The role of fibrinolytic system in the maintenance of Pregnancy

Abstract

Various proteolytic mechanisms are known to be involved in the fertilization process. For example, it has been shown that seminal plasma contains a high fibrinolytic activity due to an activator of plasminogen, and the penetration of the spermatozoa through the cervical mucus and the zona pellucida of the ovum is influenced by proteolytic activity and controlled by protease inhibitors. On the other hand, plasminogen activator has long been known to be present in the ovary, thereby making available for ovulatory process. Furthermore, the fertilized ovum can be transported through high fibrinolytic activity of the fallopian tube, and for the implantation of the blastocyst, trophoblast with fibrinolytic activity is accepted by decidua where possesses an inhibitory effect of fibrinolytic activity. Thereafter, the low fibrinolytic activity remains with the chorionic villi. In the amniotic fluid, FDP levels increase gradually as pregnancy advances, whereas fibrinolytic inhibitors keep count of low concentrations.It is indicated that fibrinolysis and their inhibitors may play a significant role in the initiation and maintenance of pregnancy.