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Bishop Score Calculator

Created by Dominika Śmiałek, MD, PhD candidate
Reviewed by Dominik Czernia, PhD and Jack Bowater
Based on research by
Kelly C. Wormer; Amelia Bauer; Ann E. Williford. Bishop Score; Treasure Island (FL): StatPearls Publishing; last updated - September 2022
Last updated: Sep 28, 2023


This Bishop score calculator determines whether the body is ready for delivery, and if the induction of birth is possible.

We try our best to make our Omni Calculators as precise and reliable as possible. However, this tool can never replace a professional doctor's assessment. All information on this website is for informational purposes only and is not intended to serve as a substitute for medical consultation. Always consult your results with a health care provider.

Bishop score - briefly

The Bishop score estimates the preparedness of a woman's body for delivery. Of course, you may know the estimated due date, but that's only an estimate made with a due date calculator; you can only know if this is really the time shortly before labor.

This formula is based on five characteristics, three of which describe the cervix of the mother, and two that cover the baby's position within the womb. Points are assigned to each result, and the sum of all of the points is the Bishop score. It indicates whether there's a high probability of successful labor or, more importantly, if it can be induced.

What does induce mean when it comes to labor?

In some cases, gynecologist may decide to perform a labor induction. This means to cause the delivery, either by using drugs or non-medical measures. Why might labor be induced?

  1. Post-term pregnancy, lasting longer than 42 weeks. If twins: beyond 38 weeks. With every other baby, e.g., triplets, quadruplets, the safe duration of the pregnancy shortens. However, such big pregnancies tend to be a result of an in-vitro fertilization and are rare after a natural conception. Even in those cases, you can use the IVF due date calculator.
  2. Intrauterine fetal growth restriction (IUGR).
  3. Some conditions, such as pre-eclampsia, diabetes, or hypertension, which put the mother's or baby's health at risk.
  4. If the birth doesn't start naturally after a premature rupturing of membranes.
  5. Abortion.
  6. Overweight mother, which is why maintaining a healthy weight (calculate the correct weight gain with the pregnancy weight gain calculator) during pregnancy, is important.

Not all women can undergo elective induction. First, the pregnancy should be at least 36 weeks along. Younger babies are not mature enough to be born, and their delivery might lead to complications, lower results in an APGAR score calculator, and a spell in the ICU. Second is multiparity - if the woman has given birth before, then the whole process is more predictable for both the physician and the mother; the duration, pain, and any condition that might make a natural birth complicated.

There are many more indications and contraindications and the decision should be made by the health care provider and the pregnant patient.

What does induce mean in detail? Among the drugs used for the induction of delivery you'll find:

  • Intra-vaginal prostaglandins, such as misoprostol, which cause uterine contractions and effacement (thinning) of the cervix.
  • Intravenous oxytocin, a hormone that naturally induces labor.

There are also some non-pharmacological options, such as:

  • Membrane sweep, a short procedure where the midwife or obstetrician puts a finger into the cervix. With a circular movement, they try to separate the sac surrounding your baby from the cervix.
  • Artificial rupture of the membrane (amniotomy). However it's not conclusive yet whether or not an amniotomy alone facilitates the birth.

Station labor, cervical dilation, posterior position - a glossary

  • Cervical dilation - where the cervix opens up in preparation for birth. If you're not yet ready to give birth, then your cervix is not dilated at all. However, when the delivery is starting, dilation reaches up to 10 cm! While that may sound surprisingly big, this size is safe; it allows the baby's head to go through your vagina.

  • Cervical effacement - in non-medical words: the thinning of the cervix, often expressed as a percentage. During pregnancy, mucus closes the cervix. When the labor is about to begin, the mucus passes, and the cervix shortens and thins.

  • Cervical consistency - how the cervix feels, i.e., is it soft or firm. This is determined via a manual examination.

  • Station labor - how far down your baby has moved. There are three main cut-off points: the head is at the entrance to the canal, it is at the level of the ischial spines, and, finally, the head is just above the opening.

  1. Position - the cephalic presentation of the baby in the womb. Throughout the whole pregnancy, the baby moves from side to side, often changing its position and rolling over. If the fetus ends up in the breech position and can't flip around, the gynecologist may perform a c-section. However, the most common position is the cephalic position, which allows vaginal birth. You can estimate the chances of vaginal birth even after a c-section with the VBAC calculator.

There may be some differences in the position of the face:

  • In case it's towards the mother's back, we call it the anterior position
  • If the face of the baby is turned towards the side (either hip of the mother), it's called a mid-position
  • In case the baby's face looks towards the mother's front, it's called the posterior position. This makes it much harder for the baby to get through the pelvis, but sometimes it may happen that it will rotate during the birth.
Cephalic presentation - right occipitoposterior
By Mikael Häggström, used with permission (CC0 1.0, wikimedia.org

Bishop score calculator

In our tool, we focus on the signs that indicate whether induction could be successful. For each answer, you get a certain number of points, provided in the brackets:

  1. Cervical dilation in centimeters:
  • closed (0)
  • 1-2 cm (1)
  • 3-4 cm (2)
  • more than 5 cm (3)
  1. Cervical effacement as a percentage:
  • 0-30% (0)
  • 40-50% (1)
  • 60-70% (2)
  • more than 80% (3)
  1. Cervical consistency assessed by the gynecologist:
  • Firm (0)
  • Moderately firm (1)
  • Soft (2)
  1. Fetal station labor, the position of the fetal head with respect to the pelvic bones:
  • -3, the baby has not reached the vaginal canal (0)
  • -2 (1)
  • -1 or 0, the baby's head has reached the ischial spines (2)
  • +1 or +2, the baby's head is already at the end of the canal (3)
  1. Head position
  • Posterior position (0)
  • Mid-position (1)
  • Anterior position (2)

After assessing all of the five factors, sum up the points to get the Bishop score.

The interpretation of the Bishop score
If the score is six or below, the cervix is not ripe, and the chances of vaginal labour are low. If induction is inevitable, the doctor might apply some cervical ripening agents. On the other hand, if the score is eight or more, cervix is favourable and the chances of vaginal delivery after labor induction are similar to that after spontaneous labor.

Bishop score calculator in practice

Now that we're familiar with the theory let's practice it as an example. Cassy, a 32-year-old lawyer, is 37 weeks pregnant with her second kid. She's thrilled with the pregnancy and can't wait for the child to come! The problem is that she might need induction. However, is she eligible for a vaginal birth and a successful induction? What does induce mean in her case? Is there a recommended method? The gynecologist is not so sure and, after a physical examination, decides to use our Bishop score calculator to count her score.

  1. Cervix dilation is 6 cm (3)
  2. Cervical effacement is a bit more than 60% (2)
  3. The cervix is moderately firm (1)
  4. The baby's head has just reached the ischial spines (2)
  5. The baby is in mid-position (1)

The total score is 9, so according to the Bishop score interpretation, the cervix is favorable.

Dominika Śmiałek, MD, PhD candidate
Cervix
Dilation
in
Effacement
0-30%
Consistency
Firm
Baby
Fetal station
-1 or 0
Head position
Posterior
Result
Bishop score
Interpretation: the results are inconclusive.
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