Failures of contraception on the lower dose ethinyl estradiol sequential therapy: a clinical trial.
D000328:Adult; D002715:Chlormadinone Acetate / Q000008:administration & dosage; D003276:Contraceptives, Oral / Q000008:administration & dosage* / Q000009:adverse effects; D004997:Ethinyl Estradiol / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D011247:Pregnancy
D003276:Contraceptives, Oral; D002715:Chlormadinone Acetate; D004997:Ethinyl Estradiol