Collateral round ligament arterial supply of placenta accreta spectrum and considerations for prophylactic balloon occlusion catheter placement.

Internal iliac artery (IIA) balloon occlusion catheters have been commonly inserted to decrease the risk of post-partum hemorrhage in placenta accreta spectrum disorders, however, there has been mixed success in clinical trials. Placement of an infra-renal aortic balloon has shown more consistent efficacy in recent studies. A possible reason for this is collateral arterial supply to the placenta from external iliac artery branches. Retrospective chart review was conducted of angiography images during prophylactic IIA balloon occlusion catheter insertion over a 7-year period. 62 individual cases were identified. Digital subtraction angiography was performed in 32 (52%) cases, and 20 (62%) showed collateral blood supply from branches of the external iliac arteries, namely the round ligament artery. In conclusion, a high proportion of placenta accreta spectrum cases have arterial blood supply from branches of the external iliac artery, which may explain the discrepancy in efficacy seen between IIA and infrarenal aortic sites of balloon occlusion catheter placement.