(8R,9S,10R,13S,14S,17R)-17-ethynyl-17-hydroxy-13-methyl-6,7,8,9,10,11,12,13,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-3(2H)-one; (17?)-17-Hydroxy-19-norpregn-4-en-20-yn-3-one; 19-Nor-17?? -ethynyl-4-androsten-17?-ol-3-one; 17?-Ethynyl-19-nortestosterone; 19-Norethisterone; Levonorgestrel Impurity U (EP)
