Summary
In this randomised, placebo-controlled 12-week study, sixty healthy postmenopausal
women received either placebo (N = 16) or daily 2 mg micronised oestradiol, either
unopposed (N = 16, E2 group) or combined with a progestagen for 14 days of each cycle (N = 28, E2+P group).
Results
As compared to placebo, plasma levels of AT III were reduced only in the E2 group (∼28%), plasma levels of protein C decreased only in the E2+P group (∼4%) and plasma levels of protein S decreased in both the E2 and E2+P group (∼21%). In both the E2 and E2+P groups, the plasma levels of factor VII (antigen and activity) showed a borderline
significant increase (∼10%), whereas no significant change was observed in active
factor VII. Plasma levels of tissue-type plasminogen activator (∼22%), urokinase plasminogen
activator (∼25%) and plasminogen activator inhibitor type-1 (∼43%) decreased in the
E2 and E2+P groups, whereas those of plasminogen increased (∼12%). Treatment was associated
with an increase in levels of prothrombin fragment 1+2 (∼31%), but levels of thrombin-antithrombin
III complexes, and of plasmin-α2-antiplasmin complexes and total fibrin(ogen) degradation products did not change
significantly.
Conclusion
Short-term E2 and E2+P treatment is associated with a shift in the procoagulant-anticoagulant balance
towards a procoagulant state. A substantial proportion of women do not have a net
increase in fibrinolytic activity. These data may be relevant in explaining the increased
risk of venous thromboembolism associated with ERT and HRT, and possibly also in explaining
the negative results of the Heart and Estrogen/progestin Replacement Study.
Key words
Hormone replacement therapy - coagulation - fibrinolysis - postmenopausal