The contraction of a large muscular organ like the uterus has to have significant systemic repercussions particularly because a very large proportion of the cardiac output, supplying the IVS circulation, passes through it. Almost every bodily system or apparatus is affected by the contractions of the uterus, but only those directly involved in sustaining fetal life (cardiovascular system) and those related to the painful reactions produced by the contractions or interventions to control the pain (central nervous system) are reviewed here.