Everything You Need Know About Labor Induction

Labor Induction

What is labor induction?

Labor induction is using medications to start (induce) labor with the goal of achieving a vaginal delivery. Inductions can be done electively after 39 weeks or for medical reasons such as high blood pressure, diabetes, fetal growth restriction, or going too far past the due date. 

How is labor induced?

The first step is for a provider to check the cervix to determine the Bishop score. A score less than 6 means the cervix needs ripening. A score of 8 or greater means that if oxytocin is started there is the same chance of a vaginal delivery as if labor began spontaneously.

How is the Bishop score determined?

This score is determined based on dilation, effacement, station, consistency and position. The points for each category are added together to get the Bishop Score.

Cervical Exam 0 points 1 points 2 points 3 points
Dilation (cm) Closed 1-2cm 3-4cm 5-6cm
Effacement (%) 0-30% 40-50% 60-70% 80% +
Station -3 -3 -1, 0 +1, +2
Consistency Firm Medium Soft  
Position Posterior Mid Anterior  


What happens if the Bishop score is less than 6?

In this case cervical ripening is required. It can be done with medicines known as prostaglandins which help soften and thin the cervix. Cervidil contains prostaglandins in a small tab connected to a string. It is placed just behind the cervix and slowly releases prostaglandins for 12 hours before being removed. Misoprostol contains prostaglandins in a tablet. A piece of this tablet is placed behind the cervix or between the cheek and gums where it dissolves. Although the tablet may have dissolved, it continues to soften and thin the cervix for 4 hours. Multiple doses of Cervidil and misoprostol can be used. Prostaglandins cannot be used to ripen the cervix of a woman who has had a prior cesarean section. 

What happens when the Bishop score is greater than 6?

Once the cervix is ready, a Bishop score of 6-8, oxytocin can be used to create regular uterine contractions. Oxytocin is a hormone that is produced naturally by the brain to cause uterine contractions. A synthetic form is available and given through an IV so the dose can be increased or decreased based on the frequency and strength of contractions as well as how well the baby tolerates contractions. 

What other methods can be used to induce labor?

What are the risks associated with labor induction?

Because medications are being used to cause uterine contractions there is the risk that too many contractions can occur which can cause stress to the baby and increases the risk of uterine rupture. If too many contractions are occurring because of oxytocin, the oxytocin can be decreased or turned off. If Cervidil is being used it can be removed early by pulling gently on the string. Misoprostol unfortunately cannot be removed or washed out once it has dissolved. Terbutaline is an injection that can be given to help relax the uterus and stop contractions. 

Just as with spontaneous labor, induction of labor is not always successful and some women require cesarean sections. Using the Bishop score and waiting to use Oxytocin until the Bishop score is 8 helps decrease the risk of induction failure. The most common reason for a cesarean section in the United States is fetal intolerance of contractions or non-reassuring fetal heart rate and this may occur at any stage of labor be it an induction or spontaneous. If you have questions or concerns regarding labor induction please discuss them with your health care provider. 

Dr. Gottschalk Dr. Kathryn Gottschalk OBGYN

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