title: A new approach to estrogen-free contraception based on progesterone receptor blockage by mid-cycle administration of ethyl norgestrienone (R 2323).
mesh_terms: D000328:Adult; D004341:Drug Evaluation; D005260:Female; D005298:Fertility / Q000187:drug effects*; D006067:Gonanes / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D006801:Humans; D006914:Hydroxysteroids / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D007664:Ketosteroids / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D008598:Menstruation / Q000187:drug effects; D011247:Pregnancy; D011374:Progesterone / Q000037:antagonists & inhibitors*; D045167:Progesterone Congeners / Q000494:pharmacology*; D011956:Receptors, Cell Surface; D014839:Vomiting / Q000139:chemically induced
chemical_list: D006067:Gonanes; D006914:Hydroxysteroids; D007664:Ketosteroids; D045167:Progesterone Congeners; D011956:Receptors, Cell Surface; D011374:Progesterone