Importance of the type of the progestogen in oral contraceptives.
D003276:Contraceptives, Oral / Q000627:therapeutic use*; D004997:Ethinyl Estradiol / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008535:Megestrol / Q000627:therapeutic use; D008875:Middle Aged; D011372:Progestins / Q000627:therapeutic use*
D003276:Contraceptives, Oral; D011372:Progestins; D004997:Ethinyl Estradiol; D008535:Megestrol