Labor force includes uterine contraction force, abdominal wall muscle and diaphragm contraction force and levator ani muscle contraction force, among which uterine contraction force is the main one. During the delivery process, the rhythm, symmetry and polarity of uterine contraction are abnormal or the intensity and frequency are changed, which is called abnormal uterine contraction force. Clinically, obstructive dystocia is mostly caused by abnormal birth canal or fetal factors, which increases the resistance of the fetus through the birth canal, leading to secondary abnormal labor force. Abnormal uterine contraction force is clinically divided into two categories: uterine atony and excessive uterine contraction, each of which is further divided into coordinated uterine contraction and uncoordinated uterine contraction. Uterine atony refers to the polarity, symmetry and rhythm of uterine contraction are normal, but the uterine contraction is weak and powerless, the duration is short, the interval time is long or irregular. The fetal presenting part is unable to press on the lower uterine segment and the cervical os, that is, it is not enough to make the cervical os expand at a normal rate, resulting in prolonged or stagnant labor, and leading to a series of complications for mother and child. The disease has a higher incidence rate in women with local uterine factors such as malposition of the fetus, cephalopelvic disproportion, multiple pregnancies, twins, and polyhydramnios. It is also seen in those who are under mental stress. If the pregnancy and labor process can be handled promptly and correctly, the occurrence of uterine atony can be reduced.