The main effect is to excite the smooth muscle of the uterus, promote the maturation of the cervix, enhance the contraction force and contraction frequency of the uterus, so it is widely used clinically in late pregnancy delivery. The indications for induction of labor are 1. premature pregnancy 2. premature rupture of membranes 3. certain pregnancy complications or comorbidities that require termination of pregnancy, such as pre-eclampsia, gestational diabetes mellitus, maternal and child blood type incompatibility, etc. 4, stillbirth 2 contraindications to induction of labor 1, pelvic stenosis or cephalopelvic disproportion 2, abnormal fetal position such as breech and transverse position 3, fetal distress 4, scarred uterus or uterine malformation, such as post-cesarean section, bicornuate uterine pregnancy, uterine fibroid excision. 5, excessive distension of the uterus, such as excessive amniotic fluid, twin pregnancies. 6, pregnancy combined with serious cardiovascular abnormalities, such as hypertension, heart disease. The dose and method of use in vivo is pulsatile, with a half-life of 1~6 minutes. It is rapidly destroyed by trypsin when taken orally and can be absorbed by any non-intestinal route. /If there is still no contraction, the concentration can be increased to 5U in 5% glucose liquid, and the effective contraction can be adjusted as follows: 3 contractions in 10 minutes, each lasting more than 30 seconds, accompanied by dilatation of the uterine opening. Another method of administration commonly used in clinical practice: 1. 0U contraction in 5% glucose liquid, starting with 8 drops per minute (1mU/min), and adjusting the number of drops to gradually increase the concentration according to the response of uterine contractions to: 2. 5U contraction in 5% glucose liquid, and 5U contraction in 5% glucose liquid. The method of increasing the concentration: calculated by the number of milliliters remaining in 5% glucose liquid, generally 100 ml of glucose with 0, 5 U of contraction to become 1% contraction concentration, first reduce the number of drops by half, then adjust according to the contraction situation, increase the concentration to 20 mU per minute still no effective contraction. In principle, the number of drops and concentration should not be increased anymore, because high concentration or high titration rate of contraction may cause intrauterine distress, amniotic fluid embolism or even uterine rupture. 2.Pulse drug delivery method is in accordance with the law of secretion of contraction in the body, but requires infusion pump. Therefore, it cannot be widely promoted. Low dose: start with a dose of 0.5~2mU/min, increase the concentration from 1~6mU/min with an interval of 15~40 minutes, and stop the drug when contractions are too strong. When reapplying, adjust the dose starting from 3mU/min. The contraction must be combined with the receptors in the body to work, and the half-life is short, there is no standard measurement, the safe dose of dangerous measurement, so we advocate small measurement, low concentration administration, only according to each maternal uterine contraction response to adjust. 1, because before delivery must be detailed medical history, physical examination, vaginal examination, understanding the condition of the birth canal, cervical scoring, to exclude contraindications to vaginal trial of labor. 2, the process of induction of labor must be attended to, not 15 minutes to record blood pressure, pulse, and contractions, fetal heart condition. If the fetal heartbeat is too slow, too fast or tonic uterine contractions, the person immediately slow down the drip rate or even stop, give oxygen, left-sided position, such as still tonic uterine contractions, the person must be intravenous magnesium sulfate drip to inhibit contractions. 3, only small doses of intravenous drip, other routes of administration are strictly prohibited: such as nasal drip, acupuncture point injection, intramuscular injection, etc. 4, the induction of labor on the way not to enter too much glucose fluid, not more than 1000ml in 24 hours to prevent water intoxication. 5, the cervix is not mature, induction of labor can not be successful Bishop cervical score 0 ~ 3, not easy to succeed, 4 ~ 6 success rate of 50% 7 ~ 8 success rate of 80%, more than 9 points can be successful. 6, the pregnant woman’s body contractin receptor status The body contractin receptor concentration in late pregnancy is significantly lower than that in full-term pregnancy, so the success rate of induction of labor is also lower than that of full-term pregnancy. Midterm pregnancy is replaced by other methods of inducing labor because of the low level of uterine contractin receptors, but high concentrations and large doses must be used to initiate contractions with contractin. 7. If the induction of labor is unsuccessful for 2-3 days, the possibility of vaginal delivery can be re-evaluated by another vaginal examination. If the cervix is more mature than before the induction of labor oh, you can manually break the membrane, combined with contractions spot induction of labor, to improve the success rate, while still early detection of cloudy amniotic fluid, so as to take appropriate measures. Side effects 1, contraction abnormalities contractions are too frequent (greater than 6 times / 10 minutes), too strong (a single contraction lasts more than 2 minutes), hyperstimulation syndrome (contractions are too frequent with abnormal fetal heart), can lead to emergency delivery, intrauterine distress, uterine rupture, amniotic fluid embolism, etc.. Slow down the drip rate of contraction, if necessary, stop the drug, or even give intravenous magnesium sulfate drip to inhibit contractions. 2, individual sensitivity and clearance rate of the contraction of the uterus varies greatly, it is difficult to master. In the course of the drip of contraction should emphasize dedicated supervision. 3, nausea, vomiting, occasionally allergic reaction to contractions, often manifested as chest tightness, shortness of breath, chills and even shock, need to use anti-allergic drugs for symptomatic treatment. 4, there is an anti-diuretic effect, excessive use, water intoxication may lead to convulsions or coma. 5.Condensin can increase the incidence of neonatal jaundice, associated with hyponatremia.