Synonyms: 19-Nor-17a-pregna-1,3,5(10)-trien-20-yn-17-ol,3-(cyclopentyloxy)- (6CI,7CI,8CI);17-Ethynylestradiol cyclopentyl ether;17a-Ethynylestradiol 3-cyclopentylether;3-(Cyclopentyloxy)-19-nor-17a-pregna-1,3,5(10)-trien-20-yn-17-ol;3-Cyclopentyloxy-17a-ethynyl-1,3,5(10)-estratrien-17-ol;3-Cyclopentyloxy-17a-ethynylestra-1,3,5(10)-trien-17b-ol;EECPE;Eston;Estrovis;Estrovis 4000;Estrovister;Ethynylestradiol-3-cyclopentyl ether;Plestrovis;Qui-Lea;W 3566;