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. As you probably know, everything doesn’t always go the way we plan and many women end up getting an induction to jump-start labor. The key is knowing when induction may be medically necessary, and when it may be better to wait it out. There are many ways your labor can be induced and we go through each method, how it works, what risks are involved, and what the benefits of each method are. Included are details on stripping and sweeping membranes, misoprostol (Cytotec), dinoprostone (Cervidil & Prepidil), synthetic oxytocin (Pitocin), using a laminaria or balloon catheter, and breaking your water. You will definitely want to listen to this episode to get all the information you need to determine whether induction is right for you, when is the best time to do it, and what methods you want to use for inducing labor.
Article and Resources
Your Due Date
We measure pregnancy in 40 weeks, and your due date is the end of week 40 or about 280 days from your last menstrual period. This calculation also 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.
The Last Few Weeks
The last few weeks of pregnancy are critical to your baby’s development. You pass maternal antibodies to your baby—these will help fight infections in their first days and weeks of life. Your baby is gaining weight and strength. They are increasing iron stores and developing more coordinated sucking and swallowing abilities. The last few weeks are also when your little one’s lungs mature and prepare for that first breath of air. Your baby is also storing brown fat, which will help them maintain their body temperature in the early weeks following birth. A birth before all of these processes have a chance to run their course 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, levels of progesterone decreases. These hormone changes make your uterus more sensitive to oxytocin, which is 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, which allows you to make any final preparations. You may have trouble sleeping, which could help prepare you for being awake at all hours with a new baby. It is this symphony of everything working together in sync that starts your labor. This is how it works in a perfect world, right? 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.
As you probably know, everything doesn’t always go the way we plan, and many women end up getting an induction to jump-start labor. The key is knowing when induction may be medically necessary, and when it may be better to wait it out.
Let’s start by explaining what induction is. 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, and primarily an induction is recommended when there’s a concern for the health of 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
In determining if labor induction is necessary, your doctor or midwife will be considering many factors. Some of these factors include your health and the status of your cervix. They will also take into account your baby’s health, gestational age and size, and their position in the uterus.
Reasons for Inductions
There are many reasons why your doctor or midwife may offer or suggested an induction:
- 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 at ten days after the expected due date, and 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 induction.
- 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. In the US, it is the policy of many hospitals that, when your water breaks, you have 24 hours for labor to begin before they want to induce 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 – Oligohydramnios is a condition when there is not enough amniotic fluid surrounding the baby. During pregnancy, a sac filled with a liquid called amniotic fluid surrounds your baby. Amniotic fluid helps protect your baby and the umbilical cord from trauma and infection. Your levels of amniotic fluid will fluctuate, depending on how hydrated you are, how much your baby swallows and urinates, and your baby’s kidney function. The levels of amniotic fluid are measured using ultrasound. If your care provider determines that your amniotic fluid levels are too low, then you may be diagnosed with oligohydramnios. This happens to a small percentage, between 1-5% of pregnant women. This number does increase to about 12% in women whose pregnancies go past 41 weeks because the amniotic fluid usually starts decreasing at this time.
- Suspected Large Baby – There are many reasons why some babies are larger than others. This can be due to genetics or to underlying health issues, like gestational diabetes. There is no way to measure a baby’s size and weight accurately before birth. The best measurement is from an ultrasound, and they are not 100% accurate. Macrosomia is the medical term for a big baby. Most guidelines consider a baby to be big if they weigh over 4500 grams or 9lbs 15oz. The main concern with birthing a big baby is the risk of shoulder dystocia, which happens when the baby’s shoulders become stuck. Doctors consider shoulder dystocia an emergency, with the potential to cause injury to the baby. In cases of gestational diabetes, the evidence recommending induction before 41 weeks to avoid a big baby is weak. The World Health Organization does not support induction for gestational diabetes unless the condition is not controlled or if the placenta is not providing enough nourishment to the baby.
- Suspected Small Baby – Intrauterine Growth Restriction (IUGR) At Term, which means your baby is small for their gestational age. Just as with a big baby, this can be due to genetics. Some babies are just small, and some have restricted growth because they are not receiving enough nourishment from the placenta. Again, as with big babies, these measurements are taken with an ultrasound, and it is not 100% accurate, and it relies on accurate dating of your due date.
- Additional Reasons for an Induction – Some additional reasons for induction can be that you have a medical condition that might put you or your baby at risk, such as high blood pressure or diabetes. If there is an infection in your uterus, or if your placenta has begun to deteriorate.
The last reason for induction could be choice or convenience. Perhaps you live far from the hospital or birthing center, and you have a history of speedy deliveries. You may prefer to give birth with a specific practitioner and want to go into labor when they are present. In these cases, your care provider should confirm that your baby’s gestational age is at least 39 weeks, preferably 40. This is critical because making sure your little one is full-term helps reduce risks of health problems for them. Any decision to induce labor should be discussed with your doctor or midwife in detail to weigh any potential risks with the benefits.
Contraindication to Induction
There are some instances in which a care provider does not recommend inducing labor. One reason is a prior C-section with a classical incision or major surgery on your uterus. In this case, if your care provider does recommend an induction, they may avoid certain medications to reduce the risk of a uterine rupture. Induction is not recommended if you have placenta previa, which is a condition in which the placenta is blocking your cervix. If your baby is transverse, so they are lying crosswise in your uterus, an induction is contraindicated. Lastly, if you have an active genital herpes infection, it is unlikely your provider would recommend an induction.
Options for Inducing Labor
There are multiple methods for inducing labor. All of these procedures take place at a birth center or hospital where your care provider can monitor you and your baby. Your care provider may recommend a combination of these methods to induce labor.
Your doctor or midwife can strip or sweep the amniotic membranes to try and start labor. To do this, your care provider inserts their gloved finger beyond your cervical opening and rotates it to separate the amniotic sac from the wall of your uterus. This doesn’t actually induce labor, but it might speed the beginning of spontaneous labor, especially if your cervix has already started to dilate. This procedure can cause some intense cramping and spotting. If you leave your care provider’s office and bleeding becomes heavier than a normal menstrual period, please contact your doctor or midwife right away.
A Cochrane review that reviewed 44 studies, including 6940 women concluded that membrane sweeping may be effective in achieving a spontaneous onset of labor, but the evidence for this was low-certainty. Compared to no intervention, they found women who underwent membrane sweeping may be more likely to go into labor spontaneously or to have a formal induction. There was no difference in outcomes when compared to prostaglandins. There was not enough data to compare it to Pitocin, amniotomy, or misoprostol.
One study found to avoid one formal induction, sweeping of membranes must be performed in eight women. Another study found for every six women who undergo this procedure one formal induction is avoided. The only surefire way to go into labor is to wait. If you want an option that is nonpharmacological and that is minimally invasive, this could be an option.
Favorable vs. Unfavorable Cervix
Typically, your care provider will recommend a vaginal exam before an induction. The purpose is to examine your cervix to see if it has begun to dilate (open) and efface (thin). The measurements of your cervix are used to compute a Bishop score. This scoring system is on a scale of zero to 13. Cervical dilation, effacement, and station are scored zero to three points, and cervical position and consistency are scored zero to two points. A score of eight or higher is considered favorable for induction. If your care provider is only taking into account dilation, effacement, and station, a score of five or higher is regarded as favorable. The status of your cervix can have an impact on what methods of induction your care provider recommends, and how effective those methods will be.
Ripening Your Cervix
If you do not have a favorable cervix, your care provider may suggest ripening your cervix. There are a couple of ways to try this, with a mechanical dilator or a synthetic prostaglandin. A mechanical dilator opens your cervix physically. A synthetic prostaglandin is a medication taken orally or placed inside your vagina.
Mechanical dilators manually force your cervix to open. There are two options for a mechanical dilator, a balloon catheter, or a hygroscopic dilator. For the first, your care provider inserts a small balloon-tipped catheter beyond your cervical opening. Then saline is injected through the catheter, which expands the balloon, and causes your cervix to widen. The other option is a hygroscopic dilator, most commonly made from laminaria seaweed. For this, your care provider inserts small rods made from seaweed into your cervix. As it absorbs moisture and gets thicker, it opens your cervix. The hope is that your cervix is favorable within 12 to 24 hours after employing one of these methods. Both of these procedures can cause some cramping.
The Evidence on Mechanical Dilators
In a study in Japan, they compared these different types of dilators with over 17,000 participants. They found the group that used a hygroscopic dilator had fewer instrumental deliveries, roughly 15% compared to 17% in the other groups. The hygroscopic group had a lower rate of postpartum hemorrhage, about 33%, compared to 37-38% in the other groups. There was no big difference in the frequency of uterine infection between the groups and ranged from about 1-3%. Balloon catheters have been associated with 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. That did not happen in the hygroscopic group, and although it did occur in the other groups, the incidence was 0.1% or less. The researchers concluded that cervical ripening with a hygroscopic dilator appears to be a safer method.
A Cochrane review compared mechanical dilators to other methods for induction. Overall a balloon dilator has a better safety profile than medications. It tends to not be as effective as prostaglandins, but less effective than misoprostol.
There are two basic types of prostaglandins; misoprostol (brand name Cytotec) and dinoprostone (brand names Cervidil and Prepidil). Both medications ripen the cervix and cause uterine contractions. After prostaglandin use, your contractions, and your care provider will monitor your baby’s heart rate.
Misoprostol was initially approved as a medication to prevent ulcers. While it is commonly used for labor induction today, especially in the United States, it does not technically have approval from the FDA for this use. In the US, the use of misoprostol to induce labor is off label. Warnings about risks associated with its use for induction of labor remain on the label. When misoprostol it is used to induce it is effective at causing uterine contractions and ripening of the cervix.
Dinoprostone (Cervidil and Prepidil)
The other prostaglandin used to induce labor is dinoprostone, which goes by the trade names Cervidil and Prepidil. Similar to misoprostol, it also softens the cervix and causes uterine contractions. Dinoprostone is approved for labor induction by the FDA.
Evidence on Prostaglandins
One risk associated with the use of prostaglandins is uterine hyperstimulation, meaning it overstimulates your uterus to contract too much. Other maternal side effects include nausea, vomiting, diarrhea, and fever.
In comparing the two prostaglandin options, a systematic review and meta-analysis including ten different studies showed that misoprostol was more effective, but that dinoprostone was safer. In the misoprostol group, uterine hyperstimulation was more common, and fewer women required synthetic oxytocin. The other outcomes of both drugs, like APGAR scores and C-section rates, were similar. Most of the studies in this analysis were small-scale trials, and more research is needed.
There have been concerns raised of risks associated with Cytotec that include hyperstimulating the uterus, prolonged contractions, postpartum hemorrhage, and uterine rupture, among many others. Ina May Gaskin, who is perhaps the most respected figure in midwifery, has been outspoken against the use of misoprostol. Ina May has a summary of articles about misoprostol if you would like to read more.
Rupturing the Membranes
Another method you care provider can use is to break your water. This is also known as an amniotomy or rupturing the membranes. An amniotomy is typically done if the cervix is partially dilated and thinned, and the baby’s head is deep in the pelvis. Your doctor or midwife does this by making a small opening in the amniotic sac with a thin plastic hook, which is very similar to a knitting needle. When this happens, you may feel a warm gush of fluid when the sac opens. If your care provider ruptures your membranes, they will monitor your baby’s heart rate both before and after the procedure, as well as examine the amniotic fluid for traces of fecal waste, known as meconium.
Evidence on Rupturing Membranes
One randomized controlled trial of 585 women split into two groups, one who had an amniotomy and the other group who did not. 73% of women in both groups received more than one agent for induction. Unfortunately, this did not compare amniotomy alone for induction. They found the average time from induction to delivery was 19 hours in the amniotomy group, compared with 21.3 hours in the standard group. The rates of cesarean delivery did not differ. The rate of chorioamnionitis was 11.5% in the early amniotomy group and 8.5% in the standard group. There were two cord prolapses in the amniotomy group and none in the standard group. The groups did not differ in the rate of confirmed or suspected neonatal sepsis or admission to the NICU. This procedure does appear to shorten the length of labor, but there are risks associated with it.
A Cochrane review looked specifically at amniotomy for shortening spontaneous labor and found the evidence does not support routinely breaking waters for women in labor.
When you naturally go into labor, the hormone oxytocin is responsible for causing contractions. There is a synthetic version of this, most commonly known by the brand name Pitocin. Pitocin is most effective at inducing labor if your cervix has already begun to dilate and thin. Your doctor can administer this medication through an IV. Your care provider may also recommend Pitocin to augment or stimulate contractions if your labor is not progressing as quickly as they would like. With the use of Pitocin, your care provider will monitor your contractions, and your baby’s heart rate will be continuously, and this generally causes stronger contractions, which can be more uncomfortable. Synthetic oxytocin can make labor contractions really strong and lower your baby’s heart rate. This is why continuous fetal monitoring accompanies this intervention. The amount of synthetic oxytocin you are administered can be adjusted. If you do go this route, you can start with a low dose, then gradually increase it if necessary.
Evidence on Pitocin
There is a Cochrane review that looked at oxytocin alone for inducing labor. This review included 61 studies with more than 12,000 women. The quality of the evidence was generally poor. Of the 61 included studies only three have been published since 2000, the authors noted that the use of oxytocin alone appears to be of decreasing interest to researchers. The review concluded that oxytocin is an effective method for induction. Compared with expectant management, oxytocin results in more births within 24 hours. Active management with oxytocin will result in more cesarean sections and epidurals. Oxytocin induction appears safe, with very few reports of severe adverse effects. In comparing oxytocin with prostaglandins, oxytocin was less effective and resulted in more cesareans.
It is difficult to synthesize all of the data that compares one type of induction method to another. If you are considering an induction, you should be talking to your doctor or midwife about your options and working through which method has the best risk-benefit analysis for your specific situation.
Reviewing Risks and Benefits
Best case scenario, an induction leads to a successful vaginal birth with no side effects or complications. Whether or not an induction goes as planned, you get to meet your baby at the end of it. Your job is to make the best-informed decision for you and your baby. By reading this article, you are off to a great start! Let’s review some of the risks associated with inducing labor.
Inducing labor too early might result in premature birth. This poses risks for your baby, such as respiratory issues. This is why it is so critical to be accurate with your due date. If you schedule an induction and your due date is off by a week, your baby may not be full term. When babies are born prematurely, they are at higher risk of respiratory problems, low blood sugar, jaundice, irregular heart rate, and the inability to stabilize temperature. They are also more likely to have difficulty establishing breastfeeding.
- Low Heart Rate – Medications used to induce labor — synthetic oxytocin or a prostaglandin — might provoke too many contractions, which can diminish your baby’s oxygen supply and lower your baby’s heart rate.
- Infection – Your baby and your uterus are protected from infection by the amniotic sac. Once this breaks, germs like bacteria can get in more easily and cause an infection, so rupturing your membranes increases your risk for infection.
- Umbilical Cord Problems – Labor induction increases the risk of the umbilical cord prolapse. This is when the umbilical cord slips into the vagina before the baby, which can compress the cord and decrease your baby’s supply of oxygen.
- Uterine Rupture – Uterine rupture is a rare but serious complication in which the uterus tears open along the scar line from a prior C-section or major uterine surgery, which causes significant bleeding. In these cases, an emergency C-section can prevent life-threatening complications. This is a rare complication.
- Bleeding after delivery – Labor induction increases the risk of uterine atony, which occurs when your uterine muscles won’t properly contract after you give birth, and this can cause severe bleeding after delivery.
Inducing Labor and Cesarean Birth
The use of induction of labor has increased in the United States concurrently with the increase in the cesarean delivery rates. In 1990 9.5% of births were induced, and in 2008 this number rose to 23.1%. Because women who undergo induction of labor have higher rates of cesarean delivery than those who experience spontaneous labor, it has been widely assumed that induction of labor itself increases the risk of cesarean delivery. According to the American College of Obstetricians and Gynecologists, this is not exactly the case. If induction is not successful, your care provider may suggest a cesarean section. If mom and baby are not showing signs of distress, cesarean deliveries may be avoided by allowing longer durations of induction or oxytocin before deeming the induction a failure. So if you do have an induction and you are not going into labor, be sure to discuss all options with your doctor or midwife and find out if you can hold off on a c section.
How Long Does an Induction Take?
The length of time between induction and going into labor will depend 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.
The ARRIVE trial (A Randomized Trial of Induction vs. Expectant Management) is a randomized controlled trial that compared elective induction at 39 weeks with expectant management. Expectant management is watchful waiting instead of immediate treatment or intervention. The trial included 6,106 low-risk women split into two groups. For the group who was induced, there was not a specific induction protocol. 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 (method left to the discretion of the patient’s obstetric provider) in conjunction with or followed by oxytocin. It was suggested to providers that women should be allowed at least 12 hours after completion of any ripening, rupture of membranes, and use of oxytocin before considering the induction “failed.”
The main conclusion was that induction of labor at 39 weeks in low-risk women did not result in a significantly lower frequency of a composite adverse perinatal outcome. Still, it did result in a significantly lower incidence of cesarean delivery. Low-risk means these expecting mothers had no complications, they were pregnant with a single baby, who was in a vertex (head down) position, and this 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.
This study was a big deal. From an evidence-based standpoint, it provides a lot of data to support offering an induction at 39 weeks, and there some push in the medical community to routinely induce labor at 39 weeks in low-risk women. There was an editorial published in the American Journal of Obstetrics and Gynecology stating: 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.
The language we use is important. There are a lot of factors to consider when evaluating the risks and benefits of inducing labor. For any intervention, there should always be informed consent, and ultimately the choice to opt-in or out of a procedure should be your choice. In some sense, all procedures are elective, and some have more evidence than others to support them.
American College of Obstetricians and Gynecologists Opinion
In the past, the American College of Obstetricians and Gynecologists stated that “labor should be induced only when it is riskier for the baby to remain inside the mother’s uterus than to be born.” With the publication of the ARRIVE trial in 2018, they changed their guidelines. The recommendation from ACOG states: 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 benefit 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.
- Development of the state of the science regarding the use of obstetric interventions for healthy childbearing women should continue, focusing on both the health outcomes associated with induction of labor and the context in which the decision for induction of labor occurs between healthcare providers and childbearing women.
- Through a process of education and discussion, midwives can assist childbearing women to make informed decisions regarding induction of labor.
Talking to Your Doctor or Midwife
If you have any questions about inducing labor, please discuss them with your doctor or midwife. They are your partner in ensuring the safety of you and your baby and should be working with you to support your choices. As with any intervention, you should have all of the information, risks, and benefits to decide what is best for you and your baby.
Questions to Ask
There are some great questions you can ask your care provider to help determine whether induction is right for you. These questions are adapted from the BRAIN acronym and can be applied to any intervention.
- What are the benefits of an induction? Why do I need this procedure?
- What are the risks of the procedure?
- What are the alternatives? Do I have different options for how we induce labor?
- What does your gut or intuition tell you about inducing labor?
- 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?
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