A 12-month clinical investigation with a 24-day regimen containing 15 microg ethinylestradiol plus 60 microg gestodene with respect to hemostasis and cycle control.

The effects of a 24-day regimen containing 15 microg ethinyl estradiol (EE) plus 60 microg gestodene on cycle control and on hemostasis, were evaluated in 58 healthy women (age 19-47 years). All women received the pill for 12 months. Withdrawal bleeding at every cycle during the tablet-free interval was experienced by 84.5% of the women. The overall incidence of irregular bleedings was 19.3%. Hemostasis was evaluated in 20 women. No changes in plasma fibrinogen concentrations, nor in prothrombin fragment F1+2 were observed. A slight increase in thrombin-antithrombin III complexes was observed after 6 and 12 months of oral contraceptive use. Antithrombin III activity significantly increased after one-year of pill intake. The concentrations of tissue plasminogen activator and plasminogen activator inhibitor, both antigen and activity, did not change. These results show that very low doses of EE, such as 15 microg, do not impair hemostasis in healthy females. However, the reduction for the EE dose is responsible of some of the effects on cycle control.