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

Randomized Double-Blinded Clinical Trial of Oxytocin Bolus Versus Infusion in High-Risk Patients Undergoing Elective Cesarean Section

Status
Not yet recruiting
Phases
Phase 4
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07688512
Acronym
INBOX-HR
Enrollment
180
Registered
2026-07-07
Start date
2026-08-01
Completion date
2029-02-01
Last updated
2026-08-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

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

Keywords

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

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. 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. Does Oxytocin bolus cause less maternal side effects than Oxytocin infusion? 3. Does Oxytocin bolus result in less blood loss than Oxytocin infusion in high risk for postpartum hemorrhage patients undergoing elective cesarean sections? 3\. Are patients more satisfied with their cesarean section when they receive Oxytocin bolus or Oxytocin infusion? Researchers will compare the 2 methods of Oxytocin administration, bolus versus infusion, to see which method is more effective or if they are equally effective. Participants will: 1. Be randomized to receive either Oxytocin bolus or Oxytocin infusion during their cesarean section but after the baby is born. 2. Be asked a question about their experience 2 hours after the surgery. 3. Allow the research team to collect information about how they are doing from their hospital medical records.

Detailed description

Oxytocin is the most commonly used uterotonic agent worldwide to achieve adequate uterine tone and prevent postpartum hemorrhage. Over the past decade, the trend has been towards lowering the dose to reduce oxytocin-related adverse effects including nausea, hypotension, chest pain, EKG changes, and maternal death. However, the optimal strategy for oxytocin administration remains controversial. A prior study was conducted at Stony Brook University Hospital which investigated the difference between bolus versus infusion administration of oxytocin in elective cesarean section patients with a low risk of postpartum hemorrhage (PPH); the results of this randomized, double blinded clinical trial showed that bolus was not superior for adequate uterine tone at 2 minutes when compared to infusion of oxytocin, but blood loss was modestly lower and total oxytocin exposure was substantially lower in the bolus arm. Which makes the most logical next question: Does bolus oxytocin become more clinically meaningful in patients with higher baseline risk for uterine atony or hemorrhage. The investigators aim to address this question with the INBOX-HR study. INBOX-HR acts as a continuing investigation on the difference between bolus versus infusion administration of oxytocin, specifically for patients that are at a high risk for postpartum hemorrhage. Thus, the purpose of this research study is to compare bolus and infusion administration of oxytocin on parturients at high risk for postpartum hemorrhage undergoing elective cesarean section. The primary objective of this study is to test the hypothesis that administration by bolus vs. infusion results in more rapid achievement of adequate uterine tone in this patient population. Secondary objectives include determining estimated blood loss, prevalence of hypotension, change in heart rate, nausea, vomiting, and patient satisfaction, and 0 - 10 uterine tone score.

Interventions

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.

Sponsors

Stony Brook University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
TRIPLE (Subject, Caregiver, Investigator)

Intervention model description

Randomized, double-blinded, 2-arm, parallel study.

Eligibility

Sex/Gender
FEMALE
Age
18 Years to 45 Years
Healthy volunteers
No

Inclusion criteria

* 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

Exclusion criteria

* 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

Design outcomes

Primary

MeasureTime frameDescription
Time to uterine tone2 minutes after umbilical cord clamp until 10 minutes.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.

Secondary

MeasureTime frameDescription
Estimated intraoperative blood lossFrom 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 intraoperativelyFrom the start to end of surgery
Participants with need for additional uterotonic agentsFrom oxytocin administration until end of surgerySuch as Methergine, Hemabate, and Cytotec
0-10 Uterine tone score2 minutes after uterine cord clamping until 10 minutes.Uterine tone score will be assessed at 2 mins and then every minute thereafter.
Participants with maternal side effectsFrom oxytocin administration until end of surgeryChest pain, nausea, vomiting
Patient satisfaction questionnaire2 hours after surgeryThe patient will be asked a question about their experience on a scale of 0-10 (0 being complete dissatisfaction, and 10 being highly satisfied).

Contacts

CONTACTTiffany E Angelo, DO, FASA
tiffany.angelo@stonybrookmedicine.edu631-759-0328
CONTACTAnna E Suske
anna.suske@stonybrookmedicine.edu631-317-8420
PRINCIPAL_INVESTIGATORTiffany E Angelo, DO, FASA

Stony Brook University Hospital Department of Anesthesiology

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Aug 4, 2026