A Phase 4 interventional study of Carbetocin and Oxytocin in Postpartum Hemorrhage, Uterine Atony and Cesarean Section, sponsored by Mansoura University. Recruiting at 1 site in Saudi Arabia. Open to female participants aged 18 Years to 45 Years. Per ClinicalTrials.gov, last updated 2026-10-09.
Sponsored by Mansoura University · Phase 4, Interventional, and Treatment
Background: Carbetocin is an established single-dose uterotonic agent for postpartum hemorrhage prophylaxis at elective cesarean delivery. Despite its proven efficacy, many clinicians routinely add a supplemental oxytocin infusion following carbetocin administration without evidence-based justification. Concurrent oxytocin receptor stimulation may be redundant, counterproductive through receptor desensitization, or incrementally beneficial - a mechanistic uncertainty that remains unresolved in the published literature.
Objectives: To determine whether carbetocin monotherapy (100 micrograms IV bolus plus placebo infusion) is non-inferior to carbetocin plus supplemental oxytocin infusion (10 IU over 4 hours) in preventing the need for additional uterotonic agents within 24 hours of elective cesarean delivery.
Study Design: Prospective, randomized, double-blind, placebo-controlled, non-inferiority trial with an integrated pilot phase. Phase 1 (Pilot, n=60) establishes local feasibility and event rate. Phase 2 (Full trial, n=332) provides the definitive non-inferiority analysis.
Participants: Women aged 18-45 years undergoing elective cesarean delivery under spinal anesthesia at Qassim University Medical City, singleton pregnancy at or beyond 37 weeks, ASA physical status II, preoperative hemoglobin 9 g/dL or more.
Interventions: Group C (Monotherapy): Carbetocin 100 micrograms IV bolus plus placebo saline infusion 500 mL over 4 hours. Group C+O (Combination): Carbetocin 100 micrograms IV bolus plus oxytocin 10 IU in 500 mL saline over 4 hours.
Primary Outcome: Proportion of patients requiring at least one additional uterotonic agent within 24 hours of delivery.
Secondary Outcomes: Quantitative intraoperative blood loss by gravimetric measurement; total 24-hour blood loss; actual blood loss by Gross formula; hemoglobin and hematocrit changes; uterine tone scores by verbal numerical rating scale (0-10) at 2, 5, and 10 minutes; incidence of postpartum hemorrhage; blood transfusion requirement; hemodynamic profiles; adverse effects.
Sample Size: 332 patients (166 per group), non-inferiority margin 10 percentage points, one-sided alpha 0.025, 80% power, estimated baseline event rate 10%, with 15% dropout allowance.
PHARMACOLOGICAL RATIONALE:
Carbetocin exerts its uterotonic effect through sustained occupancy of myometrial oxytocin receptors (OTRs). Continuous stimulation of OTRs triggers homologous receptor desensitization, progressively reducing myometrial responsiveness. The addition of an oxytocin infusion following carbetocin raises three competing hypotheses: (1) incremental benefit from residual unoccupied receptors; (2) receptor counterproductivity through accelerated downregulation; or (3) pharmacological redundancy. No published RCT has resolved this uncertainty.
TRIAL DESIGN:
The trial uses a non-inferiority design because the combination regimen is already practiced without evidence. Demonstrating non-inferiority of monotherapy would provide the first evidence to safely simplify uterotonic regimens, reduce drug costs, nursing workload, and unnecessary receptor stimulation.
BLOOD LOSS MEASUREMENT:
Intraoperative blood loss measured by gravimetric quantification: [Weight soaked materials minus Weight dry materials] divided by 1.05, plus suction canister volume, minus irrigation volume, minus amniotic fluid volume. Secondary measurement uses the Gross formula: ABL = EBV x (Hb preoperative minus Hb postoperative) divided by Hb preoperative, where EBV = body weight (kg) x 85 mL/kg.
UTERINE TONE ASSESSMENT:
Assessed using the 11-point Verbal Numerical Rating Scale (VNRS 0-10) with predefined anchor definitions, by the blinded operating obstetrician via bimanual palpation at 2, 5, and 10 minutes following carbetocin bolus. Pre-study inter-rater calibration session with intraclass correlation coefficient target of 0.80 or more.
STANDARDIZED FLUID PROTOCOL:
All patients receive a standardized intravenous fluid protocol to eliminate hemodilution as a confounding variable: spinal coload Ringer's Lactate 500 mL; intraoperative maintenance 100 mL/hour; study infusion 500 mL over 4 hours identical in both groups; postoperative Ringer's Lactate 80 mL/hour for 8 hours. Total 24-hour fluid volume recorded as a statistical covariate.
STATISTICAL ANALYSIS:
Non-inferiority declared if the upper bound of the two-sided 95% confidence interval of the risk difference does not exceed +0.10. Both per-protocol and intention-to-treat analyses performed; concordance of both required per ICH E9(R1). IRB approval: Subcommittee of Health and Bioethics Research Ethics, Qassim University, Approval No. 26-23-4, dated June 02, 2026.
469 studies on the registry are indexed under Postpartum Hemorrhage; 76 are open to participants now.
This study's planned enrollment of 332 is above the median of 148 across 360 interventional studies indexed under Postpartum Hemorrhage.
Browse Postpartum Hemorrhage studies →Mansoura University is the lead sponsor of 1,119 studies on the registry; 183 are open to participants now.
Of its 9 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Carbetocin 100 micrograms IV bolus over 1 minute immediately after cord clamping, followed by placebo infusion (500 mL 0.9% sodium chloride at 83 mL/hour over 4 hours). The infusion bag is visually identical to the active arm.
Drug: Carbetocin · Drug: Placebo Saline Infusion
Carbetocin 100 micrograms IV bolus over 1 minute immediately after cord clamping, followed by active infusion (oxytocin 10 IU in 500 mL 0.9% sodium chloride at 83 mL/hour over 4 hours).
Drug: Carbetocin · Drug: Oxytocin
Carbetocin 100 micrograms (1 mL) IV bolus administered over 1 minute immediately after umbilical cord clamping. Identical administration in both arms.
Also known as: Duratocin, Pabal
Oxytocin 10 IU added to 500 mL 0.9% sodium chloride, infused at 83 mL/hour over 4 hours, initiated within 2 minutes of carbetocin bolus. Administered in the combination arm only.
Also known as: Syntocinon
500 mL 0.9% sodium chloride infused at 83 mL/hour over 4 hours, initiated within 2 minutes of carbetocin bolus. Visually identical to the active oxytocin infusion. Administered in the monotherapy arm only.
Also known as: Normal Saline Placebo
Additional Uterotonic Requirement Within 24 Hours
Proportion of patients requiring at least one additional rescue uterotonic agent at any timepoint within 24 hours of delivery, based on clinical assessment of inadequate uterine tone or uterine atony by the attending obstetrician or anesthesiologist.
Time frame: Within 24 hours of delivery
Intraoperative Blood Loss - Gravimetric Method
Quantitative intraoperative blood loss measured by gravimetric method: weight of soaked materials minus dry materials divided by 1.05, plus suction volume, minus irrigation and amniotic fluid volumes.
Time frame: Intraoperative - from cord clamping to skin closure
Total 24-Hour Blood Loss
Cumulative blood loss combining gravimetric intraoperative measurement and weighed postoperative lochia pads at 2 and 24 hours.
Time frame: 0 to 24 hours after delivery
Actual Blood Loss - Gross Formula
Calculated using estimated blood volume multiplied by the ratio of preoperative to postoperative hemoglobin change: ABL = EBV x (Hb preoperative minus Hb postoperative) divided by Hb preoperative, where EBV = body weight in kg x 85 mL/kg.
Time frame: Preoperative baseline to 24 hours postoperatively
Hemoglobin Change
Change in venous hemoglobin concentration from preoperative baseline to 24 hours postoperatively, measured by automated complete blood count analyzer.
Time frame: Preoperative baseline to 24 hours postoperatively
Hematocrit Change
Change in hematocrit from preoperative baseline to 24 hours postoperatively, measured by automated complete blood count analyzer.
Time frame: Preoperative baseline to 24 hours postoperatively
Uterine Tone Score - Verbal Numerical Rating Scale
Uterine tone assessed by blinded obstetrician using 11-point Verbal Numerical Rating Scale (0 = completely atonic, 10 = maximally contracted) via bimanual palpation at three timepoints.
Time frame: At 2, 5, and 10 minutes after carbetocin bolus
Postpartum Hemorrhage Incidence
Proportion of patients with total blood loss of 1000 mL or more within 24 hours of delivery, measured by gravimetric quantification.
Time frame: Within 24 hours of delivery
Blood Transfusion Requirement
Proportion of patients receiving packed red blood cell transfusion and total units of packed red blood cells transfused.
Time frame: Within 24 hours of delivery
Systolic Blood Pressure
Systolic blood pressure measured by non-invasive blood pressure cuff monitoring intraoperatively and in the postanesthesia care unit.
Time frame: Every 2.5 minutes intraoperatively and every 15 minutes for 4 hours postoperatively
Heart Rate
Heart rate measured by continuous 5-lead electrocardiogram monitoring intraoperatively and in the postanesthesia care unit.
Time frame: Continuous intraoperatively and every 15 minutes for 4 hours postoperatively
Adverse Effects Incidence
Incidence and severity of drug-related adverse effects including nausea, vomiting, facial flushing, headache, chest tightness, tachycardia, hypotension, and oliguria, documented by standardized checklist.
Time frame: Within 24 hours of delivery
Plan to share: Yes — De-identified individual participant data for the primary and all secondary outcome measures will be made available upon reasonable request to the principal investigator following publication of the primary results manuscript. Requests will be reviewed and approved based on scientific merit and ethical appropriateness. Requestors will be required to sign a data access agreement.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Analytic code
Time frame: Beginning 6 months after publication of the primary results manuscript and available for 5 years thereafter
Access criteria: Researchers with a methodologically sound proposal directed to the corresponding author. A signed data access agreement is required.
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Oxytocin