Preventive Induction of Labor: Can Its Use Lower the Cesarean Delivery Rate?

The cesarean delivery rate in the United States has risen from 5.5% in 1970 to reach its highest level yet of 31.8% in 2007. ^1,2 Thus, at 1.2 million surgeries per year, cesarean delivery is the most common major surgery performed, essentially twice the goal of 15% from Healthy People 2010. ³ In addition, primary cesarean deliveries, which accounted for 20.6% of all deliveries in 2004, continue to climb, increasing by 5% annually, ⁴ and it appears the old adage, once a cesarean, always a cesarean, is true for >90% of women. ⁵ Because the rate of vaginal birth after cesarean (VBAC) has fallen to its lowest level in 20 years as well, this means that the overall rate of cesarean delivery is only likely to continue to rise.

Why is the cesarean delivery rate rising? Although maternal obesity and weight gain during pregnancy are increasing, ⁶ as is birth weight ⁷ and other maternal characteristics associated with an increased rate of cesarean delivery, the bulk of the rise in cesarean delivery does not appear to be related to these factors. ⁸ Some authors have promoted that women are choosing more cesarean sections, ⁹ but this does not account for most of the rise either. ¹⁰ It appears that the primary cause for the rise is a change in the culture of obstetrics, which increasingly relies on cesarean delivery to prevent rare neonatal complications, warding off lawsuits. ¹¹

This rapid rise in cesarean deliveries is particularly concerning because cesarean delivery is associated with higher rates of maternal hemorrhage, wound and uterine infections, and even death compared with vaginal delivery. ^{12 –14} Additionally, a current cesarean delivery impacts maternal and neonatal outcomes in subsequent pregnancies. ^15,16 In particular, multiple cesareans are associated with placenta previa and accreta, ¹⁷ which, in turn, are both associated with preterm delivery, maternal hemorrhage, and mortality. ¹⁸

One management scheme that may be used by providers and patients interested in increasing the chances of vaginal birth while affording more control to the parturient with respect to scheduling is elective or preventive induction of labor. Although elective induction of labor has traditionally been thought to increase the risk of cesarean delivery, the bulk of the evidence to this effect is based on flawed observational studies. ^{19 –21} Interestingly, prospective, randomized controlled trials (RCTs) conducted at 41 weeks and beyond find a lower rate of cesarean delivery in women induced compared with those undergoing expectant management of the pregnancy. ^22,23 This finding persists in three prospective trials conducted prior to 41 weeks of gestation as well. ²⁴ The disagreement between the observational and prospective literature appears to be primarily because observational studies compare women undergoing induction of labor with those experiencing spontaneous labor, whereas most prospective RCTs compare induction of labor with expectant management of the pregnancy. Expectant management allows women to progress to a greater gestational age, which may lead to spontaneous labor at the greater gestational age or induction of labor at the greater gestational age. ²⁵ Of note, the risk of cesarean delivery generally rises throughout the term pregnancy by week of gestation. ^26,27

To combat the rising rate of cesarean delivery, Nicholson et al. ²⁸ described a specific preventive induction of labor termed Active Management of Risk in Pregnancy at Term (AMOR-IPAT) in 2004. Through identification of women at higher risk for cephalopelvic disproportion or fetal intolerance of labor, they describe a protocol of preventive induction of labor, commonly between 38 and 40 weeks of gestation, which in the study population led to lower rates of cesarean delivery. In this issue of the Journal of Women's Health, they replicate their prior work. ²⁹ Again, they demonstrate lower rates of cesarean delivery as well as lower rates of some measures of maternal and neonatal morbidity, without concomitant rise in any of the complications. Of note, in a small pilot study using a prospective RCT study design, Nicholson et al. ³⁰ demonstrated similar findings with improved neonatal outcomes and a trend toward a lower cesarean rate.

Hopefully, the work by Nicholson et al. will be supported by other, larger, prospective trials. If their studies and those of others support the use of scheduled induction of labor to actually lower the cesarean delivery rate, this may provide a tool for obstetricians and midwives to decrease both the maternal and neonatal complications in term pregnancies. One issue with the AMOR-IPAT approach is that the somewhat complicated calculation sheet may not be readily used by clinicians in a busy clinic. It could be incorporated quite easily into an electronic medical record, however, which would instantaneously provide a clinician with the upper limit of the optimal time for delivery based on the AMOR-IPAT calculations.

The preventive induction approach will only work in an environment that disallows cesarean delivery for failed induction. This means that all women who undergo induction of labor are managed with prostaglandins, Foley bulb, oxytocin, or artificial rupture of the membranes (AROM) as well as provider patience until they achieve active labor. Such inductions can be time consuming and occupy valuable space on labor and delivery units. The approach by Nicholson et al. is for such preventive inductions of labor to replace elective inductions of labor. Hopefully, this will allow better control of labor and delivery volume and more efficient staffing. Further, as induction of labor does appear to be more costly than spontaneous labor or elective cesarean section, ³¹ cost-effectiveness studies of this issue should be conducted.

The preventive medicine approach to prevention of cesarean delivery and complications of term pregnancies that focuses on those women who are most likely to benefit from intervention is both thoughtful and innovative. Although there are certainly concerns about misuse of preventive induction of labor and mismanagement of labor inductions, this intervention may be one solution to the current cesarean delivery epidemic. It allays fears of term complications while giving women control over their timing of labor. It is my hope that this approach will be validated and the translation of these findings to actual use by clinicians can begin.

Disclosure Statement

The author has no conflicts of interest to report.