induction of labor

Archived User

induction of labor

I am very confused and extremely frustrated.  I have been a nurse and a Lamaze educator for many years and I have always kept up with research.  However, I just found out yesterday that our hospital is doing elective inductions routinely at 39 weeks because the research says that there are no different outcomes for mom and baby in comparison to spontaneous onset of labor.  I was referred to the Institute of Health care website where I found a Clinician's Guide on this topic, but I failed to read it and have this interpretation.  PLEASE can you tell me what ACOG guidelines are on elective inductions currently and can you comment on the study they referred to entitled Maternal and Neonatal Outcomes of Elective Induction of Labor: A Systematic Review and Cost-Effectiveness Analysis (2008) by Stanford University? 

Thank you SO much,

Brenda Brauer

Henci Goer

RE: induction of labor
(in response to Archived User)

Let’s start with guidelines. ACOG’s 2009 induction guidelines (citation below--no electronic link available) make no mention of induction’s effect on delivery route except to say that cervical ripening reduces the rate of “failed induction” (p. 386), that an unfavorable cervix is defined as having a Bishop score less than 6 and that with scores > 8 “the probability of vaginal delivery after labor induction is similar to that after spontaneous labor” (p. 387). This would seem to imply that using cervical ripening agents with an unfavorable cervix gets rid of the problem of “failed inductions,” but this is not the case. I have just finished reviewing the studies on elective and preventive induction, a.k.a. AMOR-IPAT, a pseudo-scientific system for justifying elective induction, for the upcoming new edition of Obstetric Myths Vs. Research Realities, and I can tell you that ACOG’s circumlocutions obscure that cervical ripening with an unripe cervix does not eliminate the excess risk of c/sec, that studies consistently show that women having a first baby have roughly double the risk of c/sec when induced electively compared with spontaneous labor onset, and that women with only prior vaginal births also have an increased risk--although the excess cesarean rate is much smaller--when induced with an unripe cervix, ripening agent or not. As for indications, ACOG states, “Labor also may be induced for logistic reasons, for example, risk of rapid labor, distance from hospital, or psychosocial indications” (p. 389), which pretty much covers the board for inducing electively other than ob on vacation. They do add that induction should not be attempted until the fetus has reached “39 weeks of gestation” or lung maturity is documented, but this is hardly reassuring. For one thing, I put that number in quotation marks to show that it is ambiguous. The new mandate is not to attempt elective delivery until 39 completed weeks, or the beginning of the week that ends with the due date. For another, the guidelines say that an ultrasound measurement as late as 20 wks is sufficient to firmly establish gestational age, which believe me, it isn’t with second trimester ultrasounds.

The U.K. also has induction guidelines produced by the National Institute for Health and Clinical Excellence and updated as of 2008. The contrast with ACOG’s guidelines is striking, especially when one considers that the U.K. has a much better reputation for basing maternity care guidelines on the evidence and that their guidelines are developed by an independent group of representatives of all stakeholders, not a single professional organization interested in protecting the interests of its members and without input from others or external oversight. The NIHCE introduction states: “When labour was induced [in the U.K.] using pharmacological methods (whether or not surgical induction [breaking the bag of waters] was also attempted), less than two thirds of women gave birth without further intervention, with about 15% having instrumental births and 22% having emergency [just means cesareans during labor] caesarean sections. Induction of labour has a large impact on the health of women and their babies and so needs to be clearly clinically justified” p.3. Presumably for this reason, the section on indications for induction states: “Induction of labour should not routinely be offered on maternal request alone. However, under exceptional circumstances (for example, if the woman’s partner is soon to be posted abroad with the armed forces), induction may be considered at or after 40 weeks” (emphasis mine) (p.12).

Turning to the government-sponsored systematic review to which the doctors at your hospital referred, I have both the full Agency for Healthcare Research Quality review and the summary paper published in the Annals of Internal Medicine. The short version is that if you are familiar with the AHRQ systematic review of so-called “maternal request cesarean,” this is more of the same: a heavily flawed review conducted by strongly biased reviewers--in the case of elective cesarean, led by a urogynecologist and in the case of elective induction, by a co-author of papers advocating “preventive induction,” which, as I mentioned above, is elective induction by another name.

Time and space prevent enumerating all the problems with this review, but let me hit a few highlights, starting with theory. The reviewers argue that the large body of research comparing elective induction with spontaneous labor week-by-week after term, which consistently finds that inducing increases risk of cesarean even after adjustment for factors such as birth weight, is not valid. The real question is not the comparison in any given week, but whether women reaching term are better off with planned induction at some given point given that planned expectant management will end in substantial numbers of women being induced later on and having even greater rates of c/sec as a result and that the rate of c/sec rises as gestational age increases even with spontaneous onset. The flaw in that argument is the assumption that high induction rates and higher c/sec rates as gestational age advances are inevitable rather than a matter of practice variation. Studies in which physiologic care was the norm firmly come down on the side of the latter. Among 5 studies of planned home birth and a sixth study of a rural hospital with no c/sec capability (Ackerman-Liebrich 1996; Janssen 2002; Johnson 2005; Leeman 2002; van der Hulst 2004; Woodcock 1994), induction rates overall ranged from 2% to 14% and total c/sec rates from 4% to 8% with equally good outcomes compared with similar women planning hospital birth.

The reviewers then turn to randomized controlled trials of elective induction to make their case. The reviewers call the comparison group “expectant management,” but I will call it the “control group” because elective induction was explicitly permitted in two of the trials, including Hannah (1992), by far the largest. The RCTs, in contrast to the observational studies, consistently find increased c/sec rates in the control group arms of the trial. Furthermore, more babies in the control group had meconium stained amniotic fluid. Starting with meconium staining, babies may have been more likely to have staining, but they did not have more meconium aspiration, which is the real concern. Meconium staining in the absence of other symptoms merely represents normal variability in maturing intestinal tracts. As for excess cesareans in the control group, let’s take a closer look. The Hannah 1992 “postterm” trial, actually an elective induction trial because women in the induction arm were induced after reaching 41 wks, not 42, is by far the largest of the elective induction trials, making up more than half of all participants in the analyses of pooled data from the RCTs. It epitomizes the problems found in all the RCTs. I won’t go into them here because I have critiqued this trial elsewhere on the Lamaze website, and that critique illustrates flaws that affect all of them.

These flaws, I should point out, will be invisible to people with the medical model perspective that a pregnant or laboring woman is X marks the spot where something can go wrong at any moment and that the care provider’s role is, whenever possible, to rescue the baby before disaster can occur. Clinicians with this viewpoint will find nothing peculiar with the Hannah trial, to cite a glaring example, reporting cesarean surgery rates more than 20% in both arms of the trial despite all participants being healthy women with intact membranes and no prior cesareans (if they had previous children), carrying healthy, full-term, singleton, head-down babies. The staff at your hospital undoubtedly fall in this category. I wish you luck with trying to convince them otherwise, but I'm pessimistic about your chances.

-- Henci

ACOG. Induction of labor. ACOG Practice Bulletin No 107, 2009.

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