A Closer Look at the New Induction Study

The July 2010 edition of Obstetrics and Gynecology has still another study (PubMed ID # 20567165) confirming that induction doubles the risk for cesarean surgery. I have been teaching long enough to remember when elective induction was an issue only in December – both for the convenience of the doctor and the family during the holiday season and for the tax benefit for the parents. As inductions increased in popularity, studies appeared in medical journals – almost all warning of the increased risk of cesarean with induction. At one local hospital, a nurse confided to me that so many women were being induced that it was unusual for the nurses to admit a woman in spontaneous labor. I don’t think that there is any doubt that the explosion in the number of inductions is closely tied to our skyrocketing cesarean rate.

With the growing research on the increased risks to late-preterm babies, there is finally accountability for elective inductions done before 39 weeks. In order to comply with the new Joint Commission perinatal quality measure (on elective births before 39 weeks), hospitals across the country are developing policies and protocols banning elective deliveries before 39 weeks. The NIH Conference on VBAC in March focused attention of the risks of multiple cesareans. Some OB leaders are calling for a decrease in the primary cesarean rate as the most obvious way to eliminate the risks of multiple cesareans. I am eagerly waiting the time when the obstetric profession takes the next step and reexamines the wisdom of performing elective inductions at all.

The newest induction study involved almost 8000 women who were induced both electively and for medical indications at a large community hospital (more than 7000 births each year). Researchers studied nulliparous women delivering a live, singleton, vertex pregnancy at term between May 2003 and December 2006. The obstetric staff included both teaching faculty and community providers. The researchers describe the patient population as reflecting the variability in race and ethnicity as well as socioeconomic diversity seen in the United States overall. Therefore, the patients studied approximate a population-based cohort. Although recently guidelines have been put in place at this hospital to eliminate elective induction before 39 weeks, during the time of this study, no such guidelines existed. Indications for induction were identified as fetal indications 13.6% of the cases, fetal macrosomia in 3.3%, maternal indications in 24.9%, postterm pregnancy less than 41 completed weeks of gestation in 14.3%, postterm pregnancy greater than 41 completed weeks of gestation in 18.3%, and 25.6% elective. The researchers combined elective with postterm pregnancy less than 41 weeks to come up with an overall elective rate of 39.9%. I would have also added in the inductions done for fetal macrosomia since that is not an indication recognized by ACOG (and not supported by any evidence) and since estimates of fetal weight at term are notoriously inaccurate. As in many other other studies, researchers found that the use of labor induction was associated with more than a two-fold increase in the odds of cesarean delivery.

In  conclusion, the authors wrote:

“This study has important implications for providers and their patients and emphasizes the need for women to be counseled about the potential risk of cesarean delivery with labor induction. It also predicts that efforts to reduce the use of elective labor induction might lead to a 20% decrease in the rates of cesarean delivery for a community-based population of nulliparous women.”

We agree, although we wonder if eliminating all unnecessary inductions might reduce the cesarean rate by more than 20%…

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