title: Chinical experience with levonorgestrel and ethinyl estradiol in Beijing.
mesh_terms: D000328:Adult; D002681:China; D003277:Contraceptives, Oral, Combined / Q000009:adverse effects; D004997:Ethinyl Estradiol / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D016912:Levonorgestrel; D008599:Menstruation Disturbances / Q000209:etiology; D009644:Norgestrel / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D003277:Contraceptives, Oral, Combined; D009644:Norgestrel; D004997:Ethinyl Estradiol; D016912:Levonorgestrel