**5. Future directions**

REBOA is a novel, minimally-invasive method to control non-compressible hemorrhage. Much of the literature regarding techniques for placement and risks of use are derived male trauma patients. More research is needed to investigate the use of REBOA in a peripartum setting. Reports of prophylactic use of REBOA to minimize blood loss during high-risk obstetric operations, claim to reduce blood loss and improve rates of uterine salvage compared to other types of arterial occlusion techniques, such as hypogastric and uterine artery occlusion. Most of this evidence comes from retrospective case series out of Asia. Comparative data is needed to examine the risks and benefits of REBOA compared to other methods of hemorrhage control utilized in the West. Although case reports and case series have shown that REBOA can successfully provide temporary control of obstetric hemorrhage, up to three liters of blood loss has been reported in these cases despite aortic occlusion. Larger studies are needed to quantify the expected hemorrhage volume during aortic occlusion to help inform perioperative plans.

Furthermore, instructions on REBOA use and placement for the obstetric patient are extrapolated from the trauma literature. Whether external landmarks on the gravid abdomen can be used reliably for positioning of REBOA has yet to be determined. More research is needed to establish whether imaging is needed to verify balloon position prior to inflation, and to assess the associated risk of radiation exposure to the fetus. The optimal zone of REBOA inflation is not known for obstetric hemorrhage. More research should focus on defining collateral pathways for circulation to the gravid uterus, especially in the case of abnormal placentation. Additionally, the effect of proximal vs. distal occlusion on blood pressure support during various stages of hemorrhagic shock should be established to aid in defining the optimal level of occlusion for initial balloon inflation in prophylactic and reactive settings.

Finally, the risks of REBOA are also generated from its reactive placement in trauma patients experiencing hemorrhagic shock. Although it can be assumed that prophylactic use of REBOA during planned obstetric procedures will have decreased risk compared to trauma situations, more research is needed to investigate this use of REBOA. As the adoption of REBOA for obstetric hemorrhage becomes more prevalent, it is expected that increasing evidence will help delineate more definitive guidelines for this population.
