The REDUCED trial: a cluster randomized trial for REDucing the utilization of CEsarean delivery for dystocia

To reduce cesarean delivery rates in nulliparous women, guidelines for diagnosing nonprogressive labor have been developed by the National Institute of Child Health and Human Development, the American College of Obstetricians and Gynecologists, and the Society for Maternal-Fetal Medicine. These are mainly based on data from the Consortium for Safe Labor study. The guidelines have not been tested in a clinical trial, so the efficacy and safety of this new approach is uncertain.

This study aimed to assess whether adoption of new guidelines for diagnosing nonprogressing labor would reduce cesarean delivery rates.

We conducted a cluster randomized controlled trial of a knowledge translation program of the guidelines in 26 Canadian hospitals (13 control sites and 13 intervention sites). The sites included all intrapartum care sites in Alberta that perform cesarean delivery and deliver at least 70 nulliparous women annually. The baseline period started on January 1, 2015. The intervention was initiated at the first intervention site in January 2017. The follow-up period began at the first intervention site in February 2017 and lasted till February 2020. The primary outcome was the rate of cesarean delivery in nulliparous women with vertex presentation in labor at term. The secondary outcomes included spontaneous vaginal birth and maternal and neonatal safety. The main data source for the primary and secondary outcomes was the Alberta Perinatal Health Program database. The cesarean delivery rates were assessed using repeated measures mixed effects logistic regression applied to individual births.

The analysis was based on 45,193 deliveries at intervention sites and 43,725 deliveries at control sites. There was no evidence of a decrease in the rate of cesarean delivery in association with the intervention (baseline-adjusted odds ratio, 0.94; 95% confidence interval [0.85-1.05]; P=.259). The rate of spontaneous vaginal delivery increased slightly (baseline-adjusted odds ratio, 1.10; 95% confidence interval, [1.01-1.18]; P=.024). We did not observe any differences in adverse maternal or neonatal outcomes.

Cesarean delivery rates in nulliparous women were not reduced by the application of recent guidelines for the diagnosis of nonprogressive labor. Spontaneous vaginal delivery-a secondary outcome-was increased in the intervention group. The intervention appears to be safe.