Labor Induction and Augmentation - Topic Overview
Medicine to ripen the cervix and induce labor
- Misoprostol (Cytotec) is a pill taken by mouth or placed in the
vagina (using a smaller dose). It is a medicine currently approved for
treating ulcers. Using it for cervical ripening is a widely accepted but
unlabeled use of this medicine.
- Oxytocin (Pitocin) can be given through a vein
(intravenously) in small amounts to ripen the cervix.
But it usually is given after the cervix softens, to cause the uterus to
contract. Labor that is induced by oxytocin usually starts off harder and
progresses faster than labor that starts on its own, especially in first-time
mothers. If oxytocin does not induce labor or if the baby's heart rate
indicates distress, a cesarean delivery (C-section) may be needed.
- Dinoprostone (such as Cervidil or Prepidil Gel) can be inserted
as a suppository into your vagina (intravaginally). It can also be given as a
gel that is gently squirted into the opening of the cervix (intracervically).
When the cervix is ripe, labor may start on its own.
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
pelvic 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