Guided by antiprogestational screening results, 4-substituted(4-OH, 4-Cl, 4-Br, and 4-OMe) 17 beta-hydroxy-7 alpha-methyl-4-estren-3-one and their 17-acetate were synthesized via 4 beta, 5 beta-epoxy-17 beta-hydroxy-7 alpha-methylestran-3-one from 17 beta-hydroxy-7 alpha-methyl-4-estren-3-one. Some of these compounds possess strong affinity to human decidual progesterone receptor, inhibit in vitro the growth of decidual cells, and prevent the implantation in rats at the dose of 1 mumol/kg.