The Bishop score is a system used by medical professionals to decide how likely it is that you will go into labor soon. They use it to determine whether they should recommend induction, and how likely it is that an induction will result in a vaginal birth.
The score considers different factors about your cervix and the position of your baby. Each factor is given a grade, and then these grades are added up to give you an overall score. It’s called the Bishop score because it was developed by Dr. Edward Bishop in the 1960s.
Understanding your score
There are several factors that your doctor will consider when calculating your score:
- Dilation of the cervix. This means how far your cervix has opened in centimeters.
- Effacement of the cervix. This means how thin your cervix is. It is normally about 3 centimeters long. It gradually becomes thinner as labor progresses.
- Consistency of the cervix. This means whether your cervix feels soft or firm. Women who have had previous pregnancies usually have a softer cervix. The cervix softens before labor.
- Position of the cervix. As the baby descends into the pelvis, the cervix — the doorway to the uterus — moves forward with the head and the uterus.
- Fetal station. This is how far up the birth canal the baby’s head is. Usually, before labor begins, the baby’s head moves from –5 (high up and not yet in the pelvis) to station 0 (where the baby’s head is firmly in the pelvis). During labor the baby moves through the vaginal canal until the head is clearly visible (+5) and the baby is about to be delivered.
Your doctor calculates your scores through a physical exam and ultrasound. Your cervix can be examined through a digital exam. The location of your baby’s head can be seen on an ultrasound.
If your Bishop score is high, it means that there’s a greater chance that an induction will be successful for you. If your score is 8 or above, it’s a good indication that spontaneous labor would start soon. If an induction becomes necessary, it’s likely to be successful.
If your score is between 6 and 7, then it’s unlikely that labor will be starting soon. An induction may or may not be successful.
If your score is 5 or below, it means that labor is even less likely to start spontaneously soon and an induction is unlikely to be successful for you.
Your doctor might suggest an induction to you. The most common reason for induction of labor is that your pregnancy has gone past your estimated due date. A normal maternal gestation is anywhere from 37–42 weeks. Research has shown that women should wait until 40 weeks to deliver unless there’s a complication. After 40 weeks, you might be induced. Some risks increase for both mother and baby after 42 weeks. Your healthcare provider may recommend induction after 42 weeks to reduce these risks.
Your doctor may also recommend induction if:
- you have gestational diabetes
- growth scans predict your baby will be large for its gestational age
- you have a pre-existing health condition that could affect your health if your pregnancy continues
- you develop preeclampsia
- your baby isn’t thriving as they should in utero
- your water breaks and contractions don’t start within 24 hours
- your baby has a diagnosed congenital condition that will require intervention or special care at birth
Induction is a medical procedure. It’s far better for the body to allow natural delivery without medical intervention. Pregnancy is a natural process, not a medical condition. You will want to avoid induction unless there’s a clear reason why you or the baby need it.
How is labor induced?
There are several different methods that medical professionals can use to induce labor.
Sweep your membranes
Before offering medical induction, your doctor or midwife may offer to sweep your membranes. During this procedure, your healthcare provider inserts their finger into your vagina and through your cervix if they find that it’s already slightly open. They manually separate the amniotic sac from the lower part of your uterus, which is thought to cause the release of prostaglandins. The release of prostaglandins may ripen your cervix and possibly get your contractions going.
Some women find sweeps extremely uncomfortable. There’s an increased risk of infection and there is no evidence that they are effective. There’s also a risk that the water can break. Delivery should occur within about 24 hours of the water breaking to prevent infection.
The typical next step in the induction process is to have synthetic prostaglandins inserted into your vagina in the form of a pessary or gel. These act like hormones and can help your cervix dilate and efface, which might bring on labor.
Artificial rupture of the membranes
If your cervix is ready for labor, your healthcare provider may offer to rupture your membranes. This involves using a small hooked instrument to break your amniotic sac. Sometimes this alone can be enough to start your contractions, meaning you wouldn’t need to progress to the next stage of induction.
There is an increased risk of infection, placental abruption, and umbilical prolapse. As with any procedure, you’ll need to weigh the risks and benefits with your healthcare providers and assess whether it’s the right course of action for you.
Synthetic oxytocin (Pitocin)
This will be used when all other methods have failed or aren’t suitable for you. It involves giving you synthetic oxytocin through an IV pump. Oxytocin is the natural hormone that your body produces during labor to stimulate contractions.
In most cases, women may need between 6 and 12 hours on a Pitocin drip to enter active labor. Usually, the drip will be started on the lowest dose and increased gradually until your contractions become regular. Contractions on a Pitocin drip are usually stronger and more painful than they would be naturally. There is no gentle build up to the contraction peak like you would get in a labor that started spontaneously. Instead, these contractions hit hard right at the beginning.
Risks of induction
The risk of further interventions increases when you’re induced. These interventions include:
- assisted deliveries
- cesarean delivery
There’s also a risk of causing stress to your baby because of the intensity and length of the contractions. In rare cases, there’s a risk of placental abruption or uterine rupture.
Your healthcare provider will only suggest induction if they believe waiting for labor to start would be riskier than intervening. Ultimately it’s your decision what course of action to take.
Tips for promoting labor and preventing induction
Stress is a known inhibitor of oxytocin release. If you want your labor to start naturally, one of the best things you can do is to fully relax. Pamper yourself, avoid known stressors, and allow your hormones to flow.
Exercise may help get your baby into the optimum position for labor, which will allow them to put the desired pressure on your cervix. Staying active and maintaining a healthy diet throughout your pregnancy are great ways to avoid developing gestational diabetes, which is a known risk factor in the induction of labor.
There are several methods you can try to naturally induce your labor, but there’s little scientific data to support the efficacy of these methods. An alternative to induction could be expectant management, which is where you go into the hospital regularly for monitoring to assess your baby’s condition.
Your Bishop score can help you and your healthcare provider understand your labor progression. Your score may also be used to help determine whether you are a good candidate for labor induction.
If your labor doesn’t start spontaneously before 42 weeks, then there are risks involved both in waiting for labor to start and in having your labor medically induced. Your healthcare provider should be able to provide you with all the evidence you need to weigh the risks and benefits and make an informed decision about what is right for you and your baby.