Norethindrone-3-ethyldienolether;3-ETHOXY-19-NORPREGNA-3,5-DIEN-20-YN-17BETA-OL;NORETHINDRONE-3-ETHYLENOLETHER;Norethindrone 3-Ethyl Ether;Norethindrone Impurity 6(Norethindrone EP Impurity F);Norethindrone Impurity 3;3-ethoxy-17α-ethynyl-19-desmethylpregna-3,5-diene-17β-ol;Norethindrone EP Impurity F