Medical Ways to Induce Labor
Overview and Considerations

Amniotomy |  Pitocin |  Cervical Ripening Agents

As there are numerous medical ways to induce labor as well as natural ways to induce labor, this article will address only the most common medical methods. It's important to note that true reasons for induction such as serious maternal or fetal medical conditions or true post-date complications have been found to occur only in approximately 3% of pregnancies. Despite the evidence, the current induction rates are estimated at 1 in 5, or approximately 20% of pregnancies.

In the Listening to Mothers nationwide survey (2002), 44% of women reported their caregiver tried to induce labor. 18% cited a non-medical reason as the only reason to induce labor. 16% reported a combination of medical and non-medical reasons led to the choice to induce.

A different study, titled "First Births - A Continuous Quality Improvement Project" revealed that a 22% reduction in labor inductions in first-time mothers resulted in a 21% decrease in cesarean births. No significant changes in newborn health or outcomes were noted.

The disadvantages of medical ways to induce labor are numerous. All methods are invasive and when performed before a woman's body is ready for labor, can lead to an unwanted and unnecessary "cascade of interventions".

This "cascade of interventions" references that medical ways to induce labor cannot be performed in isolation. The choice to induce requires the use of multiple interventions, each of which add their own set of risks to the birth. Each medical technique requires the mother to lie in bed. This counteracts the effects of gravity and prohibits freedom of movement, both of which can slow labor. Most also require intravenous fluids which can alter the body's hormone levels for labor, also causing it to falter or become difficult to regulate.

All of the medical ways to induce labor can lead to stronger, more painful, and more frequent contractions, which may lead the mother to use pain medications that would otherwise not be requested. These powerful contractions may also limit oxygen supply to the baby, thus increasing the risk of fetal distress.

Due to the unreliability of calculating due dates, and the variation in the amount of time any given baby requires to reach full maturity, early induction carries a risk of causing a premature birth. As increasing research has emerged in this area, there has been a nationwide push to limit early inductions and c-sections to after 39 weeks gestation to limit the incidence of avoidable preterm birth and respiratory distress secondary to early elective delivery.

Most medical ways to induce labor either aim to ripen the cervix with prostaglandins (natural or artificial) or to start uterine contractions.

AMNIOTOMY

This is commonly referred to as "breaking your water" but is also known as "artificial rupture of membranes" (AROM). It is also considered the most "natural" of all the medical ways to induce labor. An amniotomy hook, similar to a crochet hook is inserted to tear open the bag of waters and release the amniotic fluid. This method is usually chosen if the cervix is already around four centimeters dilated and is already somewhat effaced.

It is commonly used to "speed up" labor. However, when used inappropriately or before a woman is truly ready for labor, as is typically the case, it can lead to an avoidable cesarean section. This occurs for several reasons:

Once the bag of waters is ruptured, the clock starts ticking. Most obstetricians want the baby birthed as soon as 6 hours post-onset to reduce the risk of infection from the introduction of bacteria into the vagina due to repeated vaginal exams. Some OBs will wait as long as 24 hours but that is less common. In contrast, midwives, who do not routinely perform cervical checks unless specifically indicated or requested, thus limiting the chance of infection, will often allow up to 36 hours as long as no indications of an active infection are present.

Another disadvantage is that once the procedure is performed, women are most likely required to remain prone in bed. Continuous electronic fetal monitoring is also likely, which will further restrict freedom of movement. With an IV added, the mother will barely be able to roll over in bed. It also eliminates gravity and walking, both of which are proven to aid in speeding labor. In effect, the procedure can actually have the opposite effect.

This series of interventions is due in part to offset the risk of a prolapsed cord, where the umbilical cord falls into the birth canal in front of the baby, which is more likely to occur after the waters have been ruptured if the baby is still floating high in the pelvis. This is a serious situation as the cord is at risk of being compressed between the pelvic bones and the baby's head/shoulders during contractions, which will limit oxygen supply to the baby, thus causing fetal distress. It is most likely to occur in the first 20 minutes after the bag of waters has been broken and typically necessitates an immediate emergency c-section.

Amniotomy can also result in a little-considered side effect. The bag of waters not only protects the baby, but it also acts as a cushion between the baby's head and the cervix. To put things in perspective, imagine the bag of waters as a pillow and the baby's head as a bowling ball. Visualize the bowling ball (baby's head) repeatedly pushing down into the cervix. Now, visualize a pillow between the bowling ball (baby's head) and the cervix. The difference in comfort level between the two scenarios is obvious.

When breaking the waters does not lead to steady contractions or the ticking clock is expiring, then the next method of inducing labor may be attempted.

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PITOCIN INDUCTION

In a pitocin induction, the mother will be required to lie in bed with an IV and continuous fetal monitoring. Pitocin is the synthetic form of oxytocin, the natural labor-causing hormone that is produced by the mother's own body. Pitocin is given in doses through an IV (intravenous line or catheter). Every half hour or so, the nurse or obstetrician checks the uterus's response to the current dose of Pitocin, and makes an adjustment. A survey by Robbie Davis-Floyd, a cultural anthropologist at the University of Texas, found that 81 percent of women in US hospitals receive Pitocin either to induce or augment their labors.

While doctors have been able to replicate oxytocin, they are not able to replicate the method of delivery. When a woman's body releases oxytocin during a contraction, it is released in a burst-rest-burst-rest pattern, not as a continuous drip. After each contraction, the uterus has a latency, or rest, period. When the next contraction begins, anther burst of oxytocin is released. This start-stop-start-stop method prevents the uterus from becoming hyperstimulated, which can then limit oxygen to the baby and lead to fetal distress.

In contrast, when pitocin is administered in the hospital, it is given via an IV drip. Although it may be set at a low rate, it is still a consistent drip. If labor is not progressing fast enough for the doctor's liking, the drip is often increased. This leads to rapid, constant contractions that can commonly cause the uterus to become hyperstimulated and lead to the cascade of interventions previously detailed.

Sometimes, the pitocin is intentionally dosed too aggressively, typically to accommodate the hospital's or physician's schedule. This high level dose can ultimate leading to fetal distress and an avoidable iatrogenic (physician-caused) cesarean section. This is commonly termed "pit-to-distress" syndrome.

Another common type of induction is the use of various cervical ripening agents. However, these agents are actually the first step. They are seldom used alone and are typically followed by one of the previously mentioned interventions.

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CERVICAL RIPENING AGENTS

In this type of induction, either a gel (Prepidil) is placed within or around the cervix with a syringe, or a tampon-like insert (Cervidil) is placed inside the vagina with a time-release medication. The latter can be removed if hyperstimulation occurs.

Some doctors will recommend Cytotec (Misoprostol) for induction. This comes in tablet form that is either placed behind the cervix or given orally. It is cheap and more likely to start labor than either Cervidil or Prepidil. However, Cytotec is NOT approved by the FDA for labor induction. Few scientific trials have been done to establish effective dosage, effectiveness, preferred method of delivery and safety for mother and baby. An increased risk of uterine rupture, especially in VBAC moms has been documented. The drug carries a black box warning advising against its use in pregnancy, birth or while breastfeeding.

If the disadvantages and potential complications accompanying medical ways to induce labor are still unclear, ask your care provider for a copy of the hospital consent form for induction. Typically, it will read something like this: "risks may include a longer labor, increased hospital stay and recovery time, a higher chance of forceps and/or vacuum extraction, more bleeding or infection, and increased cesarean rates."

References

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Page Last Modified by Catherine Beier, MS, CBE