In this paper, we applied a new theoretical model of uterine contraction to a large panel of human pregnant and non-pregnant myometrial strips, treated or not by Corticotrophin Releasing Hormone (CRH). This model is based upon a fine analysis of the contraction curves. This analysis yielded four mathematical parameters (Beta, Theta, Tau1 and Tau2) related to excitability, duration of plateau phase and time constants for relaxation describing respectively the different portions of the contraction cycle. This leads to specific differences in spontaneous contractile activity between pregnant and non-pregnant states. The relaxing effect of CRH in the pregnant state is presumably correlated with the origin of the strips (the lower uterine segment). Besides our observation of a specific receptor-dependent relaxing effects of CRH, in both pregnant and non-pregnant myometrium, we could identify highly significant effects at given CRH concentration for Beta in non-pregnant myometrium, and for Theta, Tau1 and Tau2 in pregnant myometrium. In addition, highly significant differences were found between pregnant and non-pregnant myometrium. Also we discovered a strong correlation between Theta and Tau1, specifically in the pregnant state. While the biochemical signification of these results remains to be elucidated, they contribute to emphasize the complex network of CRH action at the myometrial level. Furthermore, our approach could pave the way towards a better analysis of the efficacy of the uterine contractile behaviour.