Effect on blood coagulation and fibrinolysis in women using norethisterone or a combination of ethinyloestradiol and quingestianol.

Oral contraceptives of the combined type and contraceptives containing only progestagen were studied for their effect on blood coagulation and fibrinolysis. Several blood parameters were determined in 13 women before and during the 3rd month of use of either 0.3 mg norethisterone alone or 0.05 mg ethinyloestradiol combined with 0.5 mg quingestianol. Blood samples were obtained on days 2--4, 9--11, 16--18 and 23--25 of the menstrual cycle. Except on days 16--18, a significantly increased fibrinolytic activity and a significantly increased variation in plasminogen were observed in women using the combined type of contraceptives, but not in the women using contraceptives containing only norethisterone. The other variables studied were not significantly changed, which might be due to the doses and types of progestagens used in the present series.