The opening time of the uterus after the use of oxytocin is individual and cannot be generalized, but should be determined by the condition of the cervix, the degree of sensitivity to oxytocin, the frequency of delivery, the number of weeks of pregnancy, the size of the fetus, and the position of the prelude, etc. 1) The uterus opens more quickly: Usually, if the degree of sensitivity to oxytocin is high, the second child is born, or the physical condition of the mother is good, and the prelude of the fetus is low, the size is small, and the position of the fetus is more positive, the uterus can be opened within 12 hours after the use of the injection. In the case of more positive, the uterine opening can be seen within 12 hours after the use of oxytocin; 2, the opening of the uterine mouth is slower: if the sensitivity to oxytocin is low, > 41 weeks there is no sign of labor, or suffering from hyperemesis gravidarum, gestational diabetes mellitus and other diseases, and then induce labor, labor induction of mothers, it may need to be continued to use the 1-3 days after the birth; 3, the uterine mouth does not open: some of the mothers of the insensitive to the oxytocin or the existence of the cephalo-pelvic disproportion, so in the use of the oxytocin, the uterine mouth is not opened. 3, the mouth of the uterus does not open: some women are not sensitive to oxytocin or there is cephalopelvic disproportion, so in the process of using oxytocin can not expand the mouth of the uterus, resulting in the failure of oxytocin, this kind of maternal need to carry out cesarean section to terminate pregnancy. Oxytocin can promote uterine contractions and dilatation of the uterine opening, so pregnant women using oxytocin need to closely observe the progress of labor and be ready for delivery at any time, and can also promote the progress of labor through appropriate exercise.