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

Overview

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.

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.