Informed Choices in Childbirth
© 2002 by Henci Goer
Revised and reprinted from Childbirth Instructor Magazine
“I live an hour from the hospital; if there’s a blizzard, the road may be impassible.”
“I only get six weeks maternity leave. I don’t want to get up from my desk to go to the hospital, but I don’t want to sit home for two weeks either and only have four weeks to recover.”
“My mother can come to help me out after the baby comes, but she has to prearrange for the time.”
“If we induce labor, I can be sure of getting the doctor that I really like.”
“I’m so huge and uncomfortable and tired of being pregnant.”
Who hasn’t heard one or more of these nonmedical reasons for wanting to induce labor. Many obstetricians have no objections to elective induction, and some actually promote it: “We don’t want to let that baby get too big” is probably the most common reason given, although “impending post dates” gets my vote for most creative indication.36 The convenience of scheduling labor is even more of a boon to busy obstetricians than to their patients, so if it works and it’s harmless, why not induce?
To help your students make an informed decision, you must have the facts about elective induction. Key, of course, is whether it is generally safe and effective, but in order to accurately weigh the risks and benefits, your students will also need to know who makes a good candidate and how to minimize the likelihood of problems.
The Food and Drug Administration and the Physician’s Desk Reference, the bible of information on drugs, recommend against elective inductions.31,35 The FDA “disallows” it; the PDR says, “Since the available data are inadequate to evaluate the benefits-to-risks considerations, Pitocin [the trade name for oxytocin] is not indicated for elective induction of labor.” By contrast, the American College of Obstetricians (ACOG) includes “logistic factors” such as “risk of rapid labor, distance from hospital, psychosocial indications” on its list of indications for induction. Inductions for these reasons would be elective inductions(ACOG 1999).1 And, by ACOG’s lax standard, “tired of being pregnant” would undoubtedly qualify as a “psychosocial indication.”
Problems with inductions stem from two sources: the physiology of initiating labor and the side effects of the procedures and drugs. First, despite common belief that they can, obstetricians cannot switch labor on at will. Starting and intensifying labor involves a complex cascade of feedback mechanisms that mutually reinforce and limit each other. It is an elegant and delicate dance of hormones and other substances between the baby, who initiates and controls the process, and the mother. Dumping in oxytocin—with or without cervical ripening procedures—often won’t initiate progressive labor unless labor was on the verge of starting on its own. This is the main reason why studies consistently show that inducing labor, apart from the reason for induction, considerably increases the likelihood of cesarean section in first-time mothers.2,8-9,23,28,32,36,42,45 (Some studies have concluded otherwise. The reasons why are instructive and will be discussed in the next section.) (See Table.)
Second, all of the procedures and drugs used in inducing labor can have adverse effects.
oxytocin (Pitocin, also called “Pit”):
cesarean section: Oxytocin substantially increases the likelihood of c-section in first-time mothers. (See Table.)
procedures used with oxytocin: Administering oxytocin requires an IV and electronic fetal monitoring, which have their own potential adverse effects. Because labor is more painful, women may be more likely to want an epidural. One study comparing first-time mothers having elective inductions with first-time mothers beginning labor on their own reported that having an epidural before 4 centimeters dilation nearly quintupled the odds of cesarean, and they still doubled with epidural placement at 5 centimeters or more.36
rupturing membranes: Because amniotic fluid prevents umbilical cord compression during contractions, rupturing membranes increases the odds of episodes of abnormal fetal heart rate and cesarean section for fetal distress.12,15,28 This may be more of a problem during inductions because contraction pressures are often higher. Since the interval between rupture and birth may be long with an induction, rupturing membranes increases the risk of infection in women who subsequently have vaginal exams and women colonized with group B strep. In rare cases, it precipitates umbilical cord prolapse. Cord prolapse is most likely when membranes are ruptured early in labor when the head is still high, as would happen with inductions.
prostaglandin E2 (trade names: Prepidil, Cervidil): Prostaglandin E2, also called dinoprostone, is inserted vaginally as a gel (Prepidil) or as a removable tampon (Cervidil) to soften the cervix. It can cause uterine hyperstimulation and fetal distress. In some cases, fetal distress can lead to cesarean section.10
prostaglandin E1 (trade name: Cytosec): Prostaglandin E1, more commonly known as misoprostol is a tablet whose only FDA approved use is as an oral medication for stomach ulcers. Its manufacturer, Searle, does not formulate it for use in labor and has repudiated its use for this purpose because of safety concerns.33 The FDA says of Cytotec:11
A major adverse effect of the obstetrical use of Cytotec is hyperstimulation of the uterus which may progress to uterine tetany [sustained contraction] with marked impairment of uteroplacental blood flow, uterine rupture (requiring surgical repair, hysterectomy, and/or salpingo-oophorectomy [surgical removal of ovaries and Fallopian tubes]), or amniotic fluid embolism [very high maternal and fetal mortality rate]. Pelvic pain, retained placenta, severe genital bleeding, shock, fetal bradycardia [dangerously slow fetal heart rate], and fetal and maternal death have been reported. . . . The risk of uterine rupture increases . . . with prior uterine surgery, including Cesarean delivery. Grand multiparity [several prior births] also appears to be a risk factor for uterine rupture.
Unlike oxytocin, where the drip can be turned down or off, Cytotec cannot be rescinded if it is causing problems.
belief that technology had solved the problems with induction: The advent of IV pumps to tightly control oxytocin dose and prostaglandin gel to soften the cervix has led obstetricians to believe that technology has conquered the problems of uterine hyperstimulation and failed induction. Obstetric philosophy and training inculcates a preference for interventive management, so once they stopped thinking that inducing labor had serious consequences, induction rates were bound to soar. In fact, hyperstimulation still frequently occurs despite the pumps, and studies show that while prostaglandin gel does an excellent job of softening the cervix, it does little or nothing to reduce the cesarean rate.24,30,39 However, the preference for intervention and the belief in its value blinds many obstetricians to those truths.
the norming of cesarean section: The cesarean section rate has not been below one woman in five since 1983.40 After such an extended period, a rate in this range feels normal, right, and unavoidable, although it is far from that. If having many births end in c-section isn’t seen as a problem, then the fact that inductions lead to cesareans isn’t either.
the closure of the gap in cesarean rates between induced and spontaneous labors: The steep increase in cesarean rates has also contributed to the illusion that induction no longer matters. The gap between cesarean rates for spontaneous and induced labors has closed because the rate for spontaneous labors has risen to meet that of induced labors. To illustrate, in a 1992 study, researchers randomly assigned 3,400 women—two thirds of them first-time mothers—to planned induction at 41 weeks gestation or to await labor.18 The women assigned to induction at 41 weeks were, in effect, elective inductions since at the time, women were not considered postdates until 42 weeks. Twenty-one percent of the planned induction population had cesareans versus 25% of the expectant management group, leading the authors to conclude that planned induction was the better policy. The study has been cited since as an argument for elective induction. But these were all healthy women with full-term, singleton, head-down babies. In other words, this was a population that should have been at minimal risk for cesarean section.
A follow-up analysis reported cesarean rates according to whether labor began spontaneously or was induced.19 Among first-time mothers, 26% of women beginning labor spontaneously, whether in the planned induction or await labor group, had cesareans. This rose to 30% of women induced as planned and a whopping 42% of induced women in the await labor group, of which only 17% were done for abnormal fetal testing results.18 By comparison, a study of 12,000 low-risk women beginning labor at free-standing birth centers reported a cesarean rate of 4% with 10% of first-time mothers having cesareans.34
bias toward intervention over the natural process: The lead author of the study above thinks that every woman should have a cesarean as evidenced by her chairing a conference entitled “Choosing Delivery by Caesarean: Has Its Time Come?”17 This goes a long way toward explaining why the main paper misrepresents the true risks of induction and ignores the appallingly high cesarean rates in both spontaneous and induced labors.
The effect of obstetric bias can also be seen in one of the studies in my table. Prysak and Castronova compare outcomes in healthy mothers having elective inductions matched to women beginning labor spontaneously.32 They conclude that elective induction is “safe and efficacious” despite a cesarean rate of 16% for first-time mothers having elective inductions versus 10% for first-time mothers beginning labor on their own. The authors favor elective induction as the following passage from their introduction makes clear:
Advantages of elective induction include patient-physician convenience, efficient use of hospital personnel, and optimal time-of-day patient care; unproved advantages include lowering the risk of perinatal morbidity and mortality, birth trauma, and cesarean delivery.
How did they make their data come out “right”? They performed a logistic regression, a statistical technique that accounts for confounding factors that may obscure the true relationships among the issues of interest. (An example of an appropriate use of logistic regression would be accounting for other drug use and cigarette smoking in cocaine users to get at the true effect of cocaine on the baby.) Except that Prysak and Castronova include the need for cervical priming and the use of oxytocin in their regression, which factored out the effect of induction on outcome.
The ideal candidate for elective induction is a woman who has given birth vaginally before, whose cervix is ready for labor, and who has begun to dilate. This, of course, is also a woman who will almost certainly shortly go into labor on her own. In descending order of probability of success would be a woman with a prior vaginal birth or births whose cervix wasn’t quite ready for labor, a first-time mother whose cervix was ready to go, and a first-time mother with a long, firm, closed cervix. A woman in the last category has truly dismal chances for vaginal birth; as many as half of these labors will end in cesarean section.27 Perversely, though, if a woman’s doctor has a high cesarean rate, inducing or awaiting spontaneous labor may not matter. It will make no or only a small difference to her chance of cesarean.
(adapted from The Thinking Woman’s Guide to a Better Birth © 1999 by Henci Goer)
# # #
|STUDY||# OF PARTICIPANTS||% FIRST BABY||CESAREAN RATE Elective Induction / Spontaneous Labor|
|Overall||First Baby||Subsequent Baby|
|Almstrom 19952||321||--||18% / 12%||--||--|
|Devoe 19838||215||--||15% / 2%||--||--|
|Dublin 20009||12,534||35%||10%/ 6%||19% / 10%||4% / 4%|
|Jarvelin 199323||8606||32%||8% / 6% (1)||--||--|
|Macer 199227||506||30%||15% / 11%||34% / 22%||6% / 6%|
|Prysak 199832||922||46%||9% / 5%||16% / 10%||3% / 1%|
|Seyb 199936||1264||all||--||18% / 8%||--|
|Wigton 199442||274||36%||8% / 10% (2)||24% / 10% (2)||none|
|Yeast 199945||18,061||44%||--||16% / 8%||3% / 4%|