Blood Coagulation/drug effects; Ethinyl Estradiol/administration & dosage; Ethnicity; Fibrinolysis/drug effects; Norgestrel/administration & dosage; Adult; Antithrombin III/metabolism; China; Female; Humans; alpha-2-Antiplasmin/metabolism

Asians; Biology; Blood Coagulation Effects; Contraception; Contraceptive Agents; Contraceptive Agents, Female; Contraceptive Methods--side effects; Cultural Background; Demographic Factors; Ethinyl Estradiol; Ethnic Groups; Examinations And Diagnoses; Family Planning; Fibrinolysis; Hematological Effects; Hemic System; Incidence; Laboratory Examinations And Diagnoses; Laboratory Procedures; Levonorgestrel; Oral Contraceptives--side effects; Physiology; Population; Population Characteristics; Prospective Studies; Reproductive Control Agents; Research Methodology; Studies; Thromboembolism; Whites