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.