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Postmenopausal hormone replacement therapy increases coagulation activity and fibrinolysis
H J Teede1, B P McGrath, J J Smolich
1Cardiovascular Research Group and Centre for Heart and Chest Research, Department of Medicine, Monash University, Monash Medical Centre, Clayton, Victoria, Australia.
Arteriosclerosis, Thrombosis, and Vascular Biology
|May 16, 2000
Summary
Combined hormone replacement therapy (HRT) in postmenopausal women activates coagulation and fibrinolysis. This HRT may increase the risk of blood clots and cardiovascular events, despite potential cardioprotective effects.
Area of Science:
- Endocrinology
- Cardiovascular Medicine
- Hematology
Background:
- Hormone replacement therapy (HRT) is used by postmenopausal women.
- HRT may offer cardioprotective benefits.
- Concerns exist regarding HRT's potential thrombogenic effects.
Purpose of the Study:
- To investigate the impact of combined HRT on coagulation and fibrinolysis.
- To measure circulating markers of hemostasis in postmenopausal women undergoing HRT.
Main Methods:
- A double-blind, placebo-controlled trial was conducted.
- Forty-two healthy postmenopausal women (50-75 years) received 6 weeks of combined HRT (2 mg estradiol + 1 mg norethisterone) or placebo.
- Circulating markers of coagulation and fibrinolysis were measured at baseline and after 6 weeks.
Main Results:
- HRT significantly increased markers of coagulation, including prothrombin fragments 1+2 and soluble fibrin.
- HRT reduced plasma fibrinolytic inhibitory activity (plasminogen activator inhibitor-1).
- HRT increased fibrinolysis, indicated by elevated D-dimer levels, which correlated with increased fibrin generation.
Conclusions:
- Short-term oral combined HRT (estradiol and norethisterone) activates thrombin and fibrin generation.
- HRT enhances fibrinolysis, linked to increased fibrin generation but not reduced PAI-1.
- Coagulation activation during HRT may contribute to reported increases in venous thrombosis and cardiovascular events.