Oxytocin in Multiparous Women

Continuous Versus Intermittent Oxytocin Infusion for Induction of Labor in Multiparous Pregnant Women

This is a randomized controlled trial investigating whether continuous oxytocin infusion in multiparous women shortens time to delivery, without altering maternal or neonatal outcomes, in augmented deliveries, compared to intermittent infusion.

Study Overview

• Status: Not yet recruiting
• Conditions: Pregnancy Related
• Intervention / Treatment: Drug: Pitocin Injectable Product

Detailed Description

Induction of labor (IOL) is defined as an artificial initiation of uterine contractions before the spontaneous onset of labor. It is indicated when maternal or fetal risks associated with continuation of pregnancy outweigh the risks associated with early delivery. Augmentation of labor refers to the stimulation of spontaneous but inadequate contractions. In high-income countries, up to 25% of all deliveries at term involve IOL.

Bishop score is a scoring system which measures changes in the cervix. It is based on several characteristics such as cervical effacement, dilatation, consistency, position and fetus head station. A Bishop score < 6 is often referred to as an unripe cervix (unfavorable), whereas ≥ 6 is referred to as a rip cervix (favorable).

Oxytocin is a commonly used drug for IOL, especially in a favorable cervix. It is a mammalian neuro-hypophyseal hormone and is used to generate regular coordinated contractions originating from the fundus towards the cervix. It is administered intravenously (IV) as an increasing infusion, titrated to the strength and frequency of uterine contractions.

There is voluminous experience with oxytocin, and it is considered as a safe drug. Although, there are several case reports reporting rare serious side effects such as: iatrogenic hyponatremia, grand mal seizure and coma, and maternal death. In a prospective observational study of 287 women at term, demonstrated that hyponatremia was correlated significantly with fluid infusion during labor, and not to oxytocin administration.

There is conflicting evidence whether oxytocin infusion should be continued during the active phase of labor or not. Prolonged administration of oxytocin may increase the risk of tachysystole and uterine rupture, which may result in fetal non-reassuring heart rate and caesarian deliveries. Conversely, discontinuing oxytocin infusion after a few hours may have an effect on time to delivery interval, duration of rupture of membrane (ROM) and chorioamnionitis.

one study had shown in an in vitro study that continuous exposure of human myometrial cells to oxytocin led to a loss of responsiveness to oxytocin. Another study, examined myometrial cell cultures from women undergoing cesarean delivery (emergent and elective). They showed that pretreatment of the cells with oxytocin resulted in a decrease in the percentage of myometrial cells that responded to subsequent oxytocin exposure. They found that preliminary exposure of 4.2 hours to oxytocin yielded half-inactivation to the second exposure.

the investigators have previously investigated whether oxytocin infusion duration increases 24-hour delivery rates and affects time to delivery length and patient's experience in nulliparous women. The investigators' results showed that continuous infusion of oxytocin for labor induction in nulliparous women with a favorable cervix may be superior over intermittent oxytocin infusion, since it shortens time-to delivery, decreases chorioamnionitis rate and improves maternal satisfaction, without affecting adverse maternal or neonatal outcomes.

In this study, the investigators' aim is to investigate whether continuous administration of oxytocin is superior to intermittent administration also in multiparous women, in terms of time to delivery and the percentage of women delivering within 24 hours.

• Study Type: Interventional
• Enrollment (Estimated): 166
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• multiparous women (women who have given birth one or more times in the past) with a singleton pregnancy that are admitted for induction of labor.
• Women at gestational age of 370/7 or more.
• Vertex presentation.

Exclusion Criteria:

• Age 18 and under.
• High order gestation.
• Women with contraindication for vaginal delivery.
• Previous cesarean delivery.
• Active labor.
• Documented fetal anomalies.

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: continuous oxytocin infusion; continuous oxytocin infusion - women will continue to receive a continuous oxytocin infusion from start of labor augmentation until delivery.	Drug: Pitocin Injectable Product; The primary dose of oxytocin is 1.0 mU/min, with an incremental increase by 2.5 mU/min every 30 minutes, until 20.0 mU/min, tittered to a target of 3-5 contractions in a 10-minute period, or active labor (dilatation > 6 cm).; Other Names: Synthetic Oxytocin
Active Comparator: intermittent oxytocin infusion; intermittent oxytocin infusion - oxytocin transfusion will be discontinued after 8 hours if the woman does not go into active labor, or does not deliver in that period of time. The second course of oxytocin will be renewed after 6 hours if the woman hasn't progressed into labor or hasn't given birth yet.	Drug: Pitocin Injectable Product; The primary dose of oxytocin is 1.0 mU/min, with an incremental increase by 2.5 mU/min every 30 minutes, until 20.0 mU/min, tittered to a target of 3-5 contractions in a 10-minute period, or active labor (dilatation > 6 cm).; Other Names: Synthetic Oxytocin

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The rate of women delivering within 24 hours.	number of women (among those who received continues Oxytocin) who manage to deliver within 24 hours from the beginning of the induction.	During admission for delivery (assessed up to 5 days since admission to delivery room)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Length of latent and active phases of labor.	Time interval from admission to delivery room to delivery of fetus	During admission for delivery
The rate of instrumental and caesarean deliveries.	Cesarean section and operative vaginal delivery including vacuum assisted vaginal delivery	During admission for delivery
chorioamnionitis	Chorioamnionitis diagnosed at discretion of primary provider during the second stage of labor	During admission for delivery
obstetric anal sphincter injuries (OASIS)	3rd or 4th degree perineal lacerations	During admission for delivery
hyponatremia	blood sodium lower than 135 while oxytocin admission	During admission for delivery
post-partum hemorrhage (PPH)	Estimated blood loss >500 mL for vaginal delivery and >1000 mL for cesarean delivery	During admission for delivery
neonatal outcome - 1 and 5-minute Apgar score	apgar score measured at 1 and 5 minutes after delivery	1 and 5 minutes after delivery
umbilical artery pH	blood withdrawn from umbilical artery after delivery	During admission for delivery
NICU admission	neonatal admission to ICU unit	During admission for delivery
Women's satisfaction.	questionnaire - satisfaction scale, with number 1 as the worst score and number 5 as the highest/best score	up to 5 days after delivery

Collaborators and Investigators

• Sponsor: Rambam Health Care Campus

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2024
• Primary Completion (Estimated): April 1, 2026
• Study Completion (Estimated): April 1, 2027

Study Registration Dates

• First Submitted: February 28, 2024
• First Submitted That Met QC Criteria: April 17, 2024
• First Posted (Actual): April 18, 2024

Study Record Updates

• Last Update Posted (Actual): April 18, 2024
• Last Update Submitted That Met QC Criteria: April 17, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Reproductive Control Agents; Oxytocics; Oxytocin
• Other Study ID Numbers: RMB-0517-23

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
• product manufactured in and exported from the U.S.: No