Project Summary Cesarean sections are the most common surgery in the world. In the US alone, 3,000 are performed each day. Postpartum hemorrhage (PPH) remains the leading cause of preventable maternal mortality worldwide, accounting for 27% of the 295,000 maternal deaths worldwide, and 11% of maternal deaths in the United States. PPH is also the leading cause of severe maternal morbidity, resulting in both short and long-term consequences to a new mother’s physical and psychological health. Despite efforts at reduction, the rates of PPH increased by 13% in the US between 2010 and 2014 with atony-related hemorrhage, when the uterus fails to contract after birth, accounting for 80% of cases. The vast majority of these cases are deemed preventable. In the US, data shows that black women have significantly higher rates of severe mortality and morbidity associated with PPH – contributing to a widening health disparity. Compared to vaginal birth, women undergoing cesarean delivery incur the highest risk of PPH, hemorrhage-related morbidity, and cost to the healthcare system. Prophylactic administration of oxytocin has been shown to reduce the incidence of PPH by 50- 60%, however, there are not clear recommendations for oxytocin dosing regimens and the most appropriate approach to prophylactic dosing at CD continues to be actively investigated as larger doses may be required but there can be significant hemodynamic changes after IV boluses of oxytocin. Adverse effects such as ST segment depression, hypotension and tachycardia are well recognized, and have been implicated as a contributory cause of maternal death. Also, studies have demonstrated that prolonged use of oxytocin during induction of labor or augmentation can decrease the effectiveness of this measure. When AMTSL measures fail to control bleeding, therapeutic options include administration of additional uterotonics, uterine balloon tamponade, invasive uterine artery embolization, uterine compression sutures, and hysterectomy are employed. Recently, a multi-center randomized control trial using tranexamic acid failed to demonstrate significance in preventing postpartum hemorrhage in 11,000 patients. A novel method to treat PPH utilizing vacuum induced uterine tamponade has emerged as an effective therapy. We have developed a novel system that is specifically designed to tackle the numerous challenges of limiting blood loss, improving visualization, restoring and maintaining uterine tone and quantifying blood loss in cesarean sections. The aim of this Phase 1 is to finalize design parameters, materials validation, and functional performance testing. A successful Phase 1 will lead to the execution of an early feasibility trial.