Abstract: Premature rupture of the membranes (PROM) is a very common and rather difficult problem in obstetrics, and it is also a common cause of premature birth. There are many reasons for PROM and its pathogenesis is very complicated. This article reviews the histological characteristics of the fragment of the fetal membrane, including the foundings of the traditional pathology and the new optical research. Secondly, we introduce a new discovery that membranes have small cracks and is continuous remodeling. In addition, some membranes had the spontaneous healing, and its mechanism is mainly a physical closure based on cell migration. Last but not the least, we conclude some new theories, such as fetal membrane senescence and oxidative stress, and the traditional theories, such as cell apoptosis, and the imbalance of fetal membrane protease system, in order to provide theoretical ideas for further studies on PROM.

Key words: Fetal membranes, premature rupture, Placenta, Senescence, Heal, Pregnant women