Exteriorization Versus In Situ Hysterotomy Repair During Cesarean: Effects on Uterine Tone

Uterine Exteriorization Versus In Situ Hysterectomy Repair During Cesarean Delivery: A Pilot Randomized Controlled Trial

During standard cesarean deliveries, there are two ways that obstetricians repair the incision on the uterus (hysterotomy after delivery of the baby. One method involves lifting the uterus out of its regular place in the abdomen to repair the incision (uterine exteriorization for repair). The second method involves leaving the uterus inside the abdomen to repair the uterus (in situ repair). Both of these methods are regularly used by obstetricians during cesarean deliveries, and it is not currently known if one has benefits over the other. Currently, surgeons use both methods, but lifting the uterus out of its place is slightly more common. In this study, participants will be randomly assigned to have one of these techniques performed during their surgery. Researchers will be investigating whether one technique or the other leads to better contraction of the uterus after delivery, less bleeding, less intra-operative nausea/vomiting, or a better patient experience than another.

Study Overview

• Status: Not yet recruiting
• Conditions: Cesarean Section; Postpartum Hemorrhage; Uterine Atony; Uterine Atony With Hemorrhage
• Intervention / Treatment: Procedure: Comparator Intervention: Exteriorization; Procedure: Test Intervention: In Situ Repair

Detailed Description

There are two methods of uterine incision (hysterotomy) repair that can be utilized intra-operatively during a cesarean section: repair of the uterus within the abdomen (in situ) or temporary exteriorization of the uterus from the abdomen to repair the hysterotomy. These two techniques have been previously compared in the literature, with outcomes that focus on intraoperative nausea/vomiting or blood loss measured as estimated blood loss or changes in hemoglobin. Postpartum hemorrhage is the leading source of maternal morbidity and mortality worldwide. Uterine atony, defined as inadequate uterine contraction to compress bleeding from the placental bed after delivery, is the leading cause of postpartum hemorrhage worldwide, accounting for upwards of 70% of cases. Early assessments of and communication about uterine tone intra-operatively during cesarean deliveries are important for predicting and managing hemorrhage. In a recent 2021 study, an 11-point (0 to 10) numeric rating scale for uterine tone, was shown to have strong interrater reliability and has since been implemented to assess uterine tone intra-operatively during cesarean sections at a number of institutions. Low uterine tone scores have been found to be tightly correlated with postpartum hemorrhage and need for blood transfusion during hospitalization. Uterine repair techniques have not yet been compared with regard to their impact on uterine tone intra-operatively, and this comparison may provide valuable information on how to optimize uterine tone through surgical technique, thereby decreasing the risk of hemorrhage and need for additional interventions. The investigators propose a pilot randomized controlled trial comparing uterine exteriorization for hysterotomy repair versus in situ repair during cesarean sections. The primary outcomes related to feasibility and acceptability will include: percent of patients approached who consented, percent of patients consented who obstetricians agreed to allow for randomization, and percent crossover from randomization arm. The primary efficacy-related outcome will be uterine tone, as reported by the surgeon intra-operatively at multiple time points following delivery of the infant. Secondary outcomes will include qualitative blood loss and use of medications to treat low uterine tone, intraoperative breakthrough pain, and nausea.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Hannah Kyllo M. Resident Physician, MD; Phone Number: 650-723-5403; Email: hkyllo@stanford.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18-55
• Undergoing cesarean section

Exclusion Criteria:

• Patient age <18 or >55
• Case urgency deemed too great for consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Uterine Exteriorization; For participants randomized to the control group (uterine exteriorization for repair), standard technique for cesarean delivery will be performed intra-operatively. At the time of hysterotomy repair, the uterus will be exteriorized from the abdomen and will be sutured closed in typical fashion. Following closure of the hysterotomy, the uterus will be returned to the abdomen. The remainder of the surgery will be performed with standard technique.	Procedure: Comparator Intervention: Exteriorization; The uterus will be temporarily exteriorized from the abdomen for repair of the hysterotomy (uterine incision) after delivery of the infant in a cesarean section.
Experimental: In Situ Repair; For participants randomized to the experimental group (in situ repair), standard technique for cesarean delivery will be performed intra-operatively. At the time of hysterotomy repair, the uterus will be left in situ and will be sutured closed in typical fashion. The remainder of the surgery will be performed with standard technique.	Procedure: Test Intervention: In Situ Repair; Repair of the hysterotomy (uterine incision) within the abdomen (in situ) after delivery of the infant during a cesarean section.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Compliance/Feasibility	Percentage of consented cesarean participants who were successfully treated as randomly allocated in each arm	Duration of the study, approximately 2 years
Efficacy Signal	Mean quantitative blood loss, analyzed after log transformation in a regression model that adjusts for cesarean group (scheduled, 1st stage, and 2nd stage)	Duration of the study, approximately 2 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Feasibility: Enrollment	Number of consented participants who underwent cesarean section and Obstetrician agreed to randomization at huddle	Duration of the study, approximately 2 years
Incidence of Intraoperative Breakthrough Pain between groups		Duration of the study, approximately 2 years
Incidence of Intraoperative Vomiting between groups		Duration of the study, approximately 2 years
Total operative time between groups	Measured in minutes from skin incision to closure	Duration of the study, approximately 2 years
Time from fetal delivery to hysterotomy closure between groups	In minutes	Duration of the study, approximately 2 years
10 Minute Uterine Tone Score between groups	Uterine tone score 10 minutes after delivery of the placenta between groups, measured on a scale of 0 to 10, with "0" representing "no tone" and "10" representing excellent tone.	Duration of the study, approximately 2 years

Collaborators and Investigators

• Sponsor: Stanford University
• Investigators: Study Director: Jess Ansari, MD, MS, Stanford University

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 1, 2029
• Study Completion (Estimated): June 1, 2029

Study Registration Dates

• First Submitted: May 19, 2026
• First Submitted That Met QC Criteria: May 19, 2026
• First Posted (Actual): May 26, 2026

Study Record Updates

• Last Update Posted (Actual): May 27, 2026
• Last Update Submitted That Met QC Criteria: May 22, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Postpartum Hemorrhage; Cesarean Delivery; Cesarean Section; Uterine Atony; Uterine Tone; Uterine Atony with Hemorrhage
• Additional Relevant MeSH Terms: Urogenital Diseases; Pathologic Processes; Female Urogenital Diseases and Pregnancy Complications; Obstetric Labor Complications; Pregnancy Complications; Hemorrhage; Puerperal Disorders; Uterine Hemorrhage; Dystocia; Pathological Conditions, Signs and Symptoms; Postpartum Hemorrhage; Uterine Inertia
• Other Study ID Numbers: 84585

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: No patient level data is anticipated to be shared with other researchers for future use after this study.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No