Changes in coagulation factors in postmenopausal women on ethinyl oestradiol.

Coagulation factors II, VII, X, VII + X complex and anti-thrombin III were measured in 10 postmenopausal women before, during and after a four-month course of 20 microgram daily of ethinyl oestradiol, taken three weeks in four. Factors VII, X and VII + X complex rose significantly during treatment but only factor X levels were significantly elevated at the end of the four-month treatment period. There was no change in factor II or anti-thrombin III levels. These effects on coagulation factors during ethinyl oestradiol therapy are, in general, similar to those found during treatment with conjugated equine oestrogens and oestradiol valerate in a previous study from the same laboratory. It seems likely that equipotent doses of ethinyl oestradiol and 'natural' oestrogens have similar effects on these coagulation factors.