Hemostatic changes induced by exercise during oral contraceptive use.

Exercise-induced changes in hemostatic measurements were studied in 25 women. Twelve of the subjects were not using oral contraceptives and the remainder were using Demulen (ethynodiol diacetate (1 mg) and ethinyl estradiol (0.05 mg)). Exercise on a treadmill induced similar changes in both groups, but during the use of Demulen the levels of fibrinogen and plasminogen were higher, antithrombin level was lower, and the recalcified clotting and dilute whole blood lysis times were shorter in group 2 than in the corresponding samples obtained from the nonpill users.