What Is the Bishop Score?
The Bishop Score is a widely used tool in obstetrics that helps assess how prepared a pregnant woman’s body is for labor and delivery. Developed by Dr. Edward Bishop in 1964, this scoring system evaluates specific physical characteristics of the cervix and the baby's position in the pelvis. It is typically used by healthcare providers late in pregnancy, especially when considering whether to induce labor.
The Bishop Score includes five key components observed during a pelvic exam:
- Cervical dilation – Measures how open the cervix is, from completely closed (0 cm) to 5 cm or more.
- Cervical effacement – Describes how thin or short the cervix has become in preparation for childbirth, expressed as a percentage.
- Cervical consistency – Refers to how firm, medium, or soft the cervix feels when examined.
- Cervical position – Indicates whether the cervix is positioned posteriorly (toward the back), mid-position, or anteriorly (toward the front) in the birth canal.
- Fetal station (head height) – Describes the position of the baby's head in relation to the ischial spines of the pelvis. A lower or engaged position is more favorable for delivery.
Each of these elements is given a score ranging from 0 to 2 or 3, and the total is calculated to give an overall Bishop Score between 0 and 13. The higher the score, the more favorable the cervix is for labor:
- Score 8–13: Indicates that the body is ready for labor, and induction (if needed) is likely to be successful.
- Score 5–7: Considered moderately favorable; labor may begin soon, but induction success varies.
- Score below 5: Suggests that the cervix is not yet ready, and induction might be less successful without additional medical assistance.
Healthcare providers use the Bishop Score as a guide when deciding whether to induce labor, especially in pregnancies approaching or past the due date. It is a helpful clinical tool, but it’s important to remember that the score is only one part of the overall assessment. Factors such as the baby's health, the mother's condition, and pregnancy history are also considered before making decisions about labor and delivery.
Ultimately, the Bishop Score offers a standardized and simple method for evaluating labor readiness, helping support safer and more informed medical decisions.
Why Is It Important?
The Bishop Score plays a crucial role in guiding decisions about labor and delivery. It is especially important when healthcare providers are considering whether or not to induce labor. By providing an objective way to assess the readiness of the cervix and the position of the baby, the score helps ensure that induction is done at the right time and in the safest way possible for both the mother and the baby.
Here are several reasons why the Bishop Score is important:
- Predicts Success of Labor Induction: A higher Bishop Score is strongly associated with a higher chance of successful vaginal delivery following induction. A low score may indicate that the body is not yet ready, which could increase the likelihood of a longer labor or the need for a cesarean section.
- Reduces Unnecessary Interventions: Knowing whether the cervix is favorable for labor can prevent unnecessary medical interventions or complications that might arise from inducing labor too early.
- Improves Safety for Mother and Baby: The Bishop Score helps healthcare providers evaluate the safest time to initiate labor, reducing risks associated with failed induction, prolonged labor, or emergency delivery.
- Supports Clinical Decision-Making: It gives doctors a structured, evidence-based method to make informed decisions about when to admit a patient, whether to wait, or whether to proceed with medical induction.
- Provides Peace of Mind: For expectant mothers, understanding their Bishop Score can offer reassurance and clarity about the delivery process, especially when approaching or passing their due date.
How the Bishop Score Is Calculated
The Bishop Score is calculated based on five physical factors observed during a pelvic exam. Each factor is given a numerical value depending on its condition, and the total score helps determine how ready the cervix is for labor. The five components are:
- Cervical Dilation: Measures how open the cervix is.
- 0 cm (closed) – 0 points
- 1–2 cm – 1 point
- 3–4 cm – 2 points
- 5 cm or more – 3 points
- Cervical Effacement: Refers to how thin the cervix has become.
- 0–30% (long) – 0 points
- 40–50% – 1 point
- 60–70% (short) – 2 points
- 80% or more (fully effaced) – 3 points
- Cervical Consistency: Assesses the firmness of the cervix.
- Firm – 0 points
- Medium – 1 point
- Soft – 2 points
- Cervical Position: Describes where the cervix is located in the birth canal.
- Posterior (toward the back) – 0 points
- Mid-position – 1 point
- Anterior (toward the front) – 2 points
- Fetal Station (Head Height): Indicates how far the baby’s head has descended into the pelvis.
- –3 station (high and mobile) – 0 points
- –2 station (primed) – 1 point
- –1 or 0 station (fixed or just above) – 2 points
- +1 or +2 station (engaged) – 3 points
Each category is scored individually, and the total score is the sum of all five values. The maximum possible score is 13. A higher score means the cervix is more favorable for labor:
- 8–13 points: Highly favorable – spontaneous labor or successful induction is likely.
- 5–7 points: Moderately favorable – labor may begin naturally, but induction outcomes vary.
- 0–4 points: Unfavorable – cervix is not ready, and induction may be less effective.
Breakdown of Each Factor
To better understand how the Bishop Score works, it’s helpful to look at each of the five components individually. These clinical factors reflect the physical changes in a woman’s body as it prepares for labor.
Cervical Dilation
This measures how open the cervix is. Dilation is measured in centimeters, ranging from 0 cm (closed) to 10 cm (fully dilated for childbirth). For the Bishop Score:
- 0 cm (Closed): 0 points
- 1–2 cm: 1 point
- 3–4 cm: 2 points
- 5 cm or more: 3 points
Cervical Effacement
Effacement refers to the thinning and shortening of the cervix in preparation for labor. It is usually described as a percentage:
- 0–30% (Long): 0 points
- 40–50% (Half-length): 1 point
- 60–70% (Short): 2 points
- 80% or more (Effaced): 3 points
Cervical Consistency
This describes how soft or firm the cervix feels during examination. A softer cervix is a sign that the body is preparing for labor:
- Firm: 0 points
- Medium: 1 point
- Soft: 2 points
Cervical Position
As labor approaches, the cervix moves from a posterior position (toward the back) to an anterior position (toward the front), making it easier for the baby to pass through:
- Posterior: 0 points
- Mid-position: 1 point
- Anterior: 2 points
Fetal Head Station
Also known as the "fetal station," this indicates how far the baby’s head has descended into the mother’s pelvis. It is measured relative to the ischial spines (bony landmarks inside the pelvis):
- –3 station (High and mobile): 0 points
- –2 station (Primed): 1 point
- –1 or 0 station (Fixed): 2 points
- +1 or +2 station (Engaged): 3 points
Each of these factors is assigned a score based on its current state, and the total Bishop Score helps determine whether labor is likely to begin naturally or if medical induction is needed.
How to Use the Bishop Score Calculator
The Bishop Score Calculator is a helpful tool that allows expectant mothers and healthcare providers to quickly determine how ready the cervix is for labor. It simplifies the process by turning clinical findings from a pelvic exam into a clear numerical score. Here’s a step-by-step guide on how to use it:
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Access the Calculator: Open the Bishop Score Calculator on your device. It typically includes a form with selectable options for each factor.
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Select Cervical Dilation: Choose the option that best matches how open the cervix is (e.g., closed, 1–2 cm, 3–4 cm, or 5 cm or more).
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Select Cervical Effacement: Pick the percentage that reflects how thin or short the cervix is (e.g., 0–30%, 40–50%, 60–70%, or 80%+).
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Select Cervical Consistency: Select whether the cervix is firm, medium, or soft to the touch.
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Select Cervical Position: Choose the cervix’s position in the vaginal canal: posterior, mid, or anterior.
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Select Fetal Head Station: Choose the position of the baby's head relative to the pelvis (e.g., high and mobile, primed, fixed, or engaged).
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Click "Calculate": Once you’ve selected an option for each category, click the “Calculate” button. The calculator will instantly total the score.
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Review the Result: The score will appear in the result box. Compare your score to the interpretation ranges to see how favorable your cervix is for labor.
Interpreting the Score
Once you calculate your Bishop Score, the number gives you a general idea of how ready your body is for labor. The score ranges from 0 to 13, with higher numbers indicating a greater likelihood that labor will start on its own or that an induction will be successful.
Here’s how to interpret the total score:
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0–4 points:
This score suggests that the cervix is not yet ready for labor. Inducing labor at this stage may not be effective and could increase the risk of a long labor or the need for a cesarean section. In most cases, healthcare providers may choose to wait or use medications to help soften the cervix before trying induction.
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5–7 points:
This is a moderately favorable score. It indicates that the cervix is beginning to prepare for labor, but there is still some uncertainty. Labor may begin soon, and induction could be successful, especially with the help of certain medications or procedures.
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8–13 points:
A score in this range means the cervix is favorable for labor. This is considered a good time for induction if needed, and spontaneous labor is likely to begin soon on its own. Most patients with this score can expect a smoother and more successful labor process.
It's important to remember that while the Bishop Score is a valuable tool, it is just one part of the overall assessment. Your healthcare provider will also consider your baby's health, your medical history, and how far along you are in your pregnancy when making decisions about labor and delivery.
When Should This Calculator Be Used?
The Bishop Score Calculator is most commonly used in the final weeks of pregnancy, especially when there is a need to evaluate whether labor is likely to start on its own or if medical induction should be considered. It helps healthcare providers assess cervical readiness in a structured way.
Here are the most common situations where this calculator is used:
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Before Labor Induction:
If your doctor is considering inducing labor, they may use the Bishop Score to decide whether your cervix is favorable. A higher score means a higher chance of a successful vaginal delivery following induction.
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Post-Term Pregnancy:
If you’ve passed your due date, the Bishop Score can help determine if it’s safe and timely to induce labor or if more time should be allowed for natural labor to begin.
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High-Risk Pregnancies:
In cases where medical conditions like gestational diabetes, high blood pressure, or fetal growth concerns exist, the calculator can help plan safe delivery timing.
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Before a Scheduled Delivery:
Some doctors may check the Bishop Score in preparation for a planned delivery to ensure that the cervix is ready and reduce the chances of complications.
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Monitoring Labor Progress:
In early labor, the Bishop Score may also be used to evaluate how well the body is progressing toward delivery.
Limitations and Considerations
While the Bishop Score is a helpful tool for assessing labor readiness, it's important to understand that it has limitations. It is not a guaranteed predictor of when labor will begin or how successful an induction will be. Instead, it offers a general guide based on physical signs observed during a pelvic exam.
Here are a few important considerations to keep in mind:
- Subjective Interpretation: The score depends on a physical exam, which can vary slightly depending on the provider's experience and technique.
- Does Not Predict All Outcomes: A high score does not guarantee a fast or easy labor, and a low score does not mean labor will be unsuccessful. Every pregnancy is unique.
- Only One Part of the Assessment: The Bishop Score does not account for other health factors, such as the baby's well-being, the mother's medical history, or complications that may affect delivery.
- Time-Sensitive: The cervix can change quickly in late pregnancy, so a Bishop Score today may not be the same tomorrow.
For these reasons, the Bishop Score should always be considered alongside other medical assessments and discussed with a healthcare provider.
Frequently Asked Questions (FAQs)
What is a good Bishop Score for induction?
A score of 8 or more is generally considered favorable for labor induction. It means the cervix is likely ready, and induction has a good chance of success.
Can the Bishop Score change over time?
Yes. The cervix can soften, dilate, or shift position in a matter of hours or days. That’s why the score can improve naturally as labor approaches.
Is the Bishop Score painful to check?
The score is determined through a pelvic exam, which may cause mild discomfort, but it is usually quick and tolerable.
Can I check my own Bishop Score at home?
No. It requires a trained healthcare provider to perform a safe and accurate pelvic exam. Self-assessment is not recommended.
Does a low score mean I’ll need a C-section?
Not necessarily. A low Bishop Score may mean induction could take longer or require additional support, but it does not automatically lead to a cesarean delivery.
Disclaimer
The Bishop Score Calculator is a supportive tool designed for informational purposes only. It does not replace a professional medical evaluation or advice. Only a licensed healthcare provider can assess your condition accurately and determine the best course of action for you and your baby.
Always consult your doctor or midwife before making any decisions about labor and delivery based on your Bishop Score.
References
- Bishop, E. H. (1964). *Pelvic scoring for elective induction*. Obstetrics & Gynecology, 24(2), 266–268.
- Gabbe, S. G., Niebyl, J. R., & Simpson, J. L. (2016). Obstetrics: Normal and Problem Pregnancies (7th ed.). Elsevier.
- Cunningham, F. G., Leveno, K. J., Bloom, S. L., Spong, C. Y., & Dashe, J. S. (2018). Williams Obstetrics (25th ed.). McGraw-Hill Education.
- American College of Obstetricians and Gynecologists (ACOG). (2022). Induction of Labor: Practice Bulletin No. 107.
- Moore, T. R., & Reiter, R. C. (2019). Maternal-Fetal Medicine: Principles and Practice (8th ed.). Saunders.