5–6 cm |
| Effacement | 0–30% | 40–50% | 60–70% | 80–100% |
| Station | -3 | -2 | -1 to 0 | +1 to +2 |
| Consistency | Firm | Medium | Soft | — |
| Position | Posterior | Middle | Anterior | — |
Limitations and Practical Tips
- The score is examiner-dependent. Two clinicians can grade effacement or consistency differently, so a difference of a point or two between visits is common and usually not meaningful. Focus on the trend rather than a single number.
- Interpretation thresholds vary by protocol. This calculator uses the common cut-offs — 4 or less unfavorable, 5–6 intermediate, 7 or more favorable — but some hospitals use a threshold of 6 or 8 when deciding on ripening, and parity is often weighed alongside the score.
- A low score is not a failed induction. It simply means ripening is usually attempted first. Many women with low initial scores go on to deliver vaginally.
- This tool is for information and shared decision-making. The decision whether, when and how to induce labor always belongs to you and your obstetric team — never change or delay a care plan based on a self-computed score.
If you are monitoring your pregnancy, you may also find our contraction timer useful once labor begins, and the Apgar score calculator explains the quick assessment performed on your newborn right after birth. The pregnancy due date calculator can help you track how far along you are.
Frequently Asked Questions
What is a good Bishop score for induction?
A score of 7 or higher is generally considered favorable — the cervix is ripe and induction is likely to succeed without ripening. Scores of 5–6 are intermediate, meaning induction may work but ripening is often recommended first, especially for first-time mothers. A score of 4 or less is unfavorable, and prostaglandins or a balloon catheter are usually tried before oxytocin. Some hospitals use slightly different cut-offs (6 or 8), so ask your provider which threshold their protocol uses.
How do I calculate the Bishop score by hand?
Assign points to each of the five findings and add them up: dilation (closed = 0, 1–2 cm = 1, 3–4 cm = 2, 5–6 cm = 3), effacement (0–30% = 0, 40–50% = 1, 60–70% = 2, 80–100% = 3), station (-3 = 0, -2 = 1, -1 to 0 = 2, +1 to +2 = 3), consistency (firm = 0, medium = 1, soft = 2) and position (posterior = 0, middle = 1, anterior = 2). The maximum is 13 points in this modified version. A quick shortcut: dilation and station alone give a rough sense, since they carry the most predictive weight.
What is the difference between the original and modified Bishop score?
Bishop's original 1964 paper scored effacement differently, using cervical length in centimetres rather than a percentage, and some versions weight the components differently. The modified version used here substitutes percentage effacement (0–30% up to 80–100%) for length and is what most hospitals use today, with a 0–13 range. Some protocols also drop consistency and position entirely and use only dilation, effacement and station — a simplified score that performs almost as well.
Can the Bishop score predict whether I'll need a C-section?
It predicts probability, not certainty. A low score is associated with a higher chance of a failed induction ending in cesarean, and a high score with a shorter labor and higher vaginal delivery rate. But many women with low initial scores deliver vaginally after successful ripening, and outcomes also depend heavily on whether you have given birth before, your gestational age and the reason for induction. Treat the score as one input into the plan, not a verdict.
Does a first-time mother need a higher Bishop score?
Yes, in practice. Labor induction in a first pregnancy (nulliparous) is more likely to be prolonged or fail at any given score, so many providers apply stricter thresholds — for example, treating 5–6 as unfavorable for a first-time mother while accepting it for a woman who has delivered vaginally before. Parity is often weighed alongside the score when deciding whether ripening is needed before oxytocin.
How quickly can the Bishop score change?
The score describes a single moment, and the cervix can change noticeably within hours — particularly once contractions, prostaglandins or a balloon catheter are at work. It is also examiner-dependent: two clinicians can grade effacement or consistency a point apart, so a small change between visits is common and usually not meaningful. A trend across repeated examinations is more informative than any single number.
Can I measure my own dilation and effacement at home?
No — the components require a trained vaginal examination. Dilation and effacement are felt with gloved fingers against the cervix, station is judged relative to the ischial spines inside the pelvis, and consistency can only be assessed by palpation. Self-examination risks introducing infection and produces unreliable numbers. Use this calculator only to interpret findings your clinician has already reported to you, and discuss any concerns about timing or method of induction with your obstetric team.