Circulating progesterone (P4) levels decline before the onset of parturition in most animals, but not in humans. This has led to the suggestion that there is functional withdrawal of P4 action at the myometrial level prior to labor onset. Mifepristone is widely used to induce human labour In this study, we aimed to establish and validate a model of human myometrial explants for the study of P4 action. Myometrial biopsies obtained at Caesearean section at term were dissected into explants after a portion was immediately snap-frozen (t=0). Transcriptomic comparison of paired explants and primary myometrial cells as well as the hTert immortalized myometrial cell line demonstrated that explants more closely resemble t=0. Biopsies obtained from non-laboring women at elective Caesarean section at term were divided into 3: (i) dissected and immediately snap-frozen (t=0), (ii) dissected into 3x3x3mm3myometrial explants and (iii) processed for primary cell culture. Explants, primary cells at passage 4 (the typical passage our group uses for experiments) and hTERT cells were cultured for a period of 30 hours without treatment. Total RNA was extracted and microarray analysis performed. 6 replicates were used for this study.