During pregnancy, although the uterus expands day by day, the contraction of uterine smooth muscle is always weak and basically in a calm state, so it will not cause discomfort to pregnant women. In the days leading up to delivery, uterine contractions gradually intensify. Mechanisms of Parturition Animal studies have accumulated evidence for the initial mechanisms of parturition, suggesting that the presence of the fetus is a key factor in initiating parturition; however, whether this hypothesis holds true for humans remains to be studied further. Maternal aspect,