Bishop Score Test: Purpose, Test Details & Results

The Bishop Score remains a cornerstone in obstetric care—especially when it comes to predicting how ready a pregnant person’s cervix is for labor induction. Despite being designed decades ago, it continues to shape clinical decisions, yet modern research reveals both strengths and limitations. In this article, we’ll guide you through the purpose of the Bishop Score test, how it works, what the results mean, and what to expect after the test.

Purpose of Bishop Score Test

Assessing whether the cervix is “ready” for labor is a key step before inducing labor. The Bishop Score helps healthcare providers estimate the likelihood that labor induction will lead to a vaginal delivery. While originally intended as a selection tool for certain patients, its use has expanded widely—sometimes beyond its original design.

Why the Bishop Score Exists

The Bishop Score was created to provide a simple, bedside tool for evaluating the cervix before labor induction. The idea: if the cervix is favorable—meaning soft, dilated, and thinning—labor induction is more likely to succeed. If it’s not, alternative approaches or additional cervical ripening may be needed 1, 2, 5.

Clinical Applications

In practice, the Bishop Score is used to:

• Decide whether to proceed with induction or wait
• Choose appropriate cervical ripening methods (medications versus mechanical)
• Counsel patients on their likelihood of a vaginal delivery
• Identify women who might need closer monitoring during induction 1, 2, 4

Limitations and Evolving Perspectives

Despite its widespread use, the Bishop Score has limitations:

• Subjectivity: Different clinicians may assign different scores to the same patient 5, 6.
• Incomplete Predictive Power: It’s not always reliable for predicting successful induction, especially in first-time mothers or certain populations 3, 5.
• Omission of Variables: Important factors like parity, fetal position, or ultrasound findings are not included 5, 6.
• Original Purpose vs. Modern Use: It was originally intended for a narrow group but is now used broadly 5.

Recent research suggests that, while still the best clinical tool available, there is a need for more objective and comprehensive approaches—potentially including ultrasound parameters or biochemical markers 5, 6.

Bishop Score Test Details

The Bishop Score is a hands-on assessment performed during a vaginal examination. It quantifies five key features of the cervix and fetal station, providing a score that guides labor management.

How the Test Is Performed

The Bishop Score is determined during a vaginal examination, usually done in the hospital or clinic prior to labor induction:

• Cervical dilation: Measured in centimeters from closed (0) up to 10 cm (fully dilated). The Bishop Score awards up to 3 points.
• Effacement: Refers to the cervix thinning out; reported as a percentage or in centimeters. More effaced means a higher score.
• Station: Indicates how far the fetal head has descended into the pelvis (measured in relation to the ischial spines).
• Consistency: Describes whether the cervix feels firm, medium, or soft (softer is more favorable).
• Position: The cervix may point towards the back (posterior), middle, or front (anterior) of the vagina.

Each feature is assigned a number, and the total is summed. Scores range from 0 (very unfavorable) to 13 (very favorable) 1, 5.

Interpretation of the Score

• Low Score (≤5): Indicates an “unripe” or unfavorable cervix. Labor induction is less likely to result in vaginal delivery without further cervical ripening.
• Mid-Range Score (6–8): Intermediate chance of successful induction.
• High Score (≥9): Highly favorable for successful induction and vaginal birth 5.

Variations and Modifications

• Simplified Bishop Score: Some studies have tested simplified versions for easier bedside use, but these may sacrifice predictive accuracy 1, 4.
• Subjectivity and Reliability: Scoring may vary between clinicians. Research highlights moderate “kappa” values for inter-observer agreement (0.35–0.69), emphasizing the need for more objective alternatives 5, 6.
• Ultrasound and Biochemical Alternatives: Research is exploring the use of cervical length (ultrasound) or fetal fibronectin testing to improve accuracy, but these have not yet replaced the Bishop Score in routine practice 4, 6, 7.

Strengths and Weaknesses

Strengths:

• Fast, low-cost, and accessible
• Standardized framework available globally

Weaknesses:

• Operator-dependent and subjective
• May omit important predictive factors
• Moderate reliability and reproducibility 5, 6

Bishop Score Test Results & Follow-Up

The results of the Bishop Score test guide labor management and patient counseling. Understanding what your score means can help set expectations for the induction process.

What the Results Mean

• A high Bishop Score (≥9): Indicates a favorable cervix. Induction is likely to result in a vaginal delivery, often without the need for additional interventions 2, 5.
• A low Bishop Score (≤5): Suggests the cervix is not ready. Additional cervical ripening (medications or mechanical dilators) may be recommended before starting labor induction 2, 4, 5.
• Intermediate scores (6–8): May require individualized management and closer clinical judgment.

Predictive Value and Real-World Outcomes

• Meta-analyses show that higher Bishop Scores correlate with increased odds of successful vaginal delivery after induction (OR per unit increase ranges from 1.33 to 1.52) 2.
• Limitations: Some studies highlight that the Bishop Score, especially in nulliparous (first-time) mothers, may be a poor predictor of outcome, with sensitivity and specificity lower than ideal 3, 4. Its performance can also be less impressive in predicting failed inductions or cesarean deliveries 3.
• Ultrasound and Additional Markers: Incorporating cervical length by ultrasound or biochemical markers can improve predictive power but are not yet standard 4, 6, 7.

Follow-Up Steps

• If Score Is Low: The provider may recommend cervical ripening agents (prostaglandins, balloon catheters) before attempting labor induction 4, 5.
• If Score Is Favorable: Labor induction can proceed, often with oxytocin or amniotomy.
• Ongoing Assessment: The Bishop Score may be reassessed during labor if progress is slow, or if induction is not proceeding as expected 4, 5.
• Patient Counseling: Providers should discuss both the strengths and limitations of the Bishop Score, set realistic expectations, and consider patient preferences when planning induction.

Key Points for Patients

• The Bishop Score is just one part of the induction decision-making process.
• A low score does not mean vaginal delivery is impossible; it may just require more time or interventions.
• Regular monitoring and open communication with your healthcare provider are essential.

Conclusion

The Bishop Score remains the most widely used tool to assess cervical readiness and guide labor induction. However, it is not without its limitations and should be interpreted in the context of each patient’s unique situation.

Main Points Covered:

• The Bishop Score helps predict the likelihood of successful labor induction and vaginal delivery, guiding clinical decisions and patient counseling 1, 2, 5.
• It consists of five key clinical features: dilation, effacement, station, consistency, and position, scored during a vaginal exam 1, 5.
• While higher scores suggest a greater chance of vaginal delivery, the Bishop Score’s predictive accuracy is moderate and may vary by patient population 2, 3, 4.
• Limitations include subjectivity, omission of some predictive factors, and moderate inter-observer reliability 5, 6.
• Research is ongoing to find more objective and accurate approaches, including ultrasound and biochemical markers, but the Bishop Score remains the standard for now 4, 6, 7.
• Always discuss your Bishop Score and labor induction plan with your healthcare provider, considering both the benefits and limitations of the test.

By understanding the Bishop Score, patients and providers can work together to make informed decisions about labor induction and optimize outcomes for both parent and baby.