Bishop Score Calculator

The Bishop score is a five-component pre-labor scoring system developed by Edward Bishop and published in 1964 in “Pelvic scoring for elective induction” (Obstetrics & Gynecology 24(2):266–268). It grades cervical readiness for induction of labor — dilation, effacement, station, consistency, and position — from findings on manual vaginal examination performed by a trained professional. The total ranges from 0 to 13. It is an educational and clinical assessment aid, not medical advice; clinical decisions about induction belong to a qualified obstetric clinician.

Cervical dilation: closed = 0, 1–2 cm = 1, 3–4 cm = 2, 5 cm or more = 3. Cervical effacement: 0–30% = 0, 40–50% = 1, 60–70% = 2, 80% or more = 3. Fetal station: −3 = 0, −2 = 1, −1 or 0 = 2, +1 or +2 = 3, measured against the ischial spines. Cervical consistency: firm = 0, medium = 1, soft = 2. Cervical position: posterior = 0, mid = 1, anterior = 2. Consistency and position have no 3-point level, so the maximum total is 13.

The lowest possible score is 0 and the highest is 13. Position and consistency are each scored 0–2, while dilation, effacement, and station are each scored 0–3, giving 3 + 3 + 3 + 2 + 2 = 13 at most.

In classic clinical use the score is described in three bands: 8 or more is considered a favorable cervix, 6–7 is intermediate, and 5 or less is unfavorable. A score of 9 is described in clinical references as conveying a high likelihood of successful induction. For research purposes, a score of 4 or less identifies an unfavorable cervix. These are descriptive readiness categories, not instructions, and the score can be recalculated as the pregnancy progresses. Only a qualified clinician can interpret the score for a real patient.

The simplified Bishop score (Laughon et al., Obstetrics & Gynecology, 2011) uses only three components — dilation, station, and effacement — dropping cervical position and consistency, for a maximum of 9 points instead of 13. In the original study, a simplified score greater than 5 had predictive ability for vaginal delivery comparable to the original score greater than 8 (positive predictive value 87.7% versus 87.0%).

One common modification replaces effacement (a percentage) with cervical length in centimeters: over 3 cm = 0, over 2 cm = 1, over 1 cm = 2, over 0 cm = 3. Cervical length can be measured on ultrasound and may have less examiner-to-examiner variability. This variant is shown for information only and is not computed by this calculator.

No. The Bishop score describes cervical readiness on a 0–13 scale; it does not recommend, approve, or rule out induction of labor. Decisions about induction involve many factors beyond this score — gestational age, maternal and fetal conditions, and clinical judgment — and must be made with a qualified obstetric clinician. This calculator is an educational tool and is not medical advice.

Some teaching versions of the score add or subtract points for special circumstances: add 1 point for preeclampsia and 1 point for each prior vaginal delivery; subtract 1 point for a post-term pregnancy, for nulliparity (no prior vaginal delivery), and for premature or prolonged rupture of membranes. These modifiers are not part of the ACOG-published 0–13 table, and this calculator does not apply them.

The published table lists discrete bands (for example effacement 0–30%, then 40–50%), leaving small gaps. In practice examiners assign the closest band. The select menus on this page use the literal published bands; for manual numeric entry this calculator resolves in-between values at the midpoints between bands (for example effacement below 35% scores 0 and 35–54% scores 1).

No. The entire calculator runs locally in your browser using JavaScript. There are no accounts, no external requests, and no data leaves your device.