Labor induction — also known as inducing labor — is prompting the uterus to contract during pregnancy before labor begins on its own for a vaginal birth.
A health care provider might recommend inducing labor for various reasons, primarily when there's concern for the mother's or baby's health. An important factor in predicting whether an induction will succeed is how soft and expanded the cervix is (cervical ripening). The gestational age of the baby as confirmed by early, regular ultrasounds also is important.
If a health care provider recommends labor induction, it's typically because the benefits outweigh the risks. If you're pregnant, understanding why and how labor induction is done can help you prepare.
Why it's done
To determine if labor induction is necessary, a health care provider will likely evaluate several factors. These include the mother's health and the status of the cervix. They also include the baby's health, gestational age, weight, size and position in the uterus. Reasons to induce labor include:
- Nearing 1 to 2 weeks beyond the due date without labor starting (postterm pregnancy).
- When labor doesn't begin after the water breaks (prelabor rupture of membranes).
- An infection in the uterus (chorioamnionitis).
- When the baby's estimated weight is less than the 10th percentile for gestational age (fetal growth restriction).
- When there's not enough amniotic fluid surrounding the baby (oligohydramnios).
- Possibly when diabetes develops during pregnancy (gestational diabetes), or diabetes exists before pregnancy.
- Developing high blood pressure in combination with signs of damage to another organ system (preeclampsia) during pregnancy. Or having high blood pressure before pregnancy, developing it before 20 weeks of pregnancy (chronic high blood pressure) or developing the condition after 20 weeks of pregnancy (gestational hypertension).
- When the placenta peels away from the inner wall of the uterus before delivery — either partially or completely (placental abruption).
- Having certain medical conditions. These include heart, lung or kidney disease and obesity.
Elective labor induction is the starting of labor for convenience when there's no medical need. It can be useful for women who live far from the hospital or birthing center or who have a history of fast deliveries.
A scheduled induction might help avoid delivery without help. In such cases, a health care provider will confirm that the baby's gestational age is at least 39 weeks or older before induction to reduce the risk of health problems for the baby.
As a result of recent studies, women with low-risk pregnancies are being offered labor induction at 39 to 40 weeks. Research shows that inducing labor at this time reduces several risks, including having a stillbirth, having a large baby and developing high blood pressure as the pregnancy goes on. It's important that women and their providers share in decisions to induce labor at 39 to 40 weeks.
Labor induction carries various risks, including:
- Failed induction. An induction might be considered failed if the methods used don't result in a vaginal delivery after 24 or more hours. In such cases, a C-section might be necessary.
- Low fetal heart rate. The medications used to induce labor — oxytocin or a prostaglandin — might cause the uterus to contract too much, which can lessen the baby's oxygen supply and lower the baby's heart rate.
- Infection. Some methods of labor induction, such as rupturing the membranes, might increase the risk of infection for both mother and baby. The longer the time between membrane rupture and labor, the higher the risk of an infection.
Uterine rupture. This is a rare but serious complication in which the uterus tears along the scar line from a prior C-section or major uterine surgery. Rarely, uterine rupture can also occur in women who have not had previous uterine surgery.
An emergency C-section is needed to prevent life-threatening complications. The uterus might need to be removed.
- Bleeding after delivery. Labor induction increases the risk that the uterine muscles won't properly contract after giving birth, which can lead to serious bleeding after delivery.
Labor induction isn't for everyone. It might not be an option if:
- You've had a C-section with a classical incision or major uterine surgery
- The placenta is blocking the cervix (placenta previa)
- Your baby is lying buttocks first (breech) or sideways (transverse lie)
- You have an active genital herpes infection
- The umbilical cord slips into the vagina before delivery (umbilical cord prolapse)
If you have had a C-section and have labor induced, your health care provider is likely to avoid certain medications to reduce the risk of uterine rupture.
How you prepare
Labor induction is typically done in a hospital or birthing center. That's because mother and baby can be monitored there, and labor and delivery services are readily available.
What you can expect
During the procedure
There are various ways of inducing labor. Depending on the circumstances, the health care provider might use one of the following ways or a combination of them. The provider might:
Ripen the cervix. Sometimes prostaglandins, versions of chemicals the body naturally produces, are placed inside the vagina or taken by mouth to thin or soften (ripen) the cervix. After prostaglandin use, the contractions and the baby's heart rate are monitored.
In other cases, a small tube (catheter) with an inflatable balloon on the end is inserted into the cervix. Filling the balloon with saline and resting it against the inside of the cervix helps ripen the cervix.
- Sweep the membranes of the amniotic sac. With this technique, also known as stripping the membranes, the health care provider sweeps a gloved finger over the covering of the amniotic sac near the fetus. This separates the sac from the cervix and the lower uterine wall, which might help start labor.
Rupture the amniotic sac. With this technique, also known as an amniotomy, the health care provider makes a small opening in the amniotic sac. The hole causes the water to break, which might help labor go forward.
An amniotomy is done only if the cervix is partially dilated and thinned, and the baby's head is deep in the pelvis. The baby's heart rate is monitored before and after the procedure.
- Inject a medication into a vein. In the hospital, a health care provider might inject a version of oxytocin (Pitocin) — a hormone that causes the uterus to contract — into a vein. Oxytocin is more effective at speeding up labor that has already begun than it is as at cervical ripening. The provider monitors contractions and the baby's heart rate.
How long it takes for labor to start depends on how ripe the cervix is when the induction starts, the induction techniques used and how the body responds to them. It can take minutes to hours.
After the procedure
In most cases, labor induction leads to a vaginal birth. A failed induction, one in which the procedure doesn't lead to a vaginal birth, might require another induction or a C-section.