The purpose of this study is to evaluate whether a medical device called the Abdominal Aortic and Junctional Tourniquet - Stabilized (AAJT-S) can safely and effectively temporarily stop severe bleeding after childbirth (known as postpartum hemorrhage) when standard treatments fail. The main question the study aims to answer is: Can the AAJT-S device temporarily control life-threatening postpartum bleeding long enough to allow doctors to prepare for surgery and other definitive treatment?

This prospective, open-label, non-randomized, proof-of-concept study will assess the feasibility, safety, and preliminary clinical effectiveness of the Abdominal Aortic and Junctional Tourniquet - Stabilized (AAJT-S) device as a temporizing measure for severe postpartum hemorrhage (PPH) due to uterine atony that is unresponsive to standard first-line therapies. The study will be conducted in a tertiary referral center in Zaporizhzhia, Ukraine, located in a conflict-affected region with limited access to timely surgical intervention and blood products.

Eligible participants will be adult postpartum patients (≥18 years) who develop primary PPH with blood loss exceeding 1,000 mL and who fail to respond to pharmacologic uterotonics and balloon tamponade. Patients with hemorrhage due to trauma, coagulopathy, or retained placental tissue will be excluded.

Once standard management protocols are exhausted and eligibility is confirmed, the AAJT-S device will be deployed over the upper abdomen and inflated to 250 mmHg to achieve temporary occlusion of the abdominal aorta and inferior vena cava. The device is intended to reduce pelvic blood flow and thereby control hemorrhage during the critical window required to mobilize a surgical team, arrange blood transfusion, and secure anesthesia.

The device will remain in place for a maximum of 60 minutes, consistent with published safety guidelines. Clinical endpoints will include time to bleeding control, hemodynamic stabilization, need for additional surgical intervention, and total blood loss. Safety endpoints will include thrombotic events, ischemic injury, infections, and any other adverse events related to device use.

Data will be collected prospectively, including demographic characteristics, obstetric history, timing and duration of interventions, and perioperative outcomes. Descriptive statistics will be used to summarize findings, with no formal hypothesis testing due to the pilot nature of the study.

All participants will receive routine inpatient follow-up, and longer-term outcomes will be assessed via scheduled in-person visits and structured telephone interviews at 6 and 12 months postpartum to evaluate for delayed complications and maternal recovery. The study is designed to generate preliminary data for further exploration of the AAJT-S device as a potential emergency tool for PPH management in resource-limited and crisis settings.

Inclusion Criteria:

• Age ≥18 years
• Clinical diagnosis of postpartum hemorrhage (PPH) refractory to uterotonics and intrauterine balloon tamponade
• Estimated blood loss greater than 1,000 mL
• Oral informed consent provided prior to device application

Exclusion Criteria:

• Patients with postpartum bleeding as a result of trauma, retained placenta or coagulopathy were excluded

Self-identified females who are biologically capable of pregnancy and childbirth are eligible to participate. The study includes individuals assigned female at birth with a functioning uterus who have delivered vaginally and experienced postpartum hemorrhage. Participation is limited to those with physiologic ability to undergo the obstetric processes being studied.

Individual participant data (IPD) will not be shared due to the small sample size and the sensitive nature of the clinical context, including emergency obstetric care in a war-affected setting. Additional ethical and regulatory considerations related to patient privacy and consent limit the possibility of external data sharing.