Introduction

The Bishop score is a widely used measure in obstetrics to assess the readiness of a pregnant woman’s cervix for labor and aid in predicting the likelihood of a successful induction. The score is derived from five parameters that contribute to cervical ripening and labor readiness. In this article, we will examine these parameters, demonstrate how to calculate the Bishop score, and discuss its clinical significance.

The Parameters

1. Cervical dilation: Measured in centimeters (cm), cervical dilation refers to the opening of the cervix, ranging from 0 cm (closed) to 10 cm (fully dilated).

2. Cervical effacement: Measured as a percentage, it evaluates how thin and shortened the cervix has become when comparing its original length.

3. Cervical consistency: Assessed by touch during a vaginal examination, it is described as firm, medium, or soft.

4. Cervical position: Refers to the location and angle of the cervix during an examination, classified as either posterior, intermediate, or anterior.

5. Fetal station: This parameter gauges how far the baby’s head has descended into the pelvis compared to the ischial spines. It is represented by negative numbers for higher positions and positive numbers for progressively lower positions.

Calculating the Bishop Score

Each of these parameters is given a numeric value based on set criteria:

1. Cervical dilation:

– 0 cm = 0 points

– 1-2 cm = 1 point

– 3-4 cm = 2 points

– ≥5 cm = 3 points

2. Cervical effacement:

– 0-30% = 0 points

– 40-50% = 1 point

– 60-70% = 2 points

– ≥80% = 3 points

3. Cervical consistency:

– Firm = 0 points

– Medium = 1 point

– Soft = 2 points

4. Cervical position:

– Posterior = 0 points

– Intermediate = 1 point

– Anterior = 2 points

5. Fetal station:

– -3 (above ischial spines) = 0 points

– -2 = 1 point

– -1, 0, or +1 (level with or below ischial spines) = 2 points

To calculate the Bishop score, you add up the points assigned for each parameter.

The Clinical Significance of the Bishop Score

A high Bishop score (≥8) indicates favorable conditions for a successful vaginal delivery and the lower the likelihood of requiring a cesarean section. A low Bishop score (<6) suggests that cervical ripening or induction methods may be needed before labor induction to improve the chances of a successful vaginal delivery.

Conclusion

The Bishop score is a valuable tool for clinicians when anticipating labor outcomes and planning inductions. By considering various factors such as cervical dilation, effacement, consistency, position, and fetal station, healthcare professionals can make informed decisions concerning the best course of action for pregnant women and their babies.