Synonyms: 19-Nor-17a-pregn-4-en-20-yn-3-one,10,17-dihydroxy- (6CI,7CI,8CI); 10b,17-Dihydroxy-19-nor-17a-pregn-4-en-20-yn-3-one; 10b,17b-Dihydroxy-17a-ethynylestr-4-en-3-one; 10b-Hydroxy-19-norethisterone; 10b-Hydroxynorethindrone; 10b-Hydroxynorethisterone; 17a-Ethinyl-10b,17b-dihydroxyestr-4-en-3-one; 17a-Ethynyl-10b,17b-dihydroxy-4-estren-3-one; NSC 63012