The Bishop Score is a pre-labor scoring system that helps to evaluate the readiness of the cervix for labor. It is often used to determine whether induction of labor is necessary. The score is based on five factors, each of which is assessed and given a score. These factors are:

1. Dilation (cm)

• Definition: This measures how much the cervix has opened in preparation for childbirth.
• Values:
  • 0 cm (Score: 0): The cervix is completely closed.
  • 1-2 cm (Score: 1): The cervix has begun to open slightly.
  • 3-4 cm (Score: 2): The cervix is moderately open.
  • ≥ 5 cm (Score: 3): The cervix is significantly open, indicating that labor is likely imminent.

Learn more about cervical dilation from here and here.

2. Effacement (%)

• Definition: Effacement refers to the thinning of the cervix, expressed as a percentage of how thin the cervix has become compared to its normal thickness.
• Values:
  • 0-30% (Score: 0): The cervix has thinned only slightly.
  • 40-50% (Score: 1): The cervix has thinned about halfway.
  • 60-70% (Score: 2): The cervix is mostly thinned.
  • ≥ 80% (Score: 3): The cervix is very thin, indicating readiness for labor.

Learn more from here and here.

3. Station

• Definition: Station describes the position of the baby’s head in relation to the ischial spines of the pelvis, which are bony landmarks. It is a measure of how far the baby has descended into the pelvis.
• Values:
  • -3 (Score: 0): The baby’s head is high in the pelvis.
  • -2 (Score: 1): The head is slightly lower but still above the ischial spines.
  • -1, 0 (Score: 2): The head is level with the ischial spines, indicating it is well engaged in the pelvis.
  • +1, +2 (Score: 3): The head is below the ischial spines, indicating the baby is very close to delivery.

Learn more here.

4. Cervical Consistency

• Definition: This assesses the firmness of the cervix. As labor approaches, the cervix typically softens.
• Values:
  • Firm (Score: 0): The cervix is still hard and not ready for labor.
  • Medium (Score: 1): The cervix is starting to soften.
  • Soft (Score: 2): The cervix is soft, indicating that labor is near.

Learn more from here and here.

5. Cervical Position

• Definition: This refers to the position of the cervix in relation to the vaginal canal. The cervix typically moves from a posterior (back) position to an anterior (front) position as labor approaches.
• Values:
  • Posterior (Score: 0): The cervix is positioned towards the back, away from the vaginal canal.
  • Mid-position (Score: 1): The cervix is moving forward.
  • Anterior (Score: 2): The cervix is positioned towards the front, aligning with the vaginal canal, which is favorable for labor.

Learn more here.

Reference

1. Rosli AA, Nawi AM, Atan IK, Kalok AM, Ahmad S, Ismail NAM, Mahdy ZA, Rahman RA. Cervical dilatation at diagnosis of active phase of labour determines the mode of delivery and peripartum outcomes: a retrospective study in a single tertiary centre in Malaysia. BMC Pregnancy Childbirth. 2023 Apr 1;23(1):221. doi: 10.1186/s12884-023-05523-7. PMID: 37005571; PMCID: PMC10067294.
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