Labor analgesia refers to the use of drugs or psychotherapy to reduce maternal pain during childbirth. The mechanism and characteristics of labor pain: Labor pain mechanism: Labor pain is the most severe pain most women encounter in their lifetime. Physiologically speaking, labor pain comes from the uterine contractions and the damage to the uterus and birth canal tissues during the delivery of the fetus, which stimulates the nerve endings and generates electrical impulses along the lumbar and sacral nerves to the spinal cord and then to the nociceptive center of the brain, thus causing the woman to feel severe pain. The main characteristic of pain is that the pain is diffuse, and the mother cannot tell the location and nature of the pain; the second stage of labor is from the opening of the cervix to the delivery of the fetus, and the pain mainly comes from the stretching, dilation, involvement and tearing of the muscles, fascia and skin of the lower birth canal, and the pain is sharp and intense, and the pain area is clearly concentrated in the vagina, rectum and perineum. The pain is characterized by sharp and severe pain, and the pain area is clearly concentrated in the vagina, rectum and perineum. Common analgesic methods 1, epidural anesthesia Epidural anesthesia has become the most common method of labor analgesia, also known as walkable labor analgesia, including continuous epidural block anesthesia and maternal self-controlled epidural analgesia by the micropump method. In the maternal self-controlled epidural analgesia, attention should be paid to: (1) strengthening education, explaining the process of using this method to the mother before anesthesia to obtain her cooperation; (2) observing the condition of the mother and the fetus and giving analgesia at the right time; (3) paying close attention to the progress of labor and guiding the mother in labor. 2.Inhalation pain relief method Maternal inhalation of the main components of 50% NO (laughing gas) and 50% O2 (oxygen) gas, can reduce labor pain. This method can be used in the first and second stage of labor, and can be applied when the pain starts. Its advantages include the following: less toxicity, no irritation to the respiratory tract, no combination with hemoglobin, no adverse effects on heart rate, blood biochemistry, liver and kidney function, etc.; obvious pain effect, can eliminate the fear of the mother; the mother always stays awake, can actively cooperate with the completion of labor, which is conducive to shortening the labor process. Perineal nerve block Perineal nerve block is used to relieve perineal pain during the second stage of labor when the fetus is delivered, and it can also be used for lateral incision anesthesia. It is a simple method, fast acting, and has no effect on the fetus. 4.Self-hypnosis method Self-hypnosis is a new method in non-pharmacological painless delivery. Self-hypnosis is a kind of hypnosis, which is usually guided by medical personnel to make the patient reach an altered state of perception. In childbirth, the main purpose of this method is to control anxiety and pain by guiding the mother to a state of relaxation or concentration, so that she can control herself. 5.Painless childbirth instrument The painless childbirth instrument is developed according to the principle of acupuncture and moxibustion in China about the five points on the back of the ear and the ability to diagnose and treat the corresponding internal diseases on the auricle. The eardrum of the painless delivery device is applied to the auricular acupuncture points of both ears of the mother, and the continuous stimulation by electric pulses raises the pain threshold of the local skin and uterus and transmits information to the center, which activates the anti-cancer system in the body and releases 5-hydroxytryptamine and endogenous opioid area to produce analgesic effects. Its advantages are good analgesic effect, long duration of action, promotion of uterine contraction, shortening the labor process, simple operation, and no harm to both mother and child. The disadvantage is that the analgesia is not complete. 6.Water injection labor analgesia In China, there are more research reports on water injection labor analgesia. The method is to select a longitudinal midline at the spinous process of the 5th lumbar vertebra and open 2 cm to the left and right for the injection point, so that the two points are each 2 cm down, a total of 4 injection points, and inject 0.5 ml of sterile injection water into each of the 4 points to form a mound of about 1.5 cm in diameter. The advantages of water injection for labor analgesia include: high analgesic efficiency, shortened labor, no effect on postpartum hemorrhage and neonatal score, simple operation, less invasive, no need for special equipment, easy to master, and the sterile injection water used is non-pharmaceutical, which has no effect on both mother and baby in the near and long term.