As the end of pregnancy nears, the cervix normally becomes soft (ripe) and begins to open (dilate) and thin (efface), preparing for labor and delivery. When labor does not naturally start on its own and vaginal delivery needs to happen soon, labor may be started artificially (induced).
Even though inducing labor is a fairly common practice, childbirth educators encourage women to learn about it and about the medicine for stimulating a stalled labor (augmentation) so that the women can help decide what is right for them.
When labor is induced for medical reasons, it is usually because it’s safer for you to have the baby now rather than risk further problems from staying pregnant.
Your labor may be induced for one of the following reasons:
Some women ask to have their labor induced when there isn't a medical reason for it (elective induction). And sometimes doctors will induce labor for nonmedical reasons, such as if you live far away from the hospital and may not make it to the hospital if you go into labor. In these situations, your doctor will wait until you are at least 39 weeks, because this is safest for your baby.
When labor does not happen as expected or as needed, inducing labor is preferred over delivering by cesarean section. If labor induction isn't successful, another attempt may be possible. In some cases, a cesarean delivery is best for the mother and baby, depending on their conditions.
There are several ways to induce labor contractions.
Medicine to ripen the cervix and induce labor
The cervix is thought to be ripe and ready for active labor when it is soft, well dilated, and effaced, and when the cervix and baby are positioned low in the pelvis. If the cervix is not ripe enough, medicines may be continued until it is.
Balloon catheter to help induce labor
A balloon catheter, such as a Foley catheter, is a narrow tube with a small balloon on the end. The doctor inserts it into the cervix and inflates the balloon. This helps the cervix open (dilate). The catheter is left in place until the cervix has opened enough for the balloon to fall out (about 3 cm).
Sweeping of the membranes to help induce labor
Sweeping, or stripping, of the amniotic membranes is a simple first step used to try to start labor. Sweeping of the membranes separates the amniotic membrane from the uterus enough so that the uterus starts making prostaglandins. This type of chemical helps trigger contractions and labor. After the cervix is open a little, this step can easily be done in your doctor's or nurse-midwife's office.
Sweeping the membranes works in 1 out of 8 women. This means that it starts labor without needing to use oxytocin or artificially rupture the membranes.2 To sweep the membranes, your doctor or nurse-midwife reaches a gloved finger through the cervix. He or she then "sweeps" the finger around the inside edge of the opening.
Sweeping the membranes is low-risk. It does not raise your risk of infection. You may start to feel uncomfortable afterward, with irregular contractions and some bleeding.2
Artificial rupture of the membranes to induce labor
To help start or speed up labor, your doctor may rupture your amniotic sac (rupture of the membranes). This should only be done after your cervix has started to open (dilate) and the baby's head is firmly descended (engaged) in your pelvis. If the membranes are ruptured too early, there is a risk of the umbilical cord slipping down around or below the baby's head (cord prolapse). If the cord gets squeezed between the baby's head and the pelvis bones, the blood supply to the baby may be reduced or stopped.
To rupture your amniotic sac (amniotomy), your doctor inserts a sterile plastic device into your vagina. This device may look like a long crochet hook or may be a smaller hook attached to the finger of a sterile glove. The hook is used to pull gently on the amniotic sac until the sac breaks. This procedure is usually not painful. A large gush of fluid usually follows the rupture of the amniotic sac. The uterus continues to produce amniotic fluid until the baby's birth. So you may continue to feel some leaking, especially right after a hard contraction.
If active labor has started on its own but contractions have slowed down or completely stopped, steps need to be taken to help labor progress (augmentation). Augmentation will be done when:
For some women, laboring in a warm tub or whirlpool (under medical care) helps with a slow labor. This can make augmentation unnecessary.3
If labor fails to progress in spite of membrane sweeping, an amniotomy, oxytocin, or a combination of these measures, delivery by cesarean section may be considered.
- American College of Obstetricians and Gynecologists (2009). Induction of labor. ACOG Practice Bulletin No. 107. Obstetrics and Gynecology, 114(5, Part 1): 386–397.
- Boulvain M, et al. (2005). Membrane sweeping for induction of labour. Cochrane Database of Systematic Reviews (1).
- Cluett ER, et al. (2004). Randomised controlled trial of labouring in water compared with standard of augmentation for management of dystocia in first stage of labour. BMJ, 328(7435): 314–320.
|Primary Medical Reviewer||Sarah Marshall, MD - Family Medicine|
|Specialist Medical Reviewer||Kirtly Jones, MD - Obstetrics and Gynecology|
|Last Revised||November 2, 2011|
Last Revised: November 2, 2011
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