If we are to develop new strategies for the treatment and management of preterm and dysfunctional term labour, it is imperative that we improve current understanding of the control of human uterine activity. Despite many studies of animal pregnancy, there is a paucity of knowledge relating to the complex control of human myometrium during pregnancy. It is hypothesized that human myometrium is relatively quiescent during the majority of pregnancy and that as term approaches there is cascade of molecular events that prepare the uterus for labour. This review will consider the cellular mechanisms involved in the regulation of human myometrial activity and the modulation of these by hormonal and mechanical signals. In particular, the contribution of calcium homeostatic pathways to the control of human myometrial contractility during gestation will be discussed. Experimental Physiology (2001) 86.2, 247-254.