Synonyms: Estra-5(10),9(11)-diene-3,17-dione,cyclic 3-(ethylene acetal) (7CI,8CI);Spiro[3H-cyclopenta[a]phenanthrene-3,2'-[1,3]dioxolane],estra-5(10),9(11)-diene-3,17-dione deriv.;3,3-(Ethylenedioxy)estra-5(10),9(11)-dien-17-one;Estra-5(10),9(11)-diene-3,17-dione,cyclic 3-(1,2-ethanediyl acetal);