Specific inflammatory microenvironments in the zones of the fetal membranes at term delivery

Objective: The purpose of this study was to examine the histologic and immunologic differences between fetal membrane zones after membrane rupture at term delivery. Study Design: Fetal membrane explants from postrupture zones (periplacental, middle, rupture) were obtained from women following spontaneous vaginal delivery at term (n = 5). Tissues for histology, protein extracts, and RNA were isolated. Results: The collagen distribution decreased and the leukocyte density increased from the periplacental zone to the rupture zone. T cells were mainly present in the rupture zone and granulocytes in the middle zone. CXCL10, CXCR1, ICAM-1, -2, PSEL, tumor necrosis factor alpha, and matrix metalloproteinase-9 levels were higher in the middle zone than in the rupture zone and periplacental zone (P <.021). Interleukin-1beta and CXCL8 levels were higher in the rupture zone than in the middle zone and periplacental zone (P =.018 and P <.0001). Conclusion: During labor specific immunologic microenvironments are created in the zones of the fetal membrane that may be involved in their rupture at the end of gestation.