Investigating the Effect of Pulsatile Administration of Oxytocin on the Desensitization of Human Myometrium In-vitro

September 2, 2015 updated by: Samuel Lunenfeld Research Institute, Mount Sinai Hospital

Postpartum hemorrhage (PPH) is a leading cause of maternal morbidity and mortality worldwide and is caused most commonly by poor uterine muscle (myometrium) tone after delivery. The first line agent used in the prevention and treatment of PPH is oxytocin.

Women who require augmentation of labor with intravenous oxytocin because of inadequate labor progression have been shown to be at increased risk of PPH. Typically, for augmentation of labor, oxytocin is used as a continuous infusion, with no consensus on the initial dose, its increments or maximal limit. High concentration continuous oxytocin infusions are not without theirs risks, which include hyperstimulation, fetal distress, as well as uterine rupture.

Studies have shown the clinical benefits of pulsatile oxytocin delivery for labor induction and augmentation with regards to requirement of less total oxytocin, similar uterine contractility and similar rates of caesarean delivery when used for labor induction and augmentation. However, the rate of PPH as a primary outcome measure has not been investigated. Therefore we currently do not know the effect of pulsatile oxytocin delivery on the rate of PPH.

The investigators hypothesize that the effect of myometrial desensitization following pulsatile oxytocin exposure would be lower when compared to continuous oxytocin exposure. These results will help in establishing whether myometrial contractility and sensitivity to oxytocin can be better preserved by delivery of pulsatile oxytocin, rather than continuous oxytocin for labor induction and augmentation, and thereby result in less PPH.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Typically labor can be augmented by exposure to high levels of continuous oxytocin, for prolonged periods. The increased incidence of uterine atony and PPH following exogenous oxytocin administration during labor augmentation is related to myometrial oxytocin receptor desensitization to oxytocin.

Human clinical trials have shown the benefits of pulsatile oxytocin administration for labor induction and augmentation, which include requirement of less total oxytocin, similar uterine contractility and similar rates of cesarean delivery. However, the outcome of the effect on PPH is not currently known.

Characterization of the effect of pulsatile oxytocin on the desensitization of myometrium when compared to the effect of continuous oxytocin, may provide guidance for the delivery of pulsatile oxytocin for labor induction and augmentation to protect against the otherwise higher risk of PPH. Furthermore, the delivery of pulsatile oxytocin may be considered in subgroups who are already at higher risk of PPH, and require labor augmentation.

The investigators' previously validated in-vitro model provides a solid foundation for the study of myometrial contractility under controlled conditions, without any confounders that could be encountered in clinical settings.

The results of this study will provide insight into the level of desensitization of human myometrium following exposure to pulsatile oxytocin. Based on oxytocin dose-response curves after pretreatment to continuous oxytocin and pretreatment to pulsatile oxytocin, we will be able to determine the extent of desensitized myometrium following each delivery method.

Study Type

Interventional

Enrollment (Actual)

18

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Toronto, Ontario, Canada, M5G1X5
        • Mount Sinai Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years to 40 years (Child, Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • Patients who give written consent to participate in this study
  • Patients with gestational age 37-41 weeks
  • Non-laboring patients, not exposed to exogenous oxytocin
  • Patients requiring primary Cesarean delivery or first repeat Cesarean delivery

Exclusion Criteria:

  • Patients who refuse to give written informed consent
  • Patients who require general anesthesia
  • Patients who had previous uterine surgery or more than one previous Cesarean delivery
  • Patients with any condition predisposing to uterine atony and postpartum hemorrhage, such as abnormal placentation, multiple gestation, preeclampsia, macrosomia, polyhydramnios, uterine fibroids, bleeding diathesis, chorioamnionitis, or a previous history of postpartum bleeding
  • Emergency Cesarean section in labor
  • Patients on medications that could affect myometrial contractility, such as nifedipine, labetolol or magnesium sulphate.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: Control (no oxytocin) pretreatment
Physiological saline solution (PSS). Every 15-minutes, the PSS will be flushed and fresh PSS will be added.
Active Comparator: Continuous oxytocin (desensitizing) pretreatment
Continuous oxytocin 10-5M. This desensitizing treatment is based on previous experiments in our laboratory demonstrating this phenomenon (reference 25 of Internal Review). The desensitizing pretreatment mimics the clinical setting of labor augmentation. Every 15-minutes, the 10-5M oxytocin will be flushed and fresh 10-5M oxytocin will be added.
Drug: Oxytocin
Oxytocin, 100 micromolar solution
Other Names:
  • pitocin
Active Comparator: Pulsatile oxytocin pretreatment
15-minutes of 10-5M oxytocin, followed by PSS for 15-minutes, followed by 10-5M oxytocin, followed by 15-minutes PSS, and so-on, for a total duration of two-hours,
Drug: Oxytocin
Oxytocin, 100 micromolar solution
Other Names:
  • pitocin

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Motility Index
Time Frame: 8 hours

Motility index (MI) takes into account both the amplitude and frequency of the myometrial contraction. It is a calculated outcome, based on the formula: frequency/(10 x amplitude).

The analysis is undertaken by attaching myometrial strips between an isometric force transducer and the base of an organ bath chamber.
8 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Amplitude of contraction
Time Frame: 8 hours
The maximum extent of uterine muscle contraction, measured in grams (g). The analysis is undertaken by attaching myometrial strips between an isometric force transducer and the base of an organ bath chamber.
8 hours
Frequency of contraction
Time Frame: 8 hours

The number of contractions in uterine muscle (myometrium) over 10 minutes, spontaneously and in response to an agonist.

The analysis is undertaken by attaching myometrial strips between an isometric force transducer and the base of an organ bath chamber.
8 hours
Integrated area under response curve (AUC)
Time Frame: 8 hours
8 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Samuel Lunenfeld Research Institute, Mount Sinai Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

January 1, 2015

Primary Completion (Actual)

June 1, 2015

Study Completion (Actual)

June 1, 2015

Study Registration Dates

First Submitted

January 9, 2015

First Submitted That Met QC Criteria

January 9, 2015

First Posted (Estimate)

January 14, 2015

Study Record Updates

Last Update Posted (Estimate)

September 4, 2015

Last Update Submitted That Met QC Criteria

September 2, 2015

Last Verified

September 1, 2015

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 14-06

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Postpartum Hemorrhage

Clinical Trials on Oxytocin

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Malaysia

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

3
Subscribe