This study will be investigated what mechanism of action Dienogest has. The growth of the follicles, the endometrium, the hormones in the blood and the mucus that is produced by the cervix that will be looked upon. Four different dosages of Dienogest (0.5 mg, 1 mg, 2 mg and 3 mg) will be investigated in healthy young women over two cycles, or up to a maximum of 72 days.