Abnormal vascular architecture at the placental-maternal interface in placenta increta

OBJECTIVE: The objective of the study was to characterize the vascular architecture at the placental-maternal interface in pregnancies complicated by placenta increta and normal pregnancies. STUDY DESIGN: Vessel numbers and cross-section area density and spatial and area distributions in 13 placenta-increta placental beds were compared with 9 normal placental beds using computer-assisted image analysis of whole-slide CD31 immunolabeled sections. RESULTS: The total areas occupied by vessels in normal and placenta-increta placental beds were comparable, but vessels were significantly sparser and larger in the latter. Moreover, placenta-increta-vessel distributions (area and distance from the placental-myometrial junction) were more heterogeneous. CONCLUSION: Size and spatial organization of the placenta-increta vascular architecture at the placental-maternal interface differed from normal and might partially explain the severe hemorrhage observed during placenta-increta deliveries.