Oxytocin Rest to Reduce Cesarean Delivery (ORCA)

Oxytocin Rest to Reduce Cesarean Delivery in Prolonged Labor: An Open-Label, Randomized Controlled Trial

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.

Study Overview

• Status: Recruiting
• Conditions: Prolonged Labor; Failed Induction; Labor Dystocia
• Intervention / Treatment: Other: Oxytocin rest

Detailed Description

This open-label 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.

The investigators 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. Both nulliparous and multiparous individuals undergoing induction or augmentation of labor will be included. Patients with any contraindication to continuous oxytocin at randomization, or for whom cesarean section is anticipated at randomization will be excluded. Patients with prolonged rupture of membranes and patients with intraamniotic infection prior to randomization will also be excluded.

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.

The primary site for the trial will be ChristianaCare Health System.

• Study Type: Interventional
• Enrollment (Estimated): 350
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Teresa C Logue; Phone Number: (302)-733-6563; Email: teresa.logue@christianacare.org

Study Locations

• United States
  • Delaware
    • Newark, Delaware, United States, 19718
      • Recruiting
      • ChristianaCare Health System
      • Contact: Teresa C Logue; Phone Number: 302-733-6563; Email: teresa.logue@christianacare.org

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 60-minute oxytocin rest	Other: Oxytocin rest; 60-minute oxytocin rest; Other Names: pit rest
No Intervention: Usual care with continuous oxytocin infusion

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cesarean rate	Number of participants delivered by cesarean	At time of delivery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to delivery (hours)	defined as time from enrollment to delivery time, regardless of mode of delivery	From randomization to delivery
Time to vaginal delivery (hours)	defined as time from enrollment to delivery time, for patients with vaginal delivery (cesarean delivery censored)	From randomization to delivery
Time to active labor (hours)	defined as time from enrollment to first exam with cervical dilation ≥6cm (cesarean delivery at <6cm dilation censored)	From randomization to delivery
Duration of active labor (hours)	defined as time from first exam with cervical dilation ≥6cm to delivery time (cesarean delivery censored)	From randomization to delivery
Composite maternal adverse outcome	to include operative vaginal delivery, obstetric anal sphincter injury, postpartum wound complications (wound cellulitis requiring antibiotics, wound reopened for fluid collection or infection, wound dehiscence), intraamniotic infection, postpartum endometritis, postpartum hemorrhage, deep vein thrombosis (DVT)/pulmonary embolism (PE), ICU admission, maternal death	From date of delivery to date of hospital discharge for mother, expected average of 3 days
Composite neonatal adverse outcome	to include NICU admission ≥48 hours, APGAR score at 5 minutes <7, cord pH <7.00, intubation and mechanical ventilation ≥12 hours, neonatal sepsis, hypoxic ischemic encephalopathy, stillbirth or neonatal death	From date of delivery to date of hospital discharge for neonate (or up to 28 days of life)
Rate of intraamniotic infection (IAI)	defined as maternal temperature ≥ 38.0°C in the intrapartum period and initiation of antibiotics in the intrapartum period	From randomization to delivery
Rate of postpartum endometritis	defined as maternal temperature ≥ 38.0°C in the postpartum period AND initiation of antibiotics in the postpartum period	From date of delivery to date of hospital discharge for mother, expected average of 3 days
Rate of postpartum hemorrhage	defined as quantitative blood loss ≥ 1000 mL (preferred) OR estimated blood loss ≥ 1000 mL (if QBL not performed or not available)	From date of delivery to date of hospital discharge for mother, expected average of 3 days
Labor Agentry Scale score	The LAS is a validated tool that captures patient perception of control over the labor process. It will be administered to all enrolled patients between 6 and 96 hours after delivery. The scale asks subjects to rate their agreement with multiple statements about the labor process from 1 (almost always) to 7 (rarely), with interpretation of ratings varying by statement.	From date of delivery to date of hospital discharge for mother, expected average of 3 days

Collaborators and Investigators

• Sponsor: Christiana Care Health Services
• Investigators: Principal Investigator: Teresa C Logue, Christiana Care Health Services; Principal Investigator: Matthew K Hoffman, Christiana Care Health Services

Study record dates

Study Major Dates

• Study Start (Actual): March 19, 2024
• Primary Completion (Estimated): February 15, 2026
• Study Completion (Estimated): March 15, 2026

Study Registration Dates

• First Submitted: February 13, 2024
• First Submitted That Met QC Criteria: February 13, 2024
• First Posted (Actual): February 20, 2024

Study Record Updates

• Last Update Posted (Actual): October 17, 2024
• Last Update Submitted That Met QC Criteria: October 15, 2024
• Last Verified: October 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pregnancy Complications; Obstetric Labor Complications; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Dystocia; Physiological Effects of Drugs; Reproductive Control Agents; Oxytocics; Oxytocin
• Other Study ID Numbers: 43084

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No