Oxytocin Rest to Reduce Cesarean Delivery (ORCA)

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Christiana Care Health Services




Labor Dystocia
Failed Induction
Prolonged Labor


Other: Oxytocin rest

Study type


Funder types




Details and patient eligibility


Prolonged labor is usually managed with continuous oxytocin infusion. "Oxytocin rest" has been proposed as a strategy to resolve protracted labor in patients who have received continuous oxytocin without progress. This strategy involves discontinuing oxytocin then restarting infusion after a period of time, under the theory that washout of the oxytocin receptor will strengthen uterine contractions to improve labor progress. "Oxytocin rest" is performed on labor and delivery units across the United States. Yet, there is no randomized or prospective data to support the practice. The purpose of this study is to assess whether oxytocin rest of 60 minutes in patients with prolonged labor reduces risk for cesarean delivery.

Full description

This open-label, multicenter randomized trial of consenting pregnant people with prolonged latent labor aims to determine whether 60-minute oxytocin rest reduces risk for cesarean when compared to continuous oxytocin infusion. As secondary aims, this trial will also assess the impact of 60-minute oxytocin rest on: measures of the length of labor, risk for adverse maternal and neonatal outcomes, and measures of patient autonomy and sense of control. We will enroll 350 patients with singleton pregnancies at ≥36 weeks gestation with prolonged labor in the latent phase, defined as cervical dilation <6cm after ≥8 hours since rupture of membranes and on continuous oxytocin. We will include both nulliparous and multiparous individuals undergoing induction or augmentation of labor. We will exclude patients with any contraindication to continuous oxytocin at randomization, or for whom cesarean section is anticipated at randomization. We will also exclude patients with prolonged rupture of membranes and patients with intraamniotic infection prior to randomization. Using blocked randomization via computer-generated randomization scheme, subjects will be randomized with equal probability to 60-minute oxytocin rest or usual care with continuous oxytocin. Trial participants and their health care team will be aware of their assignment. Participants in the intervention group will undergo 60-minute oxytocin rest. With the permission of the clinical team, they will be able to break from continuous fetal monitoring to rest, shower, walk, or eat during this time. After 60 minutes, oxytocin will be restarted at 2 mU/min and subsequently increased by 2 mU/min every 30 minutes to a maximum dose of 30 mU/min or until adequate contractions are seen. Subjects in the control group will receive continuous oxytocin infusion, increased by 2 mU/min every 30 minutes to a maximum dose of 30 mU/min or until adequate contractions are noted. The remainder of labor care will be at the discretion of the clinical team. Prior to hospital discharge, demographic and clinical data from each participant and their infant will be obtained via chart review. We are planning for the trial to take place at three institutions. Our primary site will be ChristianaCare Health System.


350 estimated patients




18 to 55 years old


No Healthy Volunteers

Inclusion criteria

  • ≥18 years of age
  • Singleton gestation in vertex presentation
  • ≥36 weeks gestation
  • Prolonged latent labor, defined as cervical dilation <6cm after ≥8 hours since rupture of membranes and on continuous oxytocin

Exclusion criteria

  • Not meeting the above criteria
  • Any contraindication to continuous oxytocin at time of randomization
  • Cesarean section anticipated by the clinical team at time of randomization (for any reason excepting labor dystocia)
  • >18 hours between rupture of membranes and randomization
  • Known intraamniotic infection at randomization
  • Fetal demise
  • Any contraindication to vaginal delivery
  • Maternal eclampsia

Trial design

Primary purpose




Interventional model

Parallel Assignment


None (Open label)

350 participants in 2 patient groups

60-minute oxytocin rest
Experimental group
Other: Oxytocin rest
Usual care with continuous oxytocin infusion
No Intervention group

Trial documents

Trial contacts and locations



Central trial contact

Teresa C Logue

Data sourced from clinicaltrials.gov

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