title: A comparison between the efficacy and side-effects of oral contraception using closely related combined and sequential preparations.
mesh_terms: D000293:Adolescent; D000328:Adult; D000568:Amenorrhea / Q000139:chemically induced; D002986:Clinical Trials as Topic; D003276:Contraceptives, Oral / Q000009:adverse effects*; D004412:Dysmenorrhea / Q000139:chemically induced; D005260:Female; D006261:Headache; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008535:Megestrol / Q000009:adverse effects; D008598:Menstruation; D008656:Mestranol / Q000009:adverse effects; D008881:Migraine Disorders / Q000139:chemically induced; D009325:Nausea / Q000139:chemically induced; D009765:Obesity / Q000139:chemically induced
chemical_list: D003276:Contraceptives, Oral; D008656:Mestranol; D008535:Megestrol