FIBRINOLYTIC PARAMETERS IN WOMEN UNDERGOING OVULATION INDUCTION

OBJECTIVE: The purpose of this study was to evaluate the effect of ele vated levels of circulating estradiol on the clotting and fibrinolytic system in patients undergoing controlled ovarian hyperstimulation. ST UDY DESIGN: Fifty-two patients undergoing controlled ovarian hyperstim ulation with human menopausal gonadotropins or urofollotropin were ask ed to participate. Blood for hemostasis parameters was obtained on the days that patients returned for estradiol sampling. Sample days were identified as cycle days 1 to 5 (baseline), 6 to 9, and 10 to 14. Each factor was analyzed by repeated-measures analysis of variance and cor relation analysis. RESULTS: A significant decline was observed for tis sue plasminogen activator antigen and plasminogen activator inhibitor type 1 activity from baseline to cycle days 10 to 14. As serum estradi ol levels increased throughout each phase (maximum mean estradiol 739. 8 pg/ml), a significant linear decrease was observed for both tissue p lasminogen activator antigen and plasminogen activator inhibitor type 1 activity, whereas thrombin-antithrombin III complexes did not change significantly. A significant positive correlation was also observed f or plasminogen activator inhibitor activity and tissue plasminogen act ivator antigen level over all cycle days examined. CONCLUSION: Down-re gulation of the fibrinolytic system was observed as estradiol levels i ncreased. However, thrombin formation did not change, thus suggesting that elevated circulating estradiol alone does not predispose to a thr omboembolic event.