A series of peri-substituted [4.3.0] bicyclic non-aromatic heterocycles have been identified as potent and selective hEP(3) receptor antagonists. These molecules adopt a hair-pin conformation that overlaps with the endogenous ligand PGE(2) and fits into an internally generated EP(3) pharmacophore model. Optimized compounds show good metabolic stability and improved solubility over their corresponding bicyclic aromatic analogs.