The effect of specific hormones on fibrinolysis in pregnancy

OBJECTIVE: 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-17β, 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. STUDY DESIGN: Human umbilical vein endothelial cells were grown with physiologic third-trimester concentrations of the above hormones, and fibrinolytic parameters were measured. RESULTS: 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 β significantly increased tissue plasminogen activator antigen and progesterone significantly decreased tissue plasminogen activator antigen, but neither affected the overall fibrinolytic balance. CONCLUSION: 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-17β, progesterone, or prolactin. (Am J Obstet Gynecol 1996;175:168-72.)