From the perspective of mechanism of action, the role of contraction is to promote uterine contraction. However, from the perspective of clinical application, the role of contractions is mainly in the following aspects: 1. Prevention or treatment of postpartum hemorrhage, such as the use of contractions after a medical abortion, can prevent bleeding, and at the same time can promote the discharge of residues in the uterine cavity. After miscarriage, induction of labor or normal delivery of a large month child, you can use contractions to promote uterine contraction and prevent hemorrhage. When patients experience hemorrhage due to weak contractions after induction of labor, they can be treated with contractions; 2. When women are in the middle or late stages of pregnancy and cannot deliver normally because of fetal developmental abnormalities or other reasons, they can use contractions to induce labor; 3. Women who have reached their due date can also use contractions to induce labor if they cannot initiate contractions normally, and they should closely observe the fetus in the uterine cavity, as well as the condition of the mother’s body. To avoid fetal distress, placenta abruptio or amniotic fluid embolism, etc.