Labor Induction

A quick look at inducing labor

• Inducing labor, or labor induction, occurs when an obstetrician starts a mother’s labor through medical intervention instead of waiting for labor to begin naturally.
• We typically induce labor when a known medical problem could be harmful to the mother or her baby, or if a pregnancy lasts longer than 41 and a half weeks.
• Labor can be induced with the assistance of medications, such as oxytocin and prostaglandins, or with physical interventions like an amniotomy, which causes a woman’s water to break.

What is labor induction?

During a normal labor the uterine muscles contract, tighten and relax, which helps dilate the mother’s cervix and begins to move the baby out of the uterus. This process is known as contractions. As the woman’s body prepares for labor and delivery, her cervix begins to soften, thin out and eventually open.

For most mothers, this process typically begins a few weeks before labor actually starts, although it can vary for each woman. Inducing labor is stimulating the process of contractions through medical means.

Obstetricians typically use the Bishop score, or cervix score, to help determine whether or not the mother’s cervix is likely to respond to labor induction. According to the American College of Obstetricians and Gynecologists (ACOG), the Bishop scoring system ranges from 0-13. A score of less than 6 means the cervix is not favorable, meaning the mother’s body may take longer to respond to the induction process or, rarely, to not respond at all.

How long does induced labor last?

There is a popular belief that inducing labor will allow parents to “schedule” their baby’s birth, but this is not the case. While medically inducing labor begins the labor process, labor time to the baby’s birth can vary for each woman. After labor is induced, the birth process will proceed naturally and may be quick (hours) or longer (more than a day) for the baby to make his or her arrival. During labor, the mother will stay in the hospital for monitoring and care.

When we might induce labor

There are many reasons an obstetrician may recommend inducing labor. The most important reason is for the safety of the mother and baby. Some common reasons for inducing labor include:

• Labor is delayed beyond a week and a half of the expected due date.
• The baby’s growth rate is slower than expected.
• The woman’s water has broken (the amniotic sac has already ruptured) but labor has not started. This is also referred to as premature rupture of membranes, meaning the water has broken prior to the onset of labor.
• The woman develops high blood pressure during pregnancy.
• The woman develops a form of diabetes during pregnancy.
• The amount of amniotic fluid has significantly decreased.
• Maternal age greater than 40 years.

Inducing labor for nonmedical reasons

More recently there has been an increase in mothers and couples who want to induce labor for nonmedical reasons. ACOG very clearly recommends that elective inductions of labor should never occur before 39 weeks of gestation (pregnancy). Unnecessarily inducing labor, especially early, can increase health risks for both mother and baby, plus can increase medical costs.

Options for inducing labor

Medications

A doctor may use medication to help induce labor. While all medications come with some risks, labor induction medications are typically synthetic versions of naturally produced hormones (not chemicals) that the body will recognize.

• Prostaglandins are naturally produced substances that cause the mother’s cervix to ripen, meaning thin out or soften to allow for dilation. The medically produced versions of prostaglandins (e.g. Cervidil or Cytotec brand names) accomplish the same task. Cervidil is a vaginal suppository. Cytotec can be taken by mouth or it can be administered vaginally.
• Pitocin is a synthetic version of oxytocin. Oxytocin is the natural hormone that the mother’s body produces to stimulate the start of contractions. This medication can be administered to spur labor that has stalled, or is going slower than the doctor believes is safe for the mother and baby. Pitocin is given through an IV, beginning as a small dose and increased until labor is progressing well. The infusion of Pitocin will typically achieve strong contractions every three minutes, creating an adequate labor pattern.

Physical interventions

An obstetrician may use a physical intervention to help induce labor. These interventions can be done by the doctor with or without an instrument and don’t require medications.

• Stripping the membranes to soften the cervix: The doctor will sweep a gloved finger between the membranes of the amniotic sac and the cervix to cause a separation, hopefully stimulating the mother’s body to release prostaglandins. Prostaglandins help soften the cervix to allow for better dilation.
• Amniotomy to cause the water to break: If the cervix is dilated and the baby’s head has moved down to the pelvis, an obstetrician may rupture the amniotic sac with the help of a special tool, which looks similar to a knitting hook, to puncture the sac, causing a woman’s water to break. While this intervention may cause some discomfort, it can help start labor.
• Another intervention to induce labor involves inserting a small catheter with an inflatable balloon on the end into the cervix to help the cervix stretch and dilate.

Risks of inducing labor

The ultimate goal with labor and delivery is to have a healthy mother and baby, and to do that, it may be necessary to induce labor. As with any medical intervention, there are some associated risks. Our doctors always assess possible risks and discuss these with the mother or couple.

Pitocin

During contractions, the muscle fibers of the uterus temporarily compress and squeeze the blood vessels (during the actual contraction), decreasing the blood supply to the placenta. If the uterus is overstimulated, or contracts too often, the frequency of contractions could temporarily decrease oxygen delivery to the baby, thereby affecting the baby’s heart rate. The doctor will confirm contractions are not too close together or too strong to ensure the baby’s safety.

Amniotomy

There is an increased chance of both the mother and baby developing an infection after labor induction, particularly with the amniotomy. The amniotic sac protects the baby and uterus from bacteria, so if it is ruptured and contractions do not progress, it means more time without that protection. This is one of the reasons the doctor monitors contractions to ensure they progress as expected.

Other complications

After every delivery (vaginal or C-section), the uterus needs to contract very firmly and very consistently after the delivery of the baby and placenta. There may be an increased risk of bleeding after delivery if the uterus does not have tone (described as uterine atony), which can occur if the uterine muscle is overly tired from a longer labor. Longer labors can be associated with labor induction, although can happen with both natural and induced labor. The obstetrician will continuously monitor the mother’s vital signs in order to help prevent uterine atony from occurring.

A rare, but serious complication that can occur during labor induction is a uterine rupture, or a tear in the uterus. If a mother has had a C-section in a prior pregnancy, there is a higher risk of this complication because of the scar left on the uterus from the C-section.

Inducing labor & C-sections

Labor induction may not always be effective. If labor doesn’t progress as needed, the doctor may recommend C-section in order to keep the baby and mother healthy. There is conflicting evidence on whether inducing labor results in a greater chance of first-time mothers needing cesarean sections. A study published in the New England Journal of Medicine found that healthy women with normal pregnancies can induce labor without increasing their chances of a C-section, while ACOG states the opposite.

At CU Medicine OB-GYN, we do not push a patient to labor induction. We prefer babies come naturally on their own when they’re ready. Instead, we focus on the health of the mother and baby as an indicator for how to handle the final few weeks of each pregnancy.