Abstract: Objective： To investigate the expression and its clinical significance of human beta-defensin-3（hBD3） in premature rupture of fetal membranes of pregnant women. Methods：Randomly selected 45 cases who delivered in the department of obstetrics and gynecology of our hospital and diagnosed primiparous patients with preterm premature rupture of membranes as PPROM group，and selected 45 cases of normal pregnancy during the same period as control group. Detected the expression of hBD3 in fetal membranes by immunohistochemical，and determined serum TNF-α，hBD3 content by enzyme linked immunosorbent assay. Results：Premature rupture of the epithelial cells observed in the brown staining was positive expression. PPROM group beta defensin 3（+） expression in 33 cases，12 cases were negative; the control group beta defensin 3（+） expression in 13 cases，32 cases were negative，there was significant difference between two groups（P＜0.05）. Compared with the control group，serum TNF-α，hBD3 increased significantly at admission and delivery of premature rupture of membranes（P＜0.05），and PPROM group serum TNF-α，hBD3 delivery were higher than the admission（P＜0.05）. Conclusions：hBD3 may be involved in the natural immune responses against microorganism mediated by TNF-α.

Key words: Beta-defensins, Fetal membranes, premature rupture, Tumor necrosis factor-alpha, Pregnant women