A Comparison between Effects of Estradiol Valerate and Low Dose Ethinyl Estradiol on Haemostasis Parameters

Abstract

Ethinyl estradiol (EE) is still used to some extent as hormonal replacement therapy (HRT) in the climacteric period. As regards oral contraception, it is well known that the induced increase in cardiovascular disease is related to the estrogen component (invariably EE) in a dose-related fashion. Considerably lower doses of EE are needed in HRT compared to oral contraception. To delineate and compare effects of EE and estradiol valerate (E2V) in doses needed in HRT on haemostasis parameters, 24 postmenopausal women were engaged in a study with an open cross-over design. The doses compared (10 micrograms EE and 2 mg E2V daily) are the lowest which eliminate climacteric symptoms in a majority of women. Unlike E2V, EE caused increased levels of factor VII:Ag, factor VIII:C and beta-thromboglobulin, which may be changes towards hypercoagulability. Both estrogens decreased the AT III activity. Long-term administration (6 + 12 w) of the estrogens induced further changes in haemostatic parameters. 10 micrograms EE increased factor VII:Ag in contrast to 2 mg E2V. Furthermore both estrogens increased factor VIII:C and factor II-VII-X. A decrease in platelet count was induced by both EE and E2V. Oral contraception and adjuvant estrogen therapy in men with prostatic carcinoma are known to imply an increased cardiovascular risk. It is noteworthy that the pattern of changes in haemostatic parameters induced by as little as 10 micrograms of EE is the same as seen after the administration of combined oral contraceptives or the substantially higher doses of EE given as adjuvant therapy to men with prostatic carcinoma.