title: Clinical performance with contraceptive vaginal rings containing levonorgestrel.
mesh_terms: D000293:Adolescent; D000328:Adult; D002986:Clinical Trials as Topic; D003274:Contraceptive Devices, Female / Q000009:adverse effects; D005260:Female; D006801:Humans; D016912:Levonorgestrel; D008599:Menstruation Disturbances / Q000209:etiology; D009644:Norgestrel / Q000009:adverse effects; D010342:Patient Acceptance of Health Care; D010352:Patient Dropouts; D011247:Pregnancy
chemical_list: D009644:Norgestrel; D016912:Levonorgestrel