Abstract: In recent years, premature delivery has an ascending trend in whatever developed countries or poorer areas. Premature infants is 45.9%—75% of neonates mortality, while 8%—25% survived infants have nerve and intelligence sequelae. The etiology of preterm labor and deliver is still not clear. Internal inflammation reaction may be its leading pathogeny. Manifold pathogen cause infection in uterine cavity, promote matrix metalloproteinases express rapidly in fibroblasts. MMPs decompose the extracellular matrix and regulate glycosamine, thus stimulates amnion, decidua and chorion to produce prostaglandin（PG）. PG can result in the preterm premature rupture of the membranes, the cervical ripening and dilation, uterine contraction and placenta abruption. At the end, premature delivery is unavoidable.

Key words: Matrix metalloproteinases, Premature birth, Fetal membranes, premature rupture, Cervical ripening, Chorioamnionitis