Oxytocin Maintenance Infusion in Labouring Women Undergoing Cesarean Delivery: an Up-down Sequential Allocation Study

NCT05290129 | Recruiting

• 1 other identifier: 22-02
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

This study is designed to determine the minimal effective oxytocin maintenance infusion required in labouring women undergoing cesarean delivery to achieve the best effect. Oxytocin is a drug that is routinely used to help the uterus to contract and keep it contracted after delivery. Consequently, it will help to reduce blood loss after delivery. In order to determine the minimal effective dose, the investigators will conduct a dose-finding study. The first patient will receive a set oxytocin infusion. The next patient's infusion dose of oxytocin, will either increase or decrease, depending on how the previous patient responds in terms of uterine tone. If the response is satisfactory with the infusion dose used, the next patient will either receive the same infusion dose or it will be decreased depending on a probability of 1:9. If the response is not satisfactory, then the infusion dose will increase for the next patient. The dose for each patient will be determined based on the results of the uterine contraction of the previous patient. The investigators hypothesize that the ED90 of the oxytocin infusion rate to maintain adequate uterine tone in labouring women with induced or augmented labour undergoing cesarean delivery, following an initial effective bolus dose, would be lower than 0.74 IU/min (44 IU/h), which was found as the ED90 in a previous study, without an initial bolus dose prior to the infusion.

Conditions

Postpartum Hemorrhage

Keywords

Cesarean delivery; oxytocin; uterotonic; pregnancy; labour

Outcome Measures

Primary Outcomes (1)

• Uterine tone up to discharge from the post anesthetic care unit (PACU): questionnaire

  Uterine tone will be evaluated as satisfactory or unsatisfactory by the obstetrician throughout the surgery, starting at 5 minutes after the oxytocin infusion. It will also be measured at 10 minutes following the oxytocin infusion and every 10 minutes following that for the duration of the surgery. Unsatisfactory uterine tone at any time until discharge from the PACU will be considered a failure of the maintenance infusion.

  2 hours

Secondary Outcomes (18)

• Calculated blood loss

  24 hours

• Need for blood transfusion

  24 hours

• Episodes of bleeding postpartum

  24 hours

• Intraoperative requirement for additional uterotonic medication

  1 hour

• Requirement for additional uterotonic medication in the PACU

  2 hours

Study Arms (10)

Oxytocin infusion rate 4 IU/h

EXPERIMENTAL

The maintenance infusion rate of oxytocin will be 4 IU/h.

Drug: Oxytocin

Oxytocin infusion rate 6 IU/h

EXPERIMENTAL

The maintenance infusion rate of oxytocin will be 6 IU/h.

Drug: Oxytocin

Oxytocin infusion rate 10 IU/h

EXPERIMENTAL

The maintenance infusion rate of oxytocin will be 10 IU/h.

Drug: Oxytocin

Oxytocin infusion rate 14 IU/h

EXPERIMENTAL

The maintenance infusion rate of oxytocin will be 14 IU/h.

Drug: Oxytocin

Oxytocin infusion rate 18 IU/h

EXPERIMENTAL

The maintenance infusion rate of oxytocin will be 18 IU/h.

Drug: Oxytocin

Oxytocin infusion rate 22 IU/h

EXPERIMENTAL

The maintenance infusion rate of oxytocin will be 22 IU/h.

Drug: Oxytocin

Oxytocin infusion rate 26 IU/h

EXPERIMENTAL

The maintenance infusion rate of oxytocin will be 26 IU/h.

Drug: Oxytocin

Oxytocin infusion rate 30 IU/h

EXPERIMENTAL

The maintenance infusion rate of oxytocin will be 30 IU/h.

Drug: Oxytocin

Oxytocin infusion rate 34 IU/h

EXPERIMENTAL

The maintenance infusion rate of oxytocin will be 34 IU/h.

Drug: Oxytocin

Oxytocin infusion rate 36 IU/h

EXPERIMENTAL

The maintenance infusion rate of oxytocin will be 36 IU/h.

Drug: Oxytocin

Interventions

Oxytocin DRUG

Oxytocin will be prepared in a 1L bag of Ringer's lactate, to be infused at a rate of 125 ml/h.

Also known as: Pitocin

Oxytocin infusion rate 10 IU/h; Oxytocin infusion rate 14 IU/h; Oxytocin infusion rate 18 IU/h; Oxytocin infusion rate 22 IU/h; Oxytocin infusion rate 26 IU/h; Oxytocin infusion rate 30 IU/h; Oxytocin infusion rate 34 IU/h; Oxytocin infusion rate 36 IU/h; Oxytocin infusion rate 4 IU/h; Oxytocin infusion rate 6 IU/h

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• All patients with induced or augmented labour undergoing cesarean delivery under neuraxial anesthesia (at least 3 hours of prior exposure to oxytocin during labour)

You may not qualify if:

• All patients who refuse to give written informed consent
• All patients who declare allergy or hypersensitivity to oxytocin
• A history of hypertension and/or severe cardiac disease(s)
• All patients who have contraindications for neuraxial anesthesia
• All patients who will be converted to general anesthesia intraoperatively
• All patients with placenta previa and multiple gestation

Sponsors & Collaborators

• Samuel Lunenfeld Research Institute, Mount Sinai Hospital: lead

Study Sites (1)

Mount Sinai Hospital

Toronto, Ontario, M5G1X5, Canada

RECRUITING

MeSH Terms

Conditions

Postpartum Hemorrhage

Interventions

Oxytocin

Condition Hierarchy (Ancestors)

Obstetric Labor Complications; Pregnancy Complications; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Puerperal Disorders; Uterine Hemorrhage; Hemorrhage; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Pituitary Hormones, Posterior; Pituitary Hormones; Peptide Hormones; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists; Peptides; Amino Acids, Peptides, and Proteins

Study Officials

• Mrinalini Balki, MD

  MOUNT SINAI HOSPITAL

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Mrinalini Balki, MD

CONTACT

416-586-4800; mrinalini.balki@uhn.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Biased coin up-and-down design.

Study Record Dates

• First Submitted: March 11, 2022
• First Posted: March 22, 2022
• Study Start: August 17, 2022
• Primary Completion: December 1, 2025
• Study Completion: December 1, 2025
• Last Updated: June 5, 2025

Record last verified: 2025-05

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)