The long-awaited ARRIVE Trial was published in the August 9, 2018 edition of the New England Journal of Medicine. The American College of Obstetricians and Gynecologists (ACOG) issued a joint press release with the Society for Maternal-Fetal Medicine (SMFM) on August 8, 2018 stating that, based on the results of the ARRIVE Trial, it is reasonable to offer induction at 39 weeks to women with low-risk pregnancies who are sure of their due dates.
For the low-risk woman, routine induction at 39 weeks will turn a potential low-intervention birth with freedom to move, change positions, and choose a wide variety of comfort measures to a high-intervention birth with the laboring woman most likely in bed hooked up to IV Fluids, Pitocin, continuous electronic fetal heart rate monitoring, and probably epidural analgesia. Both the mother and baby will not get the benefit of hormones that surge in the last few days before the spontaneous onset of labor to provide protection for the fetal brain and to prepare the lungs for air breathing (Buckley, 2014). The increased costs for the necessary technology and medications required with induction as well as increased need for nursing support must be considered. In addition, there are serious concerns about the study itself:
- 50, 581 women were evaluated for eligibility for the trial. Of the 22,981 women who met eligibility criteria, 71% (16,427) declined to participate. The study authors do not describe the way in which the trial participants were different from the general population of women who gave birth in the United States in 2016; but in an accompanying editorial in the August 9, 2018 issue of the New England Journal of Medicine, Dr. Michael F. Greene describes the differences (Greene, 2018). Based on data from the National Vital Statistics Reports (Martin, et al., 2018), the trial participants were younger (median age of 23 to 24 versus a mean age of 28.7 for all U.S. mothers; were less likely to be older (only 4.1% of trial participants were 35 or older versus 17% for all mothers); and were less likely to be white and more likely to be Black or Hispanic than all mothers.
- The cesarean rates in both groups (induction group, 18.6% and expectant management group, 22.2%) were lower than the national low-risk cesarean rates of 26% in 2017; 25.7% in 2016; 25.8% in 2015; and 26% in 2014. This may have been due to the fact that providers in the trial were encouraged to allow at least 12 hours in the latent phase after completion of any cervical ripening, rupture of membranes, and administration of oxytocin before concluding the the induction had failed and deciding on cesarean surgery. Providers may not always exhibit such patience, thus increasing cesarean rates with induction.
- There are only five days difference in the median delivery date of 39.3 weeks gestation for the induction group and 40.0 weeks of gestation in the expectant management group.
- The difference in the cesarean rates between the two groups was only 3.6%. There is no information in the study about the ways in which labor was managed. There are many evidence-based strategies such as continuous support during labor that have a greater impact in reducing cesarean rates.
- There were a couple of “scheduling errors” which resulted in pregnant women having inductions before 39 0/7 weeks. For this study, the number was small, but if routine induction at 39 weeks is widely adopted, there certainly could be many more unintended early-term or even late-preterm births.
For me, the results of this study do not meet this standard set by the authors of A Guide to Effective Care in Pregnancy and Childbirth (Enkin, et al, 2000):
“Any interference with the natural process of pregnancy and childbirth should also be shown to do more good than harm.”
ACOG took an important step forward to promote normal physiologic birth with their 2017 committee opinion on limiting interventions for women with low-risk pregnancies. I believe they have taken a giant step backwards in stating that it is reasonable to offer low-risk women labor induction at 39 weeks.
You can use this chart to let students in your childbirth classes know how their experience of labor will be different if they choose induction at 39 weeks.