What is the Bishop Score?

The Bishop score consists of 5 parameters which are assessed with a vaginal examination. Calculating the ‘Bishop score’ will help you decide your chances of having a vaginal delivery, especially when labor is being induced.

SignPointsScore
0123
Position 
Consistency 
Effacement
Dilation
Fetal station
Results The Bishop Score is:
  • Using the ‘Bishop score’ will help you decide your chances of having a vaginal delivery, especially for induction. Five parameters are assessed.

A Bishop score can have a maximum of 13 and a score of 8 and higher increases your chances of having a successful induction and vaginal delivery. 

The American College of Obstetricians and Gynecologists says that… The goal of induction of labor is to achieve vaginal delivery by stimulating uterine contractions before the spontaneous onset of labor.

How can you predict if induction will be successful?

The best way to predict whether the induction is going to be successful and if you are going to have a normal delivery is to do a vaginal examination and check the cervix for 5 different parameters. Doing the ‘Bishop score’ will help determine your chances of having a vaginal delivery.

In most women labor begins spontaneously without anyone having to do something about it. But sometimes there are reasons why the baby should be delivered earlier before your labor begins by itself. Following are some reasons to induce labor: 

  • Abnormal fetal evaluation (e.g. intrauterine growth, low amniotic fluid)
  • Preeclampsia, Eclampsia
  • Medical conditions of the mother (e.g. diabetes, kidney disease, lung disease. chronic hypertension)
  • Rupture of fetal membranes at term
  • Infection of the placenta or fetus
  • Postdate pregnancy
  • Fetal demise
  • Abruptio placentae

Contrary to an ‘indicated induction’ an ‘elective induction’ is the induction of labor without any of these indications, but for either the woman’s or the doctor’s convenience.

How does a doctor decide to induce labor?

Before deciding how to induce labor, your doctor will do a vaginal examination with her fingers (digital examination) and check to see if you are getting ready for labor and delivery. The cervical examination checks to see if the cervix is soft, shortened, what it’s position is and if it’s opening up and how low the fetus is in the pelvis. From this examination, your doctor can then add up five factors which make up the ‘Bishop score’ to see which method to use and what the success of induction might be.

Cervix

Score

 

0

1

2

3

Position

Posterior

Midposition

Anterior

 

Dilatation

Closed

1-2 cm

3-4 cm

5-6cm

Consistency

Firm

Medium

Soft

 

Effacement

0-30%

40-50%

60-70%

>80%

Fetal station

-3

-2

-1,0

+1,+2

For example, the Bishop score is 6 when the cervix is 1-2 cm dilated (score of 1), the position is anterior (score of 2), it’s medium consistency (score of 1), the station is –3 (score of 0) and the cervix is 60-70% effaced (score of 2).

In general, a Bishop score above 8 has an excellent chance of vaginal delivery, but the most specific finding in the Bishop score is the dilatation of the cervix. Vaginal delivery is best predicted if the cervix is already dilated.

Methods of Induction

There are several ways to induce labor. Which one your doctor suggests depends on several factors such as how ready your cervix is and how much time is left in your pregnancy.

  1. Cervical dilators and administration of synthetic prostaglandin E1 (PGE1) and prostaglandin E2 (PGE2) are often used when the cervix is not ready yet for induction (low Bishop score). Your doctor may place prostaglandin medication into your vagina near the cervix to soften the cervix. This medication is usually left in place for 4-12 hours and the procedure is usually done in the hospital.
  2. Stripping the amniotic membranes is commonly practiced to induce labor, but it requires that the cervix is somewhat opened. It’s often done in the doctor’s office by placing a finger inside the cervix and sweeping the finger in a circular motion between the cervix and the fetal membranes. Many women feel that this is a painful procedure. Some studies have shown that more women went into labor after stripping membranes when compared to no intervention.
  3. Artificial rupture of the membranes may be used as a method of labor induction, especially if the condition of the cervix is favorable. This is done in the hospital by using a finger to separate your cervix and using a special instrument with a small hook at the end to break the membranes. You don’t really feel the rupture of membranes and this procedure is usually not more uncomfortable than a vaginal examination.
  4. Having sex has been suggested as an alternative for inducing labor. The prostaglandin in the ejaculate supposedly helps to soften the cervix.
  5. Another alternative method is the use of castor oil: 
    a. Blend 2-4 ounces of castor oil (3-4 Tablespoons) with just enough citrus juice (cuts the oil) to make it liquid.
    b. Have another glass of fresh juice, as well as a washcloth drenched with hot water, at hand. 
    c. Drink the castor oil mixture as quickly as possible and wipe out the mouth with the cloth and rinse the mouth to remove the oily residue. 
    Important: Stay close to a bathroom, the castor oil usually causes the bowels to empty within three hours.
  6. The most frequently used method of induction of labor is the use of oxytocin or Pitocin, a synthetic hormone which occurs naturally in your body when you go into labor.

How does Pitocin work?

Pitocin is given in the hospital usually in a slow intravenous drip, starting at a low dose and gradually increased until you are in labor and have regular contractions. One risk is that the medicine might not work. If labor won't start with medicine, and delivery is necessary, you might need to have a cesarean section

The major side effect of Pitocin is ‘hyperstimulation’, inducing contractions that are either too strong, last too long, or come to frequent. Hyperstimulation of the uterus can lead to abnormalities of the fetal heart rate, therefore the fetus’ heartbeat and the contractions have to be monitored closely by electronic fetal monitoring while you get Pitocin.

Often your own natural contraction mechanism will take over after induction with Pitocin the amount of Pitocin can be decreased, or Pitocin can be stopped altogether.

Contraindications to labor induction are usually the same as contraindications for spontaneous labor and delivery and include placenta previa or vasa previa, transverse fetal lie, prolapsed umbilical cord, and prior classical uterine incision

Some women say that labor is somewhat harder with pitocin induction than with spontaneous labor, but there are different opinions about it. Let your doctor or midwife know if your need pain medication such as an epidural anesthesia to minimize the discomfort of labor pains.

Questions to Ask Before Induction

Finally, make sure you understand why labor is being induced. When your doctor or midwife suggests that labor should be induced, ask the following questions:

1) What are the reasons for induction of labor?

2) How is the induction being done?

3) What are the benefits of induction?

4) What are the risks of induction of labor?

5) Is my fetus being monitored appropriately and how?

6) What is the anticipated success rate and is my cervix ready?

7) Can I first try an alternative method (e.g. castor oil, making love)