terican

Last verified · v1.0

Calculator · health

Bishop Score Calculator

Calculate the Bishop Score by entering cervical dilation, effacement, fetal station, consistency, and position to assess readiness for labor induction.

FreeInstantNo signupOpen source

Inputs

Bishop Score

—

Explain my result

0/3 free

Get a plain-English breakdown of your result with practical next steps.

Bishop Score—points

The formula

How the
result is
computed.

What Is the Bishop Score?

The Bishop Score is a standardized pre-labor cervical assessment scale first described by Dr. Edward Bishop in 1964. Obstetricians, midwives, and labor nurses use this 13-point scoring system to evaluate cervical readiness and predict the likelihood of successful labor induction. A higher total score reflects a more favorable, well-ripened cervix and a greater probability of achieving vaginal delivery following induction.

The Bishop Score Formula

The calculator sums five discrete parameters assessed during digital pelvic examination:

Bishop Score = D + E + S + C + P

Each letter represents one scored component: D = Cervical Dilation, E = Cervical Effacement, S = Fetal Station, C = Cervical Consistency, and P = Cervical Position. Individual components score between 0 and 2 or 0 and 3 points, and the maximum achievable total is 13 points.

Component 1: Cervical Dilation (D)

Dilation measures how many centimeters the cervical os has opened. A closed cervix scores 0 points, 1-2 cm scores 1 point, 3-4 cm scores 2 points, and 5 cm or greater scores 3 points. Dilation carries the most clinical weight among the five components and is the strongest single predictor of induction success.

Component 2: Cervical Effacement (E)

Effacement describes how much the cervix has thinned and shortened, expressed as a percentage of its original length. Scoring: 0-30% effaced = 0 points, 40-50% = 1 point, 60-70% = 2 points, and 80% or more = 3 points. Progressive effacement reflects advancing cervical ripening in the days before labor.

Component 3: Fetal Station (S)

Station records the position of the fetal presenting part in centimeters relative to the maternal ischial spines. Station -3 scores 0 points, station -2 scores 1 point, station -1 or 0 scores 2 points, and station +1 or +2 scores 3 points. Greater fetal descent is associated with more imminent labor and a higher likelihood of successful induction.

Component 4: Cervical Consistency (C)

Consistency describes the palpated firmness of the cervix during digital examination. A firm cervix — often compared to the cartilage at the tip of the nose — scores 0 points. A medium cervix scores 1 point. A soft cervix — comparable in feel to the lips — scores 2 points. Cervical softening is a hallmark of prelabor cervical ripening driven by prostaglandin activity.

Component 5: Cervical Position (P)

Position describes the orientation of the cervical os relative to the vaginal axis. A posterior cervix scores 0 points, a mid-position cervix scores 1 point, and an anterior cervix scores 2 points. As term approaches, the cervix typically rotates forward from a posterior to an anterior position, becoming more accessible during examination.

Interpreting the Total Bishop Score

Clinical guidelines establish the following thresholds for interpretation:

  • Score 0-5 (Unfavorable): The cervix is not adequately prepared for induction. Cervical ripening agents — including pharmacological options such as misoprostol or dinoprostone, or mechanical methods such as a transcervical Foley catheter — are recommended before induction proceeds.
  • Score 6-8 (Moderately Favorable): Induction may proceed, though duration and outcome depend on additional clinical factors including parity and indication for induction.
  • Score 9-13 (Favorable): The cervix is well-ripened and ready. Induction success rates in this range approach those observed with spontaneous labor onset.

Research published in BMC Pregnancy and Childbirth (2019) developed a validated mathematical model demonstrating that the Bishop Score predicts mean time to delivery following cervical ripening, confirming its quantitative clinical utility. The American College of Obstetricians and Gynecologists (ACOG) Practice Bulletin No. 107 formally recommends assessing cervical status with the Bishop Score before elective induction, noting that a score below 6 warrants cervical ripening intervention prior to oxytocin administration.

Clinical Example

A patient presents at 41 weeks gestation for elective induction. On examination: cervix dilated 2 cm (1 point), 50% effaced (1 point), fetal station -1 (2 points), medium consistency (1 point), mid position (1 point). Total Bishop Score = 6. This borderline result prompts a shared decision between proceeding directly with oxytocin or first applying a cervical ripening agent to optimize conditions for vaginal delivery.

Limitations and Complementary Assessment

The Bishop Score depends on subjective digital assessment, which introduces inter-examiner variability. Transvaginal ultrasound measurement of cervical length has been evaluated as an objective complement. A peer-reviewed comparative study found that transvaginal cervical length measurement provides comparable predictive accuracy for Cesarean delivery risk, suggesting both tools serve complementary roles in pre-induction assessment. Despite this limitation, the Bishop Score remains the most widely validated and universally used clinical tool for evaluating cervical readiness worldwide.

Reference

Frequently asked questions

What is a good Bishop Score for labor induction?
A Bishop Score of 9 or higher is considered favorable for labor induction, indicating the cervix is well-ripened and ready. Research shows that induction success rates at this level approach those of spontaneous labor onset. Scores of 6 to 8 represent moderate favorability, while scores of 5 or below indicate an unfavorable cervix where cervical ripening agents such as prostaglandins are typically recommended before induction begins.
What does a Bishop Score of 6 mean?
A Bishop Score of 6 indicates a borderline or moderately favorable cervix that has begun preparing for labor but may not be fully ready for direct induction. Clinicians may proceed with oxytocin induction or first administer a cervical ripening agent such as misoprostol or dinoprostone. The decision depends on additional factors including parity, gestational age, fetal status, and the urgency of the indication for induction.
What happens when the Bishop Score is low?
When the Bishop Score is 5 or below, the cervix is considered unfavorable and direct induction is less likely to succeed. Clinicians typically initiate cervical ripening before induction using pharmacological agents such as prostaglandin E1 analogues (misoprostol) or prostaglandin E2 preparations (dinoprostone). Mechanical methods including a transcervical Foley catheter or osmotic dilators are alternative options. The Bishop Score is reassessed after ripening to determine readiness to proceed.
How is the Bishop Score calculated step by step?
The Bishop Score is calculated by scoring five cervical and fetal parameters and summing the results. Step 1: Score cervical dilation 0-3 points based on centimeters open. Step 2: Score cervical effacement 0-3 points based on percentage thinned. Step 3: Score fetal station 0-3 points based on position relative to the ischial spines. Step 4: Score cervical consistency 0-2 points for firm, medium, or soft texture. Step 5: Score cervical position 0-2 points for posterior, mid, or anterior orientation. The total ranges from 0 to 13.
What is the maximum possible Bishop Score?
The maximum possible Bishop Score is 13 points. This maximum is reached when all five parameters receive their highest scores: cervical dilation of 5 cm or greater (3 points), effacement of 80% or more (3 points), fetal station of +1 or +2 (3 points), soft cervical consistency (2 points), and anterior cervical position (2 points). A score of 13 indicates an optimally favorable cervix with a very high probability of successful vaginal delivery following induction.
How accurate is the Bishop Score at predicting successful labor induction?
The Bishop Score demonstrates moderate predictive accuracy for induction success, with higher scores consistently associated with shorter induction-to-delivery intervals and lower Cesarean delivery rates. A validated mathematical model published in BMC Pregnancy and Childbirth (2019) confirmed its quantitative predictive value for time to delivery after cervical ripening. Accuracy varies with parity, gestational age, and indication for induction. Nulliparous patients generally require higher scores than multiparous patients to achieve equivalent induction success rates.