Labor induction — also known as inducing labor — is the stimulation of uterine contractions during pregnancy before labor begins on its own to achieve a vaginal birth. A health care provider might recommend labor induction for various reasons, primarily when there's concern for a mother's health or a baby's health. One of the most important factors in predicting the likelihood of a successful labor induction is how soft and distended your cervix is (cervical ripening).
The benefits of labor induction typically 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, your health care provider will evaluate several factors, including your health, your baby's health, your baby's gestational age, weight and size, your baby's position in the uterus, and the status of your cervix. Reasons for labor induction include:
- Postterm pregnancy. You're approaching two weeks beyond your due date, and labor hasn't started naturally.
- Premature rupture of membranes. Your water has broken, but labor hasn't begun.
- Chorioamnionitis. You have an infection in your uterus.
- Fetal growth restriction. The estimated weight of your baby is less than 10 percent of what is expected for the gestational age.
- Oligohydramnios. There's not enough amniotic fluid surrounding the baby.
- Gestational diabetes. You have diabetes that develops during pregnancy.
- High blood pressure disorders of pregnancy. You have a pregnancy complication characterized by high blood pressure and signs of damage to another organ system (preeclampsia), high blood pressure that was present before pregnancy or that occurs before 20 weeks of pregnancy (chronic high blood pressure), or high blood pressure that develops after 20 weeks of pregnancy (gestational hypertension).
- Placental abruption. Your placenta peels away from the inner wall of the uterus before delivery — either partially or completely.
- Certain medical conditions. You have a medical condition such as kidney disease or obesity.
Elective labor induction is the initiation of labor for convenience in a person with a term pregnancy who doesn't medically need the intervention. Elective labor inductions might be appropriate in some instances. For example, if you live far from the hospital or birthing center or you have a history of rapid deliveries, a scheduled induction might help you avoid an unattended delivery. In such cases, your health care provider will confirm that your baby's gestational age is at least 39 weeks or older before induction to reduce the risk of health problems for your baby.
Uterine incisions used during C-sections
A C-section includes an abdominal incision and a uterine incision. After the abdominal incision, the doctor will make an incision in your uterus. Low transverse incisions are the most common (top left). Classical incisions are usually reserved for rapid delivery or for very preterm fetuses (bottom). A low vertical incision might be used if your baby is in an awkward position (top right).
Labor induction carries various risks, including:
- Failed induction. About 75 percent of first-time mothers who are induced will have a successful vaginal delivery. This means that about 25 percent of these women, who often start with an unripened cervix, might need a C-section. Your health care provider will discuss with you the possibility of a need for a C-section.
- Low heart rate. The medications used to induce labor — oxytocin or a prostaglandin — might cause abnormal or excessive contractions, which can diminish your baby's oxygen supply and lower your baby's heart rate.
- Infection. Some methods of labor induction, such as rupturing your membranes, might increase the risk of infection for both mother and baby. Prolonged membrane rupture increases the risk of an infection.
- Uterine rupture. This is a rare but serious complication in which your uterus tears open along the scar line from a prior C-section or major uterine surgery. Very rarely, uterine rupture can also occur in women who had never had previous uterine surgery. An emergency C-section is needed to prevent life-threatening complications. Your uterus might need to be removed.
- Bleeding after delivery. Labor induction increases the risk that your uterine muscles won't properly contract after you give birth (uterine atony), which can lead to serious bleeding after delivery.
Labor induction isn't appropriate for everyone. Labor induction might not be an option if:
- You've had a prior C-section with a classical incision or major uterine surgery
- The placenta is blocking your 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 your vagina before delivery (umbilical cord prolapse)
If you've had a prior C-section and have labor induced, your health care provider will avoid certain medications to reduce the risk of uterine rupture.
How you prepare
Labor induction is done in a hospital or birthing center, where you and your baby can be monitored and labor and delivery services are readily available. However, some steps might be taken prior to admission.
What you can expect
During the procedure
There are various methods for inducing labor. Depending on the circumstances, your health care provider might:
- Ripen your cervix. Sometimes synthetic prostaglandins, which are typically placed inside the vagina, are used to thin or soften (ripen) the cervix. After prostaglandin use, your contractions and your baby's heart rate will be 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.
- Rupture the amniotic sac. With this technique, also known as an amniotomy, your health care provider makes a small opening in the amniotic sac with a plastic hook. You might feel a warm gush of fluid when the sac opens, also known as your water breaking. An amniotomy is done only if the cervix is partially dilated and thinned and the baby's head is deep in the pelvis. Your baby's heart rate will be monitored before and after the procedure. Your health care provider will examine the amniotic fluid for traces of fecal waste (meconium).
- Use an intravenous medication. In the hospital, your health care provider might intravenously give you a synthetic version of oxytocin (Pitocin) — a hormone that causes the uterus to contract. Oxytocin is more effective at speeding up (augmenting) labor that has already begun than it is as a cervical ripening agent. Your contractions and your baby's heart rate will be continuously monitored.
Keep in mind that your health care provider might also use a combination of these methods to induce labor.
How long it takes for labor to start depends on how ripe your cervix is when your induction starts, the induction techniques used and how your body responds to them. If your cervix needs time to ripen, it might take days before labor begins. If you simply need a little push, you might be holding your baby in your arms in a matter of hours.
After the procedure
In most cases, labor induction leads to a successful vaginal birth. If labor induction fails, you might need to try another induction or have a C-section.
If you have a successful vaginal delivery after induction, there might be no implications for future pregnancies. If the induction leads to a C-section, your health care provider can help you decide whether to attempt a vaginal delivery with a subsequent pregnancy or to schedule a repeat C-section.
Sept. 11, 2017