[Platelet aggregation during various phases of the menstrual cycle and after therapy with ovulation inhibitors].

Collagen-induced platelet aggregation was studied under well defined experimental conditions in female volunteers on the 6th and 20th days of the menstrual cycle. In addition, another group on long-term contraceptives was investigated. The two parameters studied were the maximum amount and velocity of aggregation. In these three groups no significant changes were found in the parameters studied, and influences of the menstrual cycle and contraceptives on platelet aggregation are therefore unlikely.