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Oxytocin in Multiparous Women

Not Applicable
Not yet recruiting
Conditions
Pregnancy Related
Interventions
Registration Number
NCT06372522
Lead Sponsor
Rambam Health Care Campus
Brief Summary

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.

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.

Recruitment & Eligibility

Status
NOT_YET_RECRUITING
Sex
Female
Target Recruitment
166
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 & Design

Study Type
INTERVENTIONAL
Study Design
PARALLEL
Arm && Interventions
GroupInterventionDescription
continuous oxytocin infusionPitocin Injectable Productcontinuous oxytocin infusion - women will continue to receive a continuous oxytocin infusion from start of labor augmentation until delivery.
intermittent oxytocin infusionPitocin Injectable Productintermittent 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.
Primary Outcome Measures
NameTimeMethod
The rate of women delivering within 24 hours.During admission for delivery (assessed up to 5 days since admission to delivery room)

number of women (among those who received continues Oxytocin) who manage to deliver within 24 hours from the beginning of the induction.

Secondary Outcome Measures
NameTimeMethod
NICU admissionDuring admission for delivery

neonatal admission to ICU unit

Length of latent and active phases of labor.During admission for delivery

Time interval from admission to delivery room to delivery of fetus

neonatal outcome - 1 and 5-minute Apgar score1 and 5 minutes after delivery

apgar score measured at 1 and 5 minutes after delivery

hyponatremiaDuring admission for delivery

blood sodium lower than 135 while oxytocin admission

umbilical artery pHDuring admission for delivery

blood withdrawn from umbilical artery after delivery

The rate of instrumental and caesarean deliveries.During admission for delivery

Cesarean section and operative vaginal delivery including vacuum assisted vaginal delivery

chorioamnionitisDuring admission for delivery

Chorioamnionitis diagnosed at discretion of primary provider during the second stage of labor

obstetric anal sphincter injuries (OASIS)During admission for delivery

3rd or 4th degree perineal lacerations

post-partum hemorrhage (PPH)During admission for delivery

Estimated blood loss \>500 mL for vaginal delivery and \>1000 mL for cesarean delivery

Women's satisfaction.up to 5 days after delivery

questionnaire - satisfaction scale, with number 1 as the worst score and number 5 as the highest/best score

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