The effect of specific hormones on fibrinolysis in pregnancy.

Abstract

Plasminogen activator inhibitor-1, the major serum protease inhibitor of fibrinolysis, increases steadily during pregnancy. The study objective was to examine four hormones, namely, estradiol-17 beta, progesterone, prolactin, and hydrocortisone to determine their individual contributions in the production of tissue plasminogen activator antigen, plasminogen activator inhibitor-1 antigen, and plasminogen activator inhibitor-1 activity. Human umbilical vein endothelial cells were grown with physiologic third-trimester concentrations of the above hormones, and fibrinolytic parameters were measured. Of the four hormones evaluated, only hydrocortisone significantly increased plasminogen activator inhibitor-1 antigen and activity at both concentrations tested (p < 0.001). Estradiol-17 beta significantly increased tissue plasminogen activator antigen and progesterone significantly decreased tissue plasminogen activator antigen, but neither affected the overall fibrinolytic balance. Hydrocortisone demonstrated antifibrinolytic properties at physiologic concentrations in pregnancy, suggesting that there may be a role for hydrocortisone in the prothrombotic tendency associated with pregnancy. The overall process of fibrinolysis was unaffected by estradiol-17 beta, progesterone, or prolactin.