title: Oral contraception by norethynodrel. A 3 year field study.
mesh_terms: D035843:Biomedical Research; D003267:Contraception; D003270:Contraceptive Agents; D003276:Contraceptives, Oral; D005260:Female; D006801:Humans; D009641:Norethynodrel; D011374:Progesterone / Q000031:analogs & derivatives
chemical_list: D003270:Contraceptive Agents; D003276:Contraceptives, Oral; D011374:Progesterone; D009641:Norethynodrel
keywords: CONTRACEPTIVES, ORAL; PROGESTERONE/related compounds