Amniochorion membranes were collected from 25 pregnant women at preterm labor, in the presence or not of Preterm Premature Rupture of Membranes (PPROM) and 27 pregnant women at term in the presence at labor, in order to quantify the expression and to evaluate the immunoreactivity of human beta defensins (HBD)1, HBD2, HBD3 and HBD4 in amniochorion membranes from pregnancies complicated by spontaneous prematurity. The HBDs were evaluated by immunohistochemistry, real time quantitative PCR and ELISA. Statistical analyses were performed using Chi-squared and Mann Whitney tests. There was no significant difference in HBDs expression between study and