What is Induction?
Initiating labor in a pregnant woman without contractions seems to be a simple way to explain induction of labor. For many women, induction is becoming increasingly more common. In fact, induction has been on the increase during the past decade. From 1989 until 1995, there has been a 77 percent increase in the number of inductions.
This is one of the most important questions to understand regarding induction. As physicians, we have become very comfortable with intervention in pregnancy. Initiating labor can be very simple. It is becoming so commonplace that it can lull us into misusing the process of induction. Therefore, I think it is very important to have a medical reason to induce a patient.
Reasons to induce include:
- Overdue (at least one to two weeks)
- Toxemia (elevated blood pressure)
- Premature rupture of the amniotic sac
- Infection in the uterus (chorioamnionitis)
- Problems with the baby's growth
- Low amniotic fluid (oligiohydramnios)
- Excessively large baby (macrosomia)
- Prior poor obstetrical history (prior stillborn)
- Underlying medical condition in the mother (high blood pressure, kidney disease, heart disease, etc.)
There is also a list of patients with certain conditions who should not be induced. These would include:
- Placenta previa (afterbirth in front of the baby's head)
- Prior classical c-section (incision is up and down on the uterus)
- Breech baby or other abnormal fetal positions (i.e., sideways)
- Fetal distress
- Active herpes infection
I know many obstetricians who utilize induction liberally, typically for social convenience or to accommodate their office schedule. A woman who is uncomfortable near her due date may wish to be induced. We can all sympathize with her plight, but perhaps it would be better to reassure her that what she is feeling is normal rather than induce her.
How to Induce
By detailing the process and the nuts and bolts of induction, you might gain an appreciation of my prior warning.
After determining the need for induction, your physician must do a pelvic exam to evaluate your cervical exam. Going back to your prepared childbirth classes for a moment, the cervix acts as the doorway to the uterus. It holds the baby inside for nine months. At some point in time, it begins the process of effacement (thinning out) and dilatation. The other important issue is how low the baby's head is in the birth canal. This is known as the station. The pelvic exam allows your practitioner to determine how ready you are to labor. If he or she feels that your cervix is “ripe,” you can be induced (see below). For those with an unfavorable exam, other methods need to be utilized to help in preparation for labor. This specific group of women is going to need extra help. They should also realize that they are at higher risk of needing a cesarean section.
Cervical ripening agents are available to help thin out and dilate the cervix in advance of induction. These techniques help improve your chances of a vaginal delivery. They also tend to make the induction easier. There are numerous ways to ripen the cervix. Presently, most physicians utilize a vaginal insert (Cervidil) or gel containing prostaglandin. Although prostaglandins have many functions, in obstetrics, they have a unique ability to soften and dilate the cervix without painful contractions. On occasion, they can also trigger labor or lead to over-stimulation of the uterus (known as hyperstimulation). This can cause fetal stress and potentially result in a cesarean section. These agents take at least six hours to work and are typically placed the night before labor is to begin. In many centers, including mine, we keep the patient in the hospital overnight and continually monitor them. Most of the time, the patient is able to sleep, but it isn't the best night of rest you could have. Other agents, including inflating a balloon in the uterus (a foley) and cervical dilators (laminaria) can trigger cervical ripening without the risk of hyperstimulation of the uterus. These agents tend to be less effective as cervical ripening agents, and they are more uncomfortable.
Administering Induction Medications
Once we are ready to induce, we need to initiate contractions. Most physicians will utilize oxytocin, also known as Pitocin. The medication is administered intravenously. The medication is carefully increased until regular, painful contractions are coming every three minutes. The medication doesn't always work quickly. I've had patients smiling at me for hours before the Pitocin kicks in. Some doctors may perform an amniotomy (breaking the water) as a way to initiate labor or increase the effectiveness of labor. I have found that breaking the bag makes a big difference quickly. Patients have commented on the dramatic change in the intensity of their contractions within a short time of this procedure. As with any obstetrical procedure, amniotomy should only be performed when the baby is moving down into the birth canal. If the bag is broken too soon, there is a risk that the umbilical cord can come down in front of the baby. This is known as cord prolapse. This is an obstetrical emergency with cesarean section as the only safe choice for delivery.
Once an induction is started, there is no way to predict how long labor will take. I've had inductions take as short as an hour and some lasting more than 20 hours.
Natural labor vs. induced labor
My patients tell me that an induced labor is slightly more uncomfortable than a natural labor. I believe this happens because the patient is focused on each contraction once the Pitocin is started. They don't have the luxury of ignoring some of the early contractions at home. Instead, they are watching the monitor, counting each labor pain. Once labor gets going, I think that the labors are identical.
Risks of Induction
As you might have noticed throughout this discussion, there are some potential downsides to induction. Failed inductions do occur and lead to an increased number of cesarean sections. The cervical ripening agents can trigger fetal stress and c-sections as well. On rare occasions, the uterus can rupture (especially if you've had a prior c-section or a very protracted induction).
Another issue regarding induction is the ability to monitor the contractions on a continual basis. Most obstetricians will require constant fetal monitoring while Pitocin is in use. In most settings, this will require you to remain in bed. (Some hospitals have monitoring systems that allow patients to walk during labor.)
Induction of labor is a medical procedure. It should be done for those with a medical reason. In these cases, the benefits of the induction must outweigh the risks involved. If we have a complication associated with induction, we should be able to justify our decision based on the medical necessity of the procedure. For those who undergo a social induction, anything negative that transpires during the induction is hard to justify.
Induction is a safe and effective procedure with a very important role in obstetrics. It should be used based upon sound medical judgment.