In most women, labor induction is not necessary because labor begins spontaneously without anyone having to do something about it. But sometimes a baby needs to be delivered before labor begins by itself.

These are some reasons that might make your doctor decide to induce labor:

  • Abnormal fetal evaluation, such as intrauterine growth restriction, low amniotic fluid
  • Preeclampsia or eclampsia
  • Mother's medical conditions, including diabetes, kidney disease, lung disease, chronic hypertension
  • Premature rupture of fetal membranes 
  • Infection of the placenta or fetus
  • Postdate pregnancy
  • Fetal death
  • Abruptio placentae

"The goal of induction of labor," according to the American College of Obstetricians and Gynecologists, "is to achieve vaginal delivery by stimulating uterine contractions before the spontaneous onset of labor." An "indicated induction" is one that's done for medical reasons such as those listed above. An "elective induction" is done without any of these indications, but rather for the woman's or the doctor's convenience. There are several methods of inducing labor, which I'll get to shortly.

The best way to predict the success of an induction, and to decide which method to use, is to do a vaginal examination and check the cervix for five different parameters, which are added up to create a "Bishop score."

Your doctor will do a vaginal exam with her fingers to see if you're getting ready for labor and delivery. She'll check to see if your cervix is soft and shortened, what position it's in, if it's opening up, and how low the fetus is in the pelvis. She'll rank you on each factor and add up the numbers to get your Bishop score.

Bishop Score

  0 1 2 3  
Dilatation closed 1-2 cm 3-4 cm 5-6+ cm  
Consistency firm medium soft    
Position posterior mid anterior    
Effacement 0-30% 40-50% 60-70% >70%  
Fetal Station -3 -2 -1, 0 +1, +2  

In general, a Bishop score of 8 and above means there's an excellent chance you'll deliver vaginally, but the most specific predictor of successful vaginal delivery is dilatation of the cervix. If you're already dilated, your chances are better.

Depending on how much time you have and how ready your cervix is, your doctor may suggest one of the following methods of induction:

The most frequently used method is the administration of oxytocin or pitocin, synthetic versions of a natually occuring labor hormone. Pitocin is given in the hospital, starting with a low dose in a slow IV drip. The dose is gradually increased until you have regular contractions. If labor doesn't start and delivery is necessary, you might have to have a Caesarean section.

The major side effect of pitocin is uterine hyperstimulation -- inducing contractions that are too strong, last too long or come too frequently. Hyperstimulation can cause fetal heart rate abnormalities, so heart rate and contractions have to be monitored closely. Often, the natural contraction mechanism will take over after pitocin induction, and the amount can be decreased or stopped altogether.

When the cervix isn't yet ready for induction and you have a low Bishop score, your doctor may use cervical dilators and administer synthetic prostaglandin or prostaglandin in your vagina to soften the cervix. This medication is usually given in the hospital and left in place for four to 12 hours.

Stripping Fetal Membranes
If the cervix is somewhat open, your doctor may strip the amniotic membranes to induce labor. In a procedure that's usually done in the doctor's office -- and that many women find painful -- the physician sweeps a finger in a circular motion between the cervix and the fetal membranes. Studies have found that more women go into labor after their membranes are stripped than if no such intervention has taken place.

Rupture of Fetal Membranes
If the condition of the cervix is favorable, your doctor may artificially rupture the membranes. This procedure, which is done in the hospital, involves 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 the procedure is usually no more uncomfortable than a vaginal exam.

Sexual Intercourse
Having intercourse has been suggested as an alternative for inducing labor because the prostaglandin in ejaculate may help soften the cervix.

Castor Oil
Another alternative is castor oil. Blend 2 to 4 ounces of castor oil with just enough citrus juice to make it liquid. Have another glass of fresh juice and a wash cloth drenched with hot water on hand. Drink the castor oil mixture as quickly as possible, wipe out your mouth with the cloth and rinse the mouth to remove the oily residue. Then stay close to a bathroom because the oil usually causes the bowels to empty within three hours.

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

Some women say that pitocin-induced labor is somewhat harder than spontaneous labor. Let your doctor or midwife know if you need medication to minimize the discomfort. If your doctor recommends induction, make sure you understand why, and ask the following questions:

  • What are the reasons for induction of labor? (See the list above for typical reasons.)
  • How will the induction be done?
  • What are the benefits of induction?
  • What are the risks?
  • How will my fetus be monitored?
  • What is the anticipated success rate of induction?
  • How do you know my cervix is ready?
  • Can I first try an alternative method?