About Birth

Elective Induction of Labor

Table of Contents

• Is elective induction safe and effective?
• How did obstetricians come to believe elective induction was harmless?
• Who makes a good candidate for elective induction?
• How can women considering elective induction minimize the risks?
• Bibliography

“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.

Is elective induction safe and effective?

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”): 

  • uterine hyperstimulation:  Uterine hyperstimulation is a more common and serious problem with inductions than when using oxytocin to strengthen contractions in an already established labor because it takes higher contraction pressures to get and keep a labor going from a standing start. ²⁰   Of ten studies comparing hyperstimulation rates at two different oxytocin dosages, hyperstimulation rates ranged from 2% to 60% at the lower oxytocin dose, and six of the studies reported rates of 15% or more. ¹⁴   At the higher dose, hyperstimulation rates ranged from 13% to 63%, and half reported that 25% or more of the women experienced hyperstimulation. 

  • fetal distress:  Uterine hyperstimulation can cause fetal distress.   Four studies reporting hyperstimulation rates also reported fetal distress rates. ¹⁴  One reported an 8% rate at the lower dose; the rest reported rates ranging from 15% to 54%. 

  • low Apgar score:  A separate study reported that induction increased the percentage of babies born in poor condition from 16% to 21%, doubling the odds after statistical adjustment for interdependent factors. ²¹ 

  • postpartum blood loss and neonatal jaundice. ^{4-5, 7, 13, 16, 29, 37}  Blood loss and jaundice may relate to direct effects of oxytocin; increased use of IV fluids, especially IV fluids that don’t contain salts;  or both. 

  
  

• 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: Cytotec):  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.

How did obstetricians come to believe elective induction was harmless?

• 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.

Who makes a good candidate for elective induction?

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.

How can women considering elective induction minimize the risks?

(adapted from The Thinking Woman’s Guide to a Better Birth © 1999 by Henci Goer)

• Refuse induction if you have no prior births. Induction will increase the chances of cesarean by anywhere from 50% to 250%. (See Table.)

• Refuse Cytotec (misoprostol, prostaglandin E1).  As noted above, Cytotec has a propensity for precipitating women into short, violent labors and a potential for catastrophic complications.  Cytotec was not formulated for use in inducing labor and has not been approved by the FDA for this purpose, although recently, lobbying by ACOG led the FDA to lift a ban.  Besides being riskier than Prepidil and Cervidil (prostaglandin E2), Cytotec offers no compensating advantages—at least not for women.  Cytotec produces virtually identical cesarean rates compared with inductions involving prostaglandin E2. ²²   The higher risks and equivalent effectiveness notwithstanding, hospitals like Cytotec because it costs mere pennies a dose compared with $75 to $100 dollars per dose of prostaglandin E2.   Obstetricians like it because it allows them to practice “daylight obstetrics”—insert the pill in the morning, return later in the day for the delivery or the cesarean, be home in time for dinner. ⁴¹

• Refuse rupture of membranes before labor is well-established and progressing.  Having intact membranes means you can back out if the induction doesn’t work.   Refusing early rupture also reduces the risk of fetal distress from cord compression; the risk of infection, which avoids IV antibiotics and septic workups; and the rare but catastrophic risk of umbilical cord prolapse.

• Consider refusing induction with an unready cervix and/or little or no dilation.  These conditions greatly increase the probability of cesarean section regardless of the use of cervical ripening procedures. ^{27, 43-44} 

• When cervical ripening is necessary, request Cervidil.  Unlike Prepidil, it can be removed should uterine hyperstimulation occur.

• Avoid mechanical dilators for cervical ripening.  These materials gradually dilate the cervix by absorbing water.  They are not as effective as prostaglandin E2 at either promoting successful labor induction or achieving vaginal birth, and they may increase the risk of infection. ^{25, 43}  Again, lower cost is the single advantage.

• Although this should be standard practice, make sure the IV fluid contains salts.   Salt-free fluids, especially in combination with oxytocin, one of whose effects is fluid retention, can cause serious blood-chemistry imbalances. ¹⁴

• Have continuous electronic fetal monitoring.   It reduces the risk of newborn seizures. ²⁶ 

• Insist on a low-dose(physiologic) oxytocin regimen that allows at least 30 minutes between dose increases. ¹⁴   The chance of developing adverse effects goes up with the total amount of oxytocin given and the peak dose.   High-dose regimens greatly increase both.

• Arrange to have the nurse try turning off the oxytocin once active, progressive labor is established.   When labor kicks in, it may continue on its own without the extra stimulus.   This will be less painful for you and easier on the baby.   A plain IV will be kept running, so oxytocin can easily be restarted if needed.

• Low-dose, long-interval protocols increase the odds of being able to turn the oxytocin drip down or off in active labor. ³

• Avoid or at least hold off on an epidural.   Because epidurals slow labor, they can substantially increase the risk of cesarean section, especially when given early in labor.   Epidurals also cause fevers with prolonged use. A fever in labor indicates a possible infection in mother or baby and leads to a cascade of interventions.

• Limit vaginal exams once membranes are ruptured.   There is a clear relationship between length of time since rupture, the number of vaginal exams, and infection. ³⁸

• Refuse internal contraction-pressure monitoring.   It requires rupture of membranes, increases the odds of infection, introduces risks of its own, and doesn’t improve outcomes. ⁶

1. The discrepancy might have been greater had there been more first-time mothers in the group.
2. 10% is the primary cesarean rate at the study hospital after removing cesareans for breech.

Bibliography

1. ACOG. Induction of labor. Practice Bulletin 1999, No 10.

2. Almstrom H, Granstrom L, and Ekman G. Serial antenatal monitoring compared with labor induction in post-term pregnancies. Acta Obstet Gynecol Scand 1995;74:599-603.

3. Blakemore KJ et al. A prospective comparison of hourly and quarter-hourly oxytocin dose increase intervals for the induction of labor at term. Obstet Gynecol 1990;75(5):757-61.

4. Buchan PC. Pathogenesis of neonatal hyperbilirubinaemia after induction of labor with oxytocin. Br Med J 1979;2:1255-7.

5. Chalmers I, Campbell H, and Turnbul AC. Use of oxytocin and incidence of neonatal jaundice. Br Med J 1975;2:116-8.

6. Chia YT et al. Induction of Labour: does internal tocography result in better obstetric outcome than external tocography? Aust NZ J Obstet Gynaecol 1993;33(2):159-61.

7. D’Souza SW et al. The effect of oxytocin in induced labour on neonatal jaundice. Br J Obstet Gynaecol 1979;86:133-8.

8. Devoe LD and Sholl JS. Postdates pregnancy. Assessment of fetal risk and obstetric management. J Reprod Med 1983;28(9):576-580.

9. Dublin S et al. Maternal and neonatal outcomes after induction of labor without an identified indication. Am J Obstet Gynecol 2000;183:986-94.

10. Egarter CH, Husslein PW, and Rayburn WF. Uterine hyperstimulation after low-dose prostaglandin E2 therapy: tocolytic treatment in 181 cases. Am J Obstet Gynecol 1990;163(3):794-6.

11. FDA. Cytotec 2002.

12. Garite TJ et al. The influence of elective amniotomy on fetal heart rate patterns and the course of labor in term patients: a randomized study. Am J Obstet Gynecol 1993;168(6 Pt 1):1827-1832.

13. Gilbert L, Porter W, and Brown VA. Postpartum haemorrhage—a continuing problem. Br J Obstet Gynaecol 1987;94:67-71.

14. Goer H. The Thinking Woman’s Guide to a Better Birth. New York: Perigee Books, 1999.

15. Goffinet F et al. Early amniotomy increases the frequency of fetal heart rate abnormalities. Br J Obstet Gynaecol 1997;104(5):548-53.

16. Goldberg CC et al. Effect of intrapartum use of oxytocin on estimated blood loss and hematocrit change at vaginal delivery. Am J Perinatol 1996;13(6):373-6.

17. Hannah, M. Choosing Delivery by caesarean: Has its time come? Sponsored by the University of Toronto’s Maternal, Infant, and Reproductive Health Research Unit at The Centre for Research in Women’s Health, Toronto, Canada, Nov 7, 2002.

18. Hannah ME et al. Induction of labor as compared with serial antenatal monitoring in post-term pregnancy. A randomized controlled trial. N Engl J Med 1992;326(24):1587-1592.

19. Hannah ME et al. Postterm pregnancy: putting the merits of a policy of induction of labor into perspective. Birth 1996;23(1):13-9.

20. Hauth JC et al. Uterine contraction pressures with oxytocin induction/augmentation. Obstet Gynecol 1986;68(3):305-9.

21. Herbst A, Wolner-Hanssen P, and Ingemarsson I. Risk factors for acidemia at birth. Obstet Gynecol 1997;90(1):125-30.

22. Hofmeyr GJ and Gulmezoglu AM. “Vaginal Misoprostol for Cervical Ripening and Induction of Labour (Cochrane Review).” In: The Cochrane Library, Issue 3, 2001. Oxford: Update Software.

23. Jarvelin MR, Hartikainen-Sorri AL, and Rantakallio P. Labour induction policy in hospitals of different levels of specialisation. Br J Obstet Gynaecol 1993;100(4):310-315.

24. Keirse MJNC. Prostaglandins in preinduction cervical ripening. Meta-analysis of worldwide clinical experience. J Reprod Med 1993;38(1 Suppl):89-100.

25. Krammer J et al. Pre-induction cervical ripening: a randomized comparison of two methods. Obstet Gynecol 1995;85(4):614-8.

26. MacDonald D et al. The Dublin randomized controlled trial of intrapartum fetal heart rate monitoring. Am J Obstet Gynecol 1985;152(5):524-539.

27. Macer JA et al. Elective induction versus spontaneous labor: a retrospective study of complications and outcome. Am J Obstet Gynecol 1992;166(6 Pt 1):1690-1697.

28. Mercer BM et al. Early versus late amniotomy for labor induction: a randomized trial. Am J Obstet Gynecol 1995;173(4):1321-5.

29. Orhue AAE. A randomised trial of 45 minutes and 15 minutes incremental oxytocin infusion regimes for the induction of labour in women of high parity. Br J Obstet Gynaecol 1993;100:126-9.

30. Owen J et al. A randomized, double-blind trial of prostaglandin E2 gel for cervical ripening and meta-analysis. Am J Obstet Gynecol 1991;165(4 Pt 1):991-996.

31. Parke-Davis. Physician’s Desk Reference. 52d ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

32. Prysak M and Castronova FC. Elective induction versus spontaneous labor: a case-control analysis of safety and efficacy. Obstet Gynecol 1998;92(1):47-52.

33. Reuters Health. “Off-label Cytotec Use for Labor, Abortion Prompts Searle Letter to Physicians.” Aug 29, 2000.

34. Rooks JP et al. Outcomes of care in birth centers: the National Birth Center Study. N Engl J Med 1989;321(26):1804-1811.

35. Rooks JP. Midwifery and Childbirth in America. Philadelphia: Temple University Press, 1997.

36. Seyb ST et al. Risk of cesarean delivery with elective induction of labor at term in nulliparous women. Obstet Gynecol 1999;94(4):600-7.

37. Singhi S et al. Iatrogenic neonatal and maternal hyponatraemia following oxytocin and aqueous glucose infusion during labor. Br J Obstet Gynaecol 1985;92:356-63.

38. Soper DE, Mayhall CG, and Dalton HP. Risk factors for intraamniotic infection: a prospective epidemiologic study. Am J Obstet Gynecol 1989;161(3):562-6.

39. Trofatter KF. Endocervical prostaglandin E2 gel for preinduction cervical ripening. Clinical trial results. J Reprod Med 1993;38(1 Suppl):78-82.

40. United States 1996. Month Vital Stat Rep 1997;46(1 Suppl 2).

41. vigilante obstetrics. Presented at Celebrating the Gift of Birth, sponsored by the International Cesarean Awareness Network, Cleveland, OH, Apr 20-22, 2001.

42. Wigton TR and Wolk BM. Elective and routine induction of labor. A retrospective analysis of 274 cases. J Reprod Med 1994;39(1):21-26.

43. Williams MC, Krammer J, and O’Brien WF. The value of the cervical score in predicting successful outcome of labor induction. Obstet Gynecol 1997;90(5):784-9.

44. Xenakis EM et al. Induction of labor in the nineties: conquering the unfavorable cervix. Obstet Gynecol 1997;90(2):235-9.

45. Yeast JD, Jones A, and Poskin M. Induction of labor and the relationship to cesarean delivery: a review of 7001 consecutive inductions. Am J Obstet Gynecol 1999;180(3 Pt 1):628-33.