Recovery of Oxytocin Responsiveness in Pregnant Human Myometrial Explants After Oxytocin-Induced Desensitization: an In-vitro Analysis of Oxytocin Receptor Expression and Signaling

What Was Tested

In this not phased trial, researchers set out to test Oxytocin.

Postpartum hemorrhage (PPH) is a leading cause of maternal mortality and morbidity worldwide, and is caused most commonly by poor uterine muscle contraction after delivery of the baby and placenta.

It had eight arms (groups): Control (no oxytocin) + No recovery (no intervention), Continuous oxytocin + No recovery (active comparator), Continuous oxytocin + 30 minute recovery (active comparator), Continuous oxytocin + 60 minute recovery (active comparator) and Control (no oxytocin) + No recovery + 10-7 oxytocin (active comparator).

A control experiment will be undertaken in which the myometrial explants will be exposed to PSS for 2-hours without any oxytocin. No recovery time.

10-5M oxytocin for 2 hours. No recovery time.

10-5M oxytocin for 2 hours. After 2 hours, the solution will be drained from the organ baths, and any residual solution will be removed by washing three times with PSS. Following this, the strip will be exposed to PSS for 30 minutes.

The registry classes the interventions as drug.

More on the Plan

In current practice, upon diagnosis of failure to progress during labor augmentation, oxytocin administration is discontinued, and as long as there is no indication for immediate delivery, there is a variable duration to proceed to CD.

Due to the high likelihood of OTR desensitization in this patient population, it would be clinically relevant to determine the molecular mechanisms underlying this action.

The reason for why resensitization does not occur remains unknown, but a possible explanation is that the OTRs undergo structural and functional changes during desensitization that prohibit their recovery.

The investigators propose to use their previously established in-vitro model of labour augmentation and OTR desensitization (using pregnant human myometrium and an isometric tension recording device) to investigate the molecular mechanisms governing OTR desensitization and resensitization after stopping administration of oxytocin.

Who Took Part

Enrollment: 4 actual participants took part.

It was open to women only aged from 16 years up to 40 years.

Healthy volunteers could join, not only people with the condition.

Examples of who could join: 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.

The full record lists 4 inclusion and 6 exclusion criteria; among the exclusions: 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.

How the Study Was Run

It was run as a non-randomized, parallel-group and open-label study.

The Oxytocin group and the comparison group ran side by side rather than switching.

Everyone knew when Oxytocin was being given (open label), which is simpler to run but leaves more room for expectations to affect what is reported.

It started in 2016-08-03 with completion listed for 2023-12-31.

It ran at 1 site in Canada.

Its stated primary purpose is treatment.

What Was Measured

Researchers chose this as the main measure: Oxytocin receptor (OTR) protein expression and localization (time frame: 24 hours).

It also tracked 2 secondary outcomes, for example Oxytocin receptor (OTR) phosphorylation patterns.

What This Means in Plain Language

Put simply, this is a not phased, non-randomized trial of Oxytocin in 4 people.

Its size is small, so on its own it can only give an early look.

It ended early (terminated); no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Oxytocin compound page, all human trials.