Usually, contractions are mainly used to induce labor or labor, mainly by intravenous infusion, starting with the lowest effective dose and supervised by someone, and usually contractions start within 3-5 minutes after the infusion. If the woman’s cervix is in good condition, it is more likely to work; if the cervix is not in good condition and she is not full term, it may take longer to work and other measures may be needed to help induce labor. The effect of contractions can last for 20-30 minutes, but there are some individual differences. The main effect of the injection is to stimulate the smooth muscles of the uterus, enhancing the force and frequency of contractions. In the second trimester, especially during labor, the uterus is more sensitive to the contraction injection, which facilitates the delivery of the fetus. In addition, the contraction injection has the effect of promoting breast milk production and lowering blood pressure. In case of postpartum hemorrhage or post-abortion hemorrhage, the uterine contraction injection can be administered immediately, which can have a rapid effect, causing tonic contraction of the smooth muscle of the uterus and compressing the blood vessels in the muscular layer to stop bleeding. In addition, the dosage of the contraction injection varies in different cases, which has a certain impact on the onset of action, and doctors will choose according to different situations to achieve the best results. If the woman has a scarred uterus, cephalopelvic disproportion, etc., she should also avoid using it before delivery in accordance with medical advice to avoid causing uterine rupture and danger.