Committee on Obstetric Practice
Committee on Practice Bulletins—Obstetrics
This Practice Advisory was developed by the American College of Obstetricians and Gynecologists’ Committee on Obstetric Practice and Committee on Practice Bulletins—Obstetrics in collaboration with Mark Turrentine, MD and Yasser El-Sayed, MD.
The American College of Obstetricians and Gynecologists endorses the Society for Maternal-Fetal Medicine statement on the ARRIVE trial.
A randomized controlled trial comparing elective induction of labor at 39 weeks gestation with expectant management among low-risk nulliparous women was published in the New England Journal of Medicine on August 8, 2018 1. The study was a large unmasked multicenter trial conducted from March 2014 to August 2017 that approached 22,533 eligible women, of which 6,106 (27%) provided informed consent and underwent randomization. The trial was conducted at 41 facilities across the United States consisting of university and community hospitals. Greater than 94% of subjects adhered to the assigned protocol, with 62.7% in the induction group and 64.2 % in the expectant management group having a Bishop score < 5 at the time of randomization.
This study demonstrated no statistical difference in the primary composite outcome of perinatal mortality and severe perinatal morbidity (Relative Risk [RR] 0.80, 95% Confidence Interval [95% CI] 0.64 to 1.00; P =0.049). A P-value of < 0.046 indicated statistical significance for the primary perinatal outcome 1. The pre-specified major maternal outcome was cesarean delivery rate; this was noted to be significantly lower in the induction of labor group (18.6% versus 22.2%, RR 0.84, 95% CI 0.76 to 0.93; P = < 0.001). Analysis of other secondary outcomes noted significantly lower rates in the induction of labor group of gestational hypertension and preeclampsia (9.1% versus 14.1%, RR 0.64, 95% CI 0.56 to 0.74, P = < 0.001), as well as need for neonatal respiratory support within the first 72 hours of life (3.0% versus 4.2%, RR 0.71, 95% CI 0.55 to 0.93). No other differences in perinatal or maternal outcomes were detected. Additionally, for prespecified subgroup analyses of the primary perinatal outcome and Cesarean delivery, no significant differences were noted according to race or ethnic group, maternal age, body-mass index, or modified Bishop score. Based on these results, the authors suggest that policies aimed at the avoidance of elective labor induction among low-risk nulliparous women at 39 weeks of gestation are unlikely to reduce the rate of cesarean delivery on a population level 1.
Based on the findings demonstrated in this trial, it is reasonable for obstetricians and health-care facilities to offer elective induction of labor to low-risk nulliparous women at 39 weeks gestation. However, consideration for enactment of this elective induction of labor intervention should not only take into account the trial findings, but that this recommendation may be conditional upon the values and preferences of the pregnant woman, the resources available (including personnel), and the setting in which the intervention will be implemented. A collaborative discussion with shared-decision making should take place with the pregnant woman. Additionally, as induction of labor involves coordination between the health care provider and the infrastructure in which induction and delivery will occur, it is critical that personnel and facilities coordinate polices related to the offering of elective induction of labor.
As in the case with any induction of labor – irrespective of whether it is medically indicated or elective – care should be taken to minimize perinatal morbidity and reduce the chance of a primary cesarean birth. Nonintervention in the latent phase when the maternal and fetal conditions permit is paramount. Current guidance from the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine recommends that if the maternal and fetal status allow, cesarean births for failed induction of labor in the latent phase can be avoided by allowing longer durations of the latent phase (up to 24 hours or longer) and requiring that oxytocin be administered for at least 12–18 hours after membrane rupture before deeming the induction a failure 2. Additional information from planned secondary-analysis from this trial will need to be evaluated to assess the impact this intervention has on health care expenditures. A nonmedically indicated early-term birth (before 39 0/7 weeks of gestation) is not appropriate 3.