[Effect of hormonal contraceptives, different in composition, on the fibrin-stabilizing factor (factor XIII) (author's transl)].

Plasma activities of the fibrin-stabilising factor (Factor XIII) were tested in 60 women who were on hormonal contraceptives, different in composition (Non Ovlon and Gravistat). The activities in either group were reduced with significance, notwithstanding steroid levels. Unambiguous interpretation of that reduction proved impossible.