Overview

In a perfect world, your body is ready, your baby is fully mature, and you spontaneously go into labor on your due date. In reality, nearly one in four expecting mothers undergo a procedure to induce labor. The key is knowing when inducing labor may be medically necessary and when it may be better to wait it out. Explore the many reasons a care provider may suggest an induction, from medical considerations to practical concerns. Learn your options, the various methods used to initiate labor, how each approach works, the potential risks and benefits, and why timing matters. This episode examines the evidence on all of your options, including stripping and sweeping membranes, misoprostol (Cytotec), dinoprostone (Cervidil & Prepidil), synthetic oxytocin (Pitocin), using a laminaria or balloon catheter, and breaking your water.

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Article and Resources

Your Due Date

We measured pregnancy duration in 40 weeks, and your due date is the end of week 40 or about 280 days from your last menstrual period. This calculation assumes a 28-day cycle, with ovulation about day 14. Your due date is an estimate of when your baby will arrive, and it is not an exact science. Check out this episode for more information on your due date.

The Last Few Weeks

The final weeks of pregnancy are critical to your baby’s development. During this time, you pass maternal antibodies to your baby to help fight infections in the first days and weeks of life. Your baby gains weight and strength. They increase iron stores and develop more coordinated sucking and swallowing abilities. The last few weeks are also when your baby’s lungs mature and prepare for the first breath of air. Your baby also stores brown fat, which will help it maintain its body temperature in the early weeks following birth. A birth before these processes has a chance to run its course and can make a difference in your baby’s health.

Your Body Leading Up to Labor

As your baby and your body get ready to go into labor, your placenta triggers an increase in prostaglandin that softens the cervix to prepare it for effacing and dilating. Your levels of estrogen rise, and levels of progesterone decrease. These hormone changes make your uterus more sensitive to oxytocin, the hormone responsible for contractions. Nearing labor, your baby will move further down into the pelvis. While all of this is going on internally, you may notice that you have extra energy, allowing you to make final preparations. You may have trouble sleeping, which could help prepare you for being awake at all hours with a new baby.

This symphony of everything working together in sync starts your labor. In a perfect world, everything works like it is supposed to. Your body is ready, your baby is fully mature and ready to make their entrance into the world, and you naturally go into labor.

Inducing Labor

As you probably know, everything doesn’t always go the way we plan. Many women end up getting an induction to jump-start labor. The key is knowing when inducing labor may be medically necessary and when it may be better to wait. Inducing labor is any procedure that stimulates uterine contractions during pregnancy before labor begins on its own. A care provider may recommend inducing labor for various reasons. Primarily, a doctor or midwife will recommend an induction when there’s a concern for the health of the mom or baby. Weighing the risks of an induction, which can include a premature baby or infection, against the benefits will help you decide if this is the best course of action for you and your baby.

Considerations for an Induction

Your doctor or midwife will consider many factors to determine if labor induction is necessary. Some of these factors include your health and the status of your cervix. They will also consider your baby’s health, gestational age and size, and position in the uterus.

How Long Does an Induction Take?

The length of time between inducing labor and going into labor depends on how you respond to the procedure. If your cervix needs to ripen, it could take a couple of days before labor starts. If your cervix has begun to soften, efface, and dilate, it could be as quick as a few hours.

Reasons for Inductions

There are many reasons why your doctor or midwife may offer or suggest inducing labor.

Going Past Your Due Date

You are approaching two weeks past your due date, and labor has not started naturally. Many hospitals have a policy of induction ten days after the expected due date. Many birth centers require you to go into labor within 42 weeks. If you reach the limit set by your care provider, they may recommend inducing labor.

It Has Been 24 Hours Since Your Water Broke

Your water has broken, but you’re not having contractions. When your amniotic sac ruptures before labor begins, it is called premature rupture of membranes. PROM complicates 2-3% of pregnancies in the United States. It is the policy of many hospitals that when your water breaks, you have 24 hours for labor to begin before inducing labor. The reason for this is that you are at an increased risk for infection once your amniotic sac has ruptured.

Not Enough Amniotic Fluid

During pregnancy, a sac filled with amniotic fluid surrounds your baby. This protects both the baby and the umbilical cord from trauma and infection. The amount of amniotic fluid fluctuates based on your hydration, how much your baby swallows and urinates, and your baby’s kidney function. Healthcare providers use ultrasounds to measure these fluid levels. If the level is too low, the condition is called oligohydramnios, which occurs in 1-5% of pregnancies. This percentage rises to about 12% in women who go past 41 weeks, as amniotic fluid typically begins to decrease at that time.

Suspected Large Baby

Some babies are larger than average due to factors like genetics or underlying health issues such as gestational diabetes. While an ultrasound is currently the best tool to estimate a baby’s weight and size before birth, it isn’t 100% accurate. The medical term for a larger-than-average baby is macrosomia, generally defined as weighing more than 4,500 grams (9 lbs 15 oz). A study examining over 26,000 pregnancies with an ultrasound between 35 and 38 weeks had 2,241 babies deemed large for gestational age. When they compared birth weight to ultrasound measurements, 8.6% of the time, the ultrasound falsely identified a baby as large when they weren’t. Ultrasounds were more accurate at predicting large for gestational age babies in a subgroup of pregnancies scanned for a suspected large baby.

One major concern when delivering a big baby is shoulder dystocia, which occurs when the baby’s shoulders become stuck during birth. Risks to the baby include injury to the brachial plexus (nerves in the shoulder), fractures, or oxygen deprivation if the umbilical cord is compressed for too long. Risks to the mother include significant tearing, heavy bleeding, or injury to the uterus.

Suspected Small Baby

Some babies are smaller than average at birth. Like larger babies, genetics can sometimes explain this; some babies are simply on the smaller side. In other cases, this can result from intrauterine growth restriction if a baby is not receiving enough nourishment from the placenta. Similar to estimating a baby’s larger size, determining if it is small for its gestational age relies on ultrasound measurements. A study examining third-trimester ultrasounds to identify small-for-gestational-age babies found that many cases were missed. Although ultrasounds are not always accurate, they are the best tool for estimating your baby’s size. Learn more about ultrasound accuracy for predicting your baby’s size in this episode.

Additional Reasons for an Induction

Your doctor may also recommend inducing labor if you have certain medical conditions, such as high blood pressure, that increase risks for you or your baby. Other factors include an infection in your uterus or a deteriorating placenta. In these cases, inducing labor can help protect both you and your baby’s health.

Elective Induction

In some cases, you may consider an induction for personal reasons, such as living far from the hospital or birthing center or having a history of rapid deliveries. You might also prefer to deliver under the care of a specific practitioner and want to schedule labor when they are available. If you opt for induction due to convenience, it is essential to confirm that your baby’s gestational age is at least 39 weeks, ideally 40, to reduce the risk of potential health issues. Any decision to induce labor should be in close consultation with your doctor or midwife to carefully weigh the benefits against the risks.

Contraindication to Induction

There are certain situations where a care provider may advise against inducing labor. One is if you’ve had a prior C-section with a classical incision or another major uterine surgery, in which case some induction methods may increase the risk of uterine rupture. Another is placenta previa, where the placenta is blocking the cervix. Induction is generally contraindicated if your baby is in a transverse (lying crosswise). Lastly, if you have an active herpes simplex infection, a care provider is unlikely to recommend inducing labor.

Options for Inducing Labor

There are several methods to induce labor. All are typically performed in a hospital or birth center where you and your baby can be closely monitored. Your care provider may recommend using a combination of these methods to help initiate and progress labor. Let’s examine your options for inducing labor.

Membrane Sweep

Your doctor or midwife may offer to strip or sweep the amniotic membranes to encourage labor. During this procedure, your care provider inserts a gloved finger through your cervical opening and gently separates the amniotic sac from the uterine wall. Although this doesn’t directly induce labor, it may speed up the onset of spontaneous labor, especially if your cervix has already begun to dilate. This procedure can cause cramping and spotting. If you experience bleeding heavier than a normal menstrual period once you leave your care provider’s office, contact them immediately.

A Cochrane review of 44 studies involving 6,940 women concluded that membrane sweeping may effectively promote a spontaneous onset of labor, though the evidence was classified as low certainty. Compared to no intervention, women who had a membrane sweep were more likely to go into labor spontaneously or to require a formal induction. The review found no outcome difference when membrane sweeping was compared to prostaglandins. There wasn’t enough data to compare it to Pitocin, amniotomy, or misoprostol.

One study found that performing this procedure on eight women could prevent one formal induction. Another study concluded that one formal induction is avoided for every six women who undergo a membrane sweep. A membrane sweep may be worth discussing with your care provider if you want a nonpharmacological and minimally invasive approach.

Favorable vs. Unfavorable Cervix

Before recommending an induction, your care provider will usually perform a vaginal exam to check whether your cervix has started to dilate (open) and efface (thin). Your provider uses these measurements to calculate your Bishop score, which ranges from 0 to 13. Cervical dilation, effacement, and station earn between 0 and 3 points. The cervical position and consistency earn 0 to 2 points. A score of 8 or higher generally indicates a favorable cervix for inducing labor. If your provider considers only dilation, effacement, and station, a score of 5 or higher is also favorable. The condition of your cervix can influence the induction methods your care provider recommends and how effective those methods will be.

Ripening Your Cervix

If your doctor or midwife does not consider your cervix favorable, they may recommend a procedure to ripen it. Your provider can use a mechanical dilator to physically open the cervix or synthetic prostaglandins to ripen it. You take prostaglandins orally or vaginally to soften and encourage cervical dilation.

Mechanical Dilator

Mechanical dilators work by physically widening your cervix. There are two primary types: a balloon catheter or a hygroscopic dilator. A balloon catheter is a small, balloon-tipped tube inserted through your cervical opening and then filled with saline. As the balloon expands, it forces the cervix to open. A hygroscopic dilator is most often made from laminaria seaweed. Your provider inserts these small rods into your cervix to absorb moisture, thicken, and gradually open the cervix. The goal of either method is to have a favorable cervix within 12 to 24 hours. Both a balloon catheter and hygroscopic dilater can cause cramping.

The Evidence on Mechanical Dilators

A study with more than 17,000 participants compared different mechanical dilators. The hygroscopic dilator group had fewer instrumental deliveries (around 15%, compared to 17% in other groups) and a lower rate of postpartum hemorrhage (about 33% versus 37–38% in other groups). Rates of uterine infection were similar across the groups (1–3%). Balloon catheters showed a small risk of umbilical cord prolapse (0.1% or less), which did not occur in the hygroscopic group. Balloon catheters carry a risk of umbilical cord prolapse since the balloon can create a space between the cervical opening and the baby’s head, and the umbilical cord can slip down. The researchers concluded that hygroscopic dilators seem to be a safer option for cervical ripening.

A Cochrane review comparing mechanical dilators to other induction methods found that balloon catheters have a better safety profile than medications. Balloon catheters are probably as effective as the synthetic prostaglandin dinoprostone but less effective than oral misoprostol.

Prostaglandins

The two commonly used prostaglandins for labor induction are misoprostol (Cytotec) and dinoprostone (Cervidil and Prepidil). Both medications help soften the cervix and stimulate uterine contractions. After using prostaglandins, your care provider will monitor your contractions and your baby’s heart rate.

Misoprostol (Cytotec)

Misoprostol is a medication the FDA initially approved to prevent ulcers. Although it is not officially approved for labor induction, it is widely used off-label for this purpose. The FDA has not officially approved misoprostol for labor induction, and the drug’s label still includes warnings about associated risks. Despite these cautions, misoprostol is effective at causing uterine contractions and ripening the cervix.

Off-label medication use is relatively common. Once the FDA approves a drug, healthcare providers can prescribe it in ways not specifically listed on the drug’s label if they believe it will benefit the patient and if there is supporting evidence or sound medical rationale for doing so. Misoprostol is a great example of a medication doctors commonly prescribe off-label.

Dinoprostone (Cervidil and Prepidil)

Dinoprostone (Cervidil and Prepidil) is another prostaglandin that softens the cervix and causes contractions. Unlike misoprostol, the FDA approves dinoprostone specifically for labor induction.

Evidence on Prostaglandins

One notable risk of using prostaglandins is uterine hyperstimulation, which occurs when the uterus contracts too frequently or intensely. Other possible side effects include nausea, vomiting, diarrhea, and fever.

A systematic review and meta-analysis that examined 10 different studies found misoprostol to be more effective than dinoprostone but with a higher rate of uterine hyperstimulation. Additionally, fewer women in the misoprostol group required synthetic oxytocin. Both drugs showed similar outcomes for APGAR scores and C-section rates. However, many of the studies in this review were small-scale, indicating a need for more research.

There have been concerns that misoprostol can increase the risk of hyperstimulation, prolonged contractions, postpartum hemorrhage, uterine rupture, and other potential complications. Ina May Gaskin, a prominent figure in midwifery, has been vocal in opposing its use. See this article by Ina May if you want to learn more.

Rupturing the Membranes

Another method your care provider may use to induce labor is breaking your water. This is also known as an amniotomy or rupturing the membranes. Typically, an amniotomy is performed when your cervix is partially dilated and effaced, and your baby’s head is deep in the pelvis. Your doctor or midwife ruptures your membranes using a thin plastic hook, similar to a knitting needle, to create a small opening in the amniotic sac. When the sac opens, you may feel a warm gush of fluid. Your doctor or midwife will monitor your baby’s heart rate before and after the procedure, and will check the amniotic fluid for traces of meconium (your baby’s fecal waste).

Evidence on Rupturing Membranes

A randomized controlled trial involving 585 women examined early amniotomy to standard management, which was amniotomy at greater than 4 cm dilation. 73% of the women received more than one induction agent, so the study did not assess amniotomy alone as an induction method. The average time from induction to delivery was 19 hours in the early amniotomy group, compared to 21.3 hours in the standard group. Two cord prolapses occurred in the amniotomy group and none in the standard group. Chorioamnionitis (an infection in the amniotic sac) was more common in the early amniotomy group (11.5%) vs. the standard group (8.5%). There were no differences in the cesarean rate, neonatal sepsis, or NICU admissions. Overall, the procedure appeared to shorten the length of labor. It also carried additional risks, such as a slightly higher rate of infection and cord prolapse.

A Cochrane review specifically examining amniotomy for shortening spontaneous labor concluded that there is not enough evidence to support routine amniotomy for women already in labor. While breaking the water may reduce labor time, you should carefully consider the potential risks before proceeding.

Pitocin

When you naturally enter labor, the hormone oxytocin causes your uterus to contract. Your care provider may use a synthetic version of oxytocin, commonly known by the brand name Pitocin, to induce or augment labor. Pitocin is most effective when your cervix has already begun to dilate and thin. It is administered through an IV, and your care provider can adjust the dosage.

Your provider may recommend pitocin if your labor is progressing more slowly than expected. Because it typically causes stronger and more frequent contractions, it can lead to increased discomfort compared to natural labor. These intense contractions can also lower your baby’s heart rate, so continuous fetal monitoring accompanies this intervention. To minimize discomfort and risks, you can start with a low dose of Pitocin, and increase it gradually if necessary.

Evidence on Pitocin

A Cochrane review of 61 studies involving over 12,000 women examined oxytocin for inducing labor. While the quality of evidence was generally low, and only three studies were published after 2000, the findings showed that oxytocin is an effective method for induction. The authors noted that using oxytocin alone appears to be of decreasing interest to researchers. Compared to expectant management, oxytocin results in more births within 24 hours and appears safe, with very few severe adverse effects reported. Compared to prostaglandins, oxytocin was less effective and resulted in a higher rate of cesareans and epidurals.

While pitocin is effective, determining the best induction method depends on individual circumstances. If you are considering induction, it is important to discuss your options thoroughly with your doctor or midwife to evaluate the risks and benefits for your specific situation.

Reviewing Risks and Benefits

In the best-case scenario, an induction results in a successful vaginal birth without any complications or side effects. Regardless of how it unfolds, the ultimate reward is meeting your baby. Your priority is to make the most informed decision for you and your baby. By educating yourself, you’re already on the right track. Let’s take a closer look at some of the potential risks associated with inducing labor.

Premature Birth

Inducing labor too early can lead to premature birth, which is why having an accurate due date is critical. Premature babies are at higher risk for complications like respiratory problems, low blood sugar, jaundice, irregular heart rate, difficulty maintaining body temperature, and challenges with establishing breastfeeding.

Low Heart Rate

Medications used for induction, such as synthetic oxytocin or prostaglandins, can cause excessive contractions. These frequent or intense contractions may reduce your baby’s oxygen supply, leading to a lower heart rate.

Infection

The amniotic sac protects your baby and uterus from infection. Once the sac ruptures bacteria can enter more easily. This increases the risk of infection for you and your baby.

Umbilical Cord Problems

Labor induction increases the risk of umbilical cord prolapse, where the cord slips into the vagina ahead of the baby. This can compress the cord and reduce your baby’s oxygen supply, requiring immediate intervention.

Uterine Rupture

Uterine rupture is a rare but serious complication. This occurs when the uterus tears along a prior C-section scar or other uterine surgery site, leading to significant bleeding. This emergency often requires an immediate C-section to prevent life-threatening complications. Fortunately, this is very uncommon.

Bleeding after delivery

Labor induction increases the risk of uterine atony, a condition where the uterine muscles fail to contract properly after birth, which can result in severe postpartum bleeding.

Cesarean

If you or your baby are not doing well after attempting induction or the induction is not successful, your care provider may recommend a cesarean. Much of the research on inducing labor shows higher rates of cesarean delivery when labor is induced. However, according to the American College of Obstetricians and Gynecologists (ACOG), new research suggests that induction for healthy women at 39 weeks in their first full-term pregnancies may reduce the risk of cesarean birth.

ARRIVE Trial

The ARRIVE trial (A Randomized Trial of Induction vs. Expectant Management) was a significant randomized controlled study comparing elective induction at 39 weeks to expectant management in 6,106 low-risk women. Expectant management involves watchful waiting without immediate intervention. There was no specific induction protocol for the group that was induced. The recommendation was that if a patient had a favorable cervix, they would undergo an induction with oxytocin. Participants with an unfavorable cervix were expected to first undergo cervical ripening. The method was left to the discretion of the patient’s obstetric provider. Cervical ripening was in conjunction with or followed by oxytocin. Providers were advised to allow at least 12 hours after cervical ripening, rupture of membranes, and use of oxytocin before declaring the induction a failure.

The main conclusion was that induction of labor at 39 weeks in low-risk women did not significantly reduce adverse perinatal outcomes. However, it did result in a significantly lower rate of cesarean delivery. Participants were considered low-risk if they had no complications, were pregnant with a single baby in the vertex (head-down) position, and it was their first pregnancy. To give some context to what was considered a significantly lower frequency of cesarean delivery, 18.6% of the induction group had cesarean births, compared to 22.2% of the expectant management group. Their data suggested that one cesarean delivery may be avoided for every 28 deliveries among low-risk nulliparous women who plan to undergo elective induction of labor at 39 weeks.

The ARRIVE trial generated significant attention, providing evidence to support offering inductions at 39 weeks for low-risk pregnancies. Some in the medical community have advocated for routinely offering inductions at this point. An editorial in the American Journal of Obstetrics and Gynecology argued against using the term “elective” for 39-week inductions:

When the term “elective” is applied to a medical intervention, it implies that it is not really necessary. That is certainly not the case when it comes to 39-week nulliparous induction. The ARRIVE trial provides grade A (good and consistent) evidence that labor induction provided benefit with no harm to women and their infants. These inductions are not “elective.” We believe that the word “elective” should be removed completely in our discussions and professional documents about 39-week nulliparous inductions. We propose a more accurate term might be “risk-reducing,” which captures both the intent and proven benefit of 39-week inductions.

Any intervention should come with informed consent. Ultimately, deciding to opt in or out of a procedure should be your choice. In many ways, all procedures could be considered elective; some have more evidence than others to support them.

American College of Obstetricians and Gynecologists Opinion

In the past, ACOG advised that “labor should be induced only when it is more risky for the baby to remain inside the mother’s uterus than to be born.” However, following the publication of the ARRIVE trial in 2018, they updated the guidelines. ACOG now recommends: Based on the findings demonstrated in this trial, it is reasonable for obstetricians and healthcare facilities to offer elective induction of labor to low-risk nulliparous women at 39 weeks gestation. However, consideration for enactment of this elective induction of labor intervention should not only take into account the trial findings, but that this recommendation may be conditional upon the values and preferences of the pregnant woman, the resources available (including personnel), and the setting in which the intervention will be implemented. A collaborative discussion with shared-decision making should take place with the pregnant woman.

American College of Nurse Midwives Opinion

In contrast to ACOG, the American College of Nurse Midwives released a statement after the AFFIRM trial that they recommended no change in their opinion in response to this study. The ACNM official position statement includes the following points:

• Spontaneous labor offers substantial benefits to the mother and her newborn. Disruption of this process without an evidence-based medical indication represents a risk for potential harm.
• Induction of labor should be offered to women only for medical indications that are supported by scientific evidence, which indicates the benefit outweighs the risk of induction of labor, including the potential risks of prematurity or postmaturity.
• Informed consent prior to labor induction should include discussion of the normal processes of labor and the benefits and potential harms of induction, including the optimal method to use during the induction process.
• Through a process of education and discussion, midwives can assist childbearing women to make informed decisions regarding induction of labor.

Questions to Ask

Asking the right questions can help determine whether induction is the right choice for you and your baby. The BRAIN acronym is a helpful tool for evaluating any medical intervention.

• B-Benefits: What are the benefits of an induction? Why do I need this procedure?
• R-Risks: What are the risks of the procedure?
• A-Alternatives: What are the alternatives? Do I have different options for how we induce labor?
• I-Intuition: What does your gut or intuition tell you about inducing labor?
• N-Nothing: What happens if you do nothing and opt out of an induction? Can you delay an induction for a day, several days, or a week? What are the risks of postponing an induction?

Talking to Your Doctor or Midwife

The decision to induce labor is very nuanced and involves considering many factors. If you have questions about inducing labor, be sure to discuss them with your doctor or midwife. They are your partner in ensuring your and your baby’s safety and should work with you to support your choices. As with any medical intervention, it’s important to clearly understand the information, including the risks and benefits, to make the best decision for you and your baby.

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