The effect of different regimens of oestrogens on the clotting and fibrinolytic system of the post-menopausal woman.

The effects of six different regimens of hormone replacement therapy on coagulation, fibrinolysis and platelet aggregation were sudied in 33 symptomatic, post-menopausal women. Studies were performed before and after 3 months of therapy in the six treatment groups, Premarin, Progynova, Harmogen, Serial 28, ethynodiol diacetate and a testosterone and oestradiol implant. No changes in any parameter were detected following administration of Premarin, Progynova or an implant of testosterone and oestradiol. Serial 28 produced a significant increase in plasminogen concentration and increased the extent of platelet aggregation in 0.5 micron adrenalin solution. Harmogen produced an increase in the extent of platelet aggregation in 1.0 micron adrenalin solution, but a decrease in the rate of platelet aggregation in 1.0 micron solution. Ethynodiol diacetate caused a significant decrease in the kaolin-cephalin clotting time but decreased the extent of platelet aggregation in 0.5 and 1.0 micron solutions of adrenalin. FDPs developed following therapy in 9 of the 33 patients. These were evenly distributed between the groups. No patients had any change in anti-Xa concentration, platelet count or platelet aggregation in thrombin.