Summary
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 μg 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 β-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 μg 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 μg 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.
Key words
Estrogens - Antithrombin III activity - Factor VII: Ag - Factor VIII: C - β-thromboglobulin
- Cardiovascular disease
