Oxytocin Bolus Versus Infusion in High-Risk Patients Undergoing Elective Cesarean Section (INBOX-HR)

NCT07688512 | Not Yet Recruiting Phase 4 FDA Drug

• 1 other identifier: IRB2026-00322
• Study Type: interventional
• Target: 180
• Locations: 0 countries
• Sites: N/A

Brief Summary

The goal of this randomized, double-blind clinical trial is to learn if Oxytocin is most effective at achieving adequate uterine tone (important for preventing postpartum hemorrhage) when administered as a bolus or an infusion in patients at high-risk for postpartum hemorrhage in elective cesarean sections. The main questions that will be answered are:

1. 1.Is Oxytocin bolus more effective than Oxytocin infusion at achieving adequate uterine tone at 2 minutes after the baby is born and every minute thereafter?
2. 2.Does Oxytocin bolus cause less maternal side effects than Oxytocin infusion?
3. 3.Does Oxytocin bolus result in less blood loss than Oxytocin infusion in high risk for postpartum hemorrhage patients undergoing elective cesarean sections?
4. 4.Be randomized to receive either Oxytocin bolus or Oxytocin infusion during their cesarean section but after the baby is born.
5. 5.Be asked a question about their experience 2 hours after the surgery.
6. 6.Allow the research team to collect information about how they are doing from their hospital medical records.

Conditions

Postpartum Hemorrhage; Uterine Atony; Uterine Atony With Hemorrhage; Elective Cesarean Section

Keywords

Oxytocin bolus vs infusion in elective cesarean section in patients at high risk for postpartum hemorrhage

Outcome Measures

Primary Outcomes (1)

• Time to uterine tone

  Uterine tone will be assessed at 2 mins and then every minute thereafter until adequate uterine tone is attained but no more than 10 minutes maximum, by a blinded obstetrician. Uterine tone will be deemed adequate or inadequate by the blinded obstetrician. The time for the primary endpoint analysis is adequacy of uterine tone at 2 minutes after the baby is born/umbilical cord clamped.

  2 minutes after umbilical cord clamp until 10 minutes.

Secondary Outcomes (8)

• Estimated intraoperative blood loss

  From the start to end of surgery

• Changes in heart rate (beats per minute)

  During uterine cord clamp and every 2 minutes thereafter until 10 minutes

• Changes in blood pressure (mmHg)

  During uterine cord clamp and every 2 minutes thereafter until 10 minutes.

• Total dose of phenylephrine administered intraoperatively

  From the start to end of surgery

• Participants with need for additional uterotonic agents

  From oxytocin administration until end of surgery

Study Arms (2)

Oxytocin Bolus

ACTIVE COMPARATOR

Patients in the bolus arm will receive a 3 IU oxytocin IV bolus over 15 seconds after delivery of the baby/uterine cord clamping and a maintenance infusion of 0.9% Saline will be started at 225ml/hr. If uterine tone is considered inadequate after an additional 3 minutes, a second bolus of 3 IU oxytocin is given IV over 15 seconds. If uterine tone is inadequate after an additional 3 minutes, a third bolus of 3 IU Oxytocin IV is given over 15 seconds. If after an additional 3 mins uterine tone is still inadequate, a second infusion consisting of oxytocin 3 IU/hr is started at 100ml/hrs and continued for a total of 4 hours, second line uterotonic agents (Methergine, Hemabate and/ or Cytotec) will be given, and the maintenance 0.9% Saline infusion will be changed to 450 ml/hr for a total of 1 hour, then changed to 38 ml/ hour for the following 3 hours. If uterine tone is considered adequate at 3, 6 or 9 minutes, a second infusion of oxytocin 3 IU/hr (100ml/hr) is started and maintained

Drug: Oxytocin Bolus or Oxytocin Infusion

Oxytocin Infusion

ACTIVE COMPARATOR

Patients in the infusion arm will receive a bolus of IV 0.9% Saline over 15 seconds after delivery of the baby/uterine cord clamping and a maintenance infusion of 18 IU/hr Oxytocin IV (225ml/hr). If uterine tone is considered inadequate after an additional 3 minutes, a second bolus of 0.9% Saline will be given IV over 15 seconds. If uterine tone is inadequate after an additional 3 minutes, a third bolus of 0.9% Saline will be given IV over 15 seconds. If after an additional 3 mins uterine tone is still inadequate, a second infusion of 0.9% Saline will be started at 100 ml/hr for 4 hours, second line uterotonic agents (Methergine, Hemabate and/or Cytotec) will be given, and the Oxytocin infusion will be changed to 36 IU/hour (450 ml/hr) for a total of 1 hour, and then changed to 38 ml/hr for the following 3 hours. If uterine tone is considered adequate at 3, 6 or 9 minutes, a second infusion of 0.9% Saline at 100 ml/hr will be started and maintained for 4 hours.

Drug: Oxytocin Bolus or Oxytocin Infusion

Interventions

Oxytocin Bolus or Oxytocin Infusion DRUG

On the day of surgery, patients will be randomized to receive either bolus or infusion administration of Oxytocin. On the day of the procedure, periprocedural data and patient satisfaction (single question) will be recorded.

Oxytocin Bolus; Oxytocin Infusion

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Undergoing elective cesarean section under spinal anesthesia or combined spinal anesthesia (CSE)
• Patients must be able to provide written informed consent in either English or Spanish
• Parturient classified as high risk for postpartum hemorrhage as defined by the adapted California Maternal Quality Care Obstetric Hemorrhage Risk Screen

You may not qualify if:

• Parturient in labor or ruptured membranes
• Patient does not possess the physical and mental capacity to provide informed consent
• Urgent or emergent cesarean sections
• Patients with a known major coagulopathy
• Patients with significant thrombocytopenia limiting neuraxial anesthesia (\<70k)
• Patients on therapeutic anticoagulation at time of procedure
• Patients on the placenta accreta spectrum
• Patients with severe cardiac disease contraindicating oxytocin
• Patients with an allergy to oxytocin

Sponsors & Collaborators

• Stony Brook University: lead

Related Publications (7)

• Wang LY, Wang J, Dong JH, Ping ZP, Chen XZ, Wei CN. The optimal oxytocin infusion rate for preventing uterine atony during cesarean delivery in elderly parturients with prior history of cesarean delivery. Front Pharmacol. 2023 Jul 28;14:1211693. doi: 10.3389/fphar.2023.1211693. eCollection 2023.

  PMID: 37576820 BACKGROUND

• Oyelese Y, Ananth CV. Postpartum hemorrhage: epidemiology, risk factors, and causes. Clin Obstet Gynecol. 2010 Mar;53(1):147-56. doi: 10.1097/GRF.0b013e3181cc406d.

  PMID: 20142652 BACKGROUND

• Joseph J, George SK, Daniel M, Ranjan RV. A randomised double-blind trial of minimal bolus doses of oxytocin for elective caesarean section under spinal anaesthesia: Optimal or not? Indian J Anaesth. 2020 Nov;64(11):960-964. doi: 10.4103/ija.IJA_377_20. Epub 2020 Nov 1.

  PMID: 33487681 BACKGROUND

• Fuchs AR, Fuchs F, Husslein P, Soloff MS. Oxytocin receptors in the human uterus during pregnancy and parturition. Am J Obstet Gynecol. 1984 Nov 15;150(6):734-41. doi: 10.1016/0002-9378(84)90677-x.

  PMID: 6093538 BACKGROUND

• Terblanche N, Otahal P, Messmer A, Wright P, Patel S, Nathan K, Sharman JE. An observational cohort study of 3 units versus 5 units slow intravenous bolus oxytocin in women undergoing elective caesarean delivery. J Physiol Pharmacol. 2017 Aug;68(4):547-553.

  PMID: 29151071 BACKGROUND

• Balki M, Tsen L. Oxytocin protocols for cesarean delivery. Int Anesthesiol Clin. 2014 Spring;52(2):48-66. doi: 10.1097/AIA.0000000000000016. No abstract available.

  PMID: 24667448 BACKGROUND

• Say L, Chou D, Gemmill A, Tuncalp O, Moller AB, Daniels J, Gulmezoglu AM, Temmerman M, Alkema L. Global causes of maternal death: a WHO systematic analysis. Lancet Glob Health. 2014 Jun;2(6):e323-33. doi: 10.1016/S2214-109X(14)70227-X. Epub 2014 May 5.

  PMID: 25103301 BACKGROUND

MeSH Terms

Conditions

Postpartum Hemorrhage; Uterine Inertia

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; Dystocia

Study Officials

• Tiffany E Angelo, DO, FASA

  Stony Brook University Hospital Department of Anesthesiology

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Tiffany E Angelo, DO, FASA

CONTACT

631-759-0328; tiffany.angelo@stonybrookmedicine.edu

Anna E Suske

CONTACT

631-317-8420; anna.suske@stonybrookmedicine.edu

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: Randomized, double-blinded, 2-arm, parallel study.

Study Record Dates

• First Submitted: June 24, 2026
• First Posted: July 7, 2026
• Study Start: August 1, 2026
• Primary Completion (Estimated): August 1, 2028
• Study Completion (Estimated): February 1, 2029
• Last Updated: August 3, 2026

Record last verified: 2026-06