Bishop’s Score: Parameters, Uses, and Clinical Significance
Introduction
Labor is one of the most critical events in obstetrics, marking the culmination of pregnancy. However, before initiating or inducing labor, healthcare providers must determine whether the cervix is ready for delivery. To evaluate this readiness objectively, the Bishop’s Score is widely used.
The Bishop’s Score is a pre-labor scoring system used to assess the favorability of the cervix for vaginal delivery. It helps obstetricians predict the success of labor induction and the likelihood of spontaneous vaginal delivery. Developed by Dr. Edward H. Bishop in 1964, this scoring system remains an essential tool in modern obstetrics.
This article provides a detailed overview of Bishop’s Score, including its parameters, uses, functions, interpretation, advantages, limitations, and clinical relevance.
What is Bishop’s Score?
The Bishop’s Score is a scoring system used to assess the readiness of the cervix for labor and to predict the likelihood of a successful induction of labor (IOL).
It evaluates specific cervical characteristics and fetal station through a pelvic examination, assigning a numerical value to each parameter. The total score helps determine whether the cervix is favorable, unfavorable, or ripe for labor induction.
In simple terms, the higher the Bishop’s Score, the more favorable the cervix is for induction and vaginal delivery.
History of Bishop’s Score
The Bishop’s Score was first described by Dr. Edward H. Bishop in 1964 at the University of Texas Southwestern Medical School. It was originally developed to evaluate multiparous women before elective induction of labor. Over time, it has been modified and adapted to include nulliparous women and to improve clinical applicability.
The original Bishop’s Score considered five parameters:
1. Cervical dilation
2. Cervical effacement
3. Cervical consistency
4. Cervical position
5. Fetal station
Later, some modifications added extra parameters such as presence of membranes and parity, but the classic five-component system remains the most widely used today.
Parameters of Bishop’s Score
The five key parameters of the Bishop’s Score are:
1. Cervical Dilatation
2. Cervical Effacement (or Length)
3. Cervical Consistency
4. Cervical Position
5. Fetal Station
Each parameter is given a score from 0 to 2 or 3, depending on its condition. The total Bishop’s Score can range from 0 to 13.
Let’s understand each parameter in detail.
1. Cervical Dilatation
Definition: Refers to the opening of the cervix, measured in centimeters.
Clinical significance: Greater dilation indicates readiness for labor.
Cervical Dilatation Score
Closed (0 cm) 0
1–2 cm 1
3–4 cm 2
≥5 cm 3
2. Cervical Effacement (or Length)
Definition: Refers to the thinning or shortening of the cervix during labor, expressed as a percentage or in centimeters.
Clinical significance: A fully effaced cervix is favorable for vaginal delivery.
Cervical Effacement Score
0–30% (or >2 cm long) 0
40–50% (or 1–2 cm) 1
60–70% (or <1 cm) 2
≥80% (or completely effaced) 3
3. Cervical Consistency
Definition: Refers to how soft or firm the cervix feels on examination.
Clinical significance: A softer cervix is more favorable for dilation and labor.
Cervical Consistency Score
Firm 0
Medium 1
Soft 2
4. Cervical Position
Definition: Refers to the orientation of the cervix in relation to the vaginal axis.
Clinical significance: A cervix that is anterior and aligned with the vaginal axis indicates readiness for delivery.
Cervical Position Score
Posterior 0
Mid-position 1
Anterior 2
5. Fetal Station
Definition: Indicates the position of the fetal head in relation to the maternal ischial spines.
Clinical significance: The lower the fetal head, the more favorable the condition for vaginal delivery.
Fetal Station (relative to ischial spines) Score
-3 0
-2 1
-1, 0 2
+1, +2 3
Calculation and Interpretation of Bishop’s Score
Once each parameter is assessed, the individual scores are added to get a total score (0–13).
Interpretation:
Total Score Interpretation Cervical Status
0–4 Unfavorable Cervix is not ready for labor induction
5–8 Moderately favorable May respond to induction methods
≥9 Favorable Indicates high likelihood of successful vaginal delivery
A score of 8 or more generally suggests that the cervix is ripe and labor induction is likely to be successful.
Modified Bishop’s Score
The Modified Bishop’s Score adjusts certain components to make them more applicable in modern practice. One common modification replaces effacement with cervical length (in cm) for easier measurement.
Modified Parameters:
1. Cervical dilation (cm)
2. Cervical length (cm)
3. Cervical consistency
4. Cervical position
5. Fetal station
Despite modifications, the clinical goal remains the same — to determine whether the cervix is favorable for induction.
Uses of Bishop’s Score
The Bishop’s Score plays a vital role in obstetric decision-making. Below are its main uses:
1. Assessment of Cervical Readiness for Labor
The primary use of Bishop’s Score is to assess whether the cervix is favorable for labor.
Helps determine the likelihood of spontaneous onset of labor.
2. Predicting Success of Labor Induction
A high Bishop’s Score (≥8) indicates a high probability of successful induction.
A low score (<5) suggests that induction may fail unless cervical ripening methods are used first.
3. Determining the Need for Cervical Ripening
When the cervix is unfavorable, cervical ripening agents (e.g., prostaglandins, misoprostol) can be administered before induction.
The Bishop’s Score guides the choice of induction method.
4. Deciding Mode of Delivery
Helps obstetricians decide whether a vaginal delivery is feasible or if a cesarean section might be safer.
5. Evaluating Labor Progress
Used to monitor changes in cervical status over time, especially in induced labor.
6. Clinical Research and Audits
Commonly used as a standardized tool in clinical trials and labor management studies.
Functions and Clinical Importance
The Bishop’s Score serves several important functions in obstetric practice:
1. Objective Evaluation: Provides an objective method to assess cervical status before induction.
2. Standardized Communication: Allows uniform reporting among healthcare providers.
3. Risk Prediction: Helps predict induction failure and reduce maternal and fetal complications.
4. Guidance for Management: Aids in selecting appropriate induction or augmentation methods.
5. Improving Outcomes: When used properly, it contributes to better maternal and neonatal outcomes.
Bishop’s Score and Labor Induction
Labor induction involves stimulating uterine contractions before the onset of spontaneous labor. The Bishop’s Score is essential to determine whether induction should be attempted.
When Bishop’s Score is Low (<5):
Cervix is considered unfavorable.
Cervical ripening is recommended before induction.
Methods include:
Prostaglandins (PGE1 or PGE2)
Mechanical dilators (Foley catheter, laminaria)
Membrane sweeping
When Bishop’s Score is High (≥8):
Cervix is favorable.
Labor induction can proceed directly using:
Oxytocin infusion
Amniotomy (artificial rupture of membranes)
Clinical Example:
A woman at 41 weeks of gestation has a Bishop’s Score of 9 → labor induction is likely to succeed.
Another woman at 39 weeks with a Bishop’s Score of 3 → needs cervical ripening before induction.
Advantages of Bishop’s Score
1. Simple and quick — can be performed during a routine vaginal exam.
2. Non-invasive — no equipment needed beyond standard examination tools.
3. Predictive value — helps forecast induction success and delivery outcomes.
4. Cost-effective — does not require laboratory or imaging tests.
5. Widely applicable — useful for both multiparous and nulliparous women.
Limitations of Bishop’s Score
Despite its usefulness, Bishop’s Score has some limitations:
1. Subjectivity: Findings may vary between examiners.
2. Invasive nature: Requires a vaginal examination, which may cause discomfort.
3. Limited precision: Other factors like uterine contractility and fetal position also influence labor outcomes.
4. Does not consider biochemical markers: Modern methods (like fetal fibronectin or cervical elastography) may provide additional predictive accuracy.
Recent Developments and Alternatives
Modern obstetrics has introduced new tools to complement or enhance the Bishop’s Score:
Ultrasound Cervical Length Measurement: Provides an objective and non-invasive measure of cervical ripeness.
Fetal Fibronectin Test: Predicts the likelihood of preterm labor.
Elastography: Evaluates cervical stiffness using ultrasound.
However, the Bishop’s Score remains the most practical and widely used method globally due to its simplicity and effectiveness.
Clinical Example: Bishop’s Score Calculation
Parameter Finding Score
Cervical dilatation 2 cm 1
Effacement 60% 2
Consistency Medium 1
Position Mid-position 1
Fetal station -1 2
Total Bishop’s Score 7
Interpretation: Moderately favorable cervix — induction may be successful, though cervical ripening could improve outcomes.
Bishop’s Score Chart (Summary)
Parameter 0 1 2 3
Dilatation (cm) Closed 1–2 3–4 ≥5
Effacement (%) 0–30 40–50 60–70 ≥80
Consistency Firm Medium Soft —
Position Posterior Mid Anterior —
Fetal Station -3 -2 -1/0 +1/+2
Practical Tips for Clinicians
1. Always perform the examination under aseptic conditions.
2. Evaluate the cervix gently to avoid membrane rupture.
3. Record the total Bishop’s Score clearly in the patient’s notes.
4. Combine with clinical judgment — not all cases fit numerical prediction.
5. Reassess the score after cervical ripening or induction attempts.
Conclusion
The Bishop’s Score is a time-tested, reliable, and simple method for evaluating cervical readiness for labor. It remains one of the most important tools in obstetric practice for predicting the success of labor induction and guiding management decisions.
Although modern imaging and biochemical tests can supplement it, Bishop’s Score continues to hold its place as the gold standard for assessing cervical favorability in pregnancy.
By understanding and applying the Bishop’s Score correctly, healthcare professionals can enhance maternal care, minimize complications, and improve overall birth outcomes.
FAQs
1. What is the purpose of Bishop’s Score?
The Bishop’s Score is used to assess the readiness of the cervix for labor and to predict the likelihood of successful induction of labor.
2. What is a normal Bishop’s Score for labor induction?
A score of 8 or more indicates that the cervix is favorable and induction is likely to be successful.
3. Who developed the Bishop’s Score?
Dr. Edward H. Bishop developed the scoring system in 1964.
4. What happens if the Bishop’s Score is low?
If the score is low (<5), cervical ripening methods like prostaglandins or mechanical dilators are used before labor induction.
5. Can Bishop’s Score predict spontaneous labor?
Yes. A higher Bishop’s Score increases the likelihood of spontaneous onset of labor.
6. Is Bishop’s Score applicable to both first-time and multiparous mothers?
Yes, though the probability of successful induction tends to be higher in multiparous women.
7. What are the limitations of Bishop’s Score?
It can be subjective, depends on examiner experience, and does not include modern predictive factors like cervical length by ultrasound.