While some women are struggling to make a choice between the ordeal of natural labor and the trauma of cesarean section, others say that the pain is not so intolerable, even in their first delivery, they have no recourse. < / P > < p > the five senses of the human body: vision, hearing, smell, touch and taste, can help us collect information from the outside world and enjoy life healthily and happily. < / P > < p > pain is usually caused by tissue damage. But sometimes, the injury does not really happen, only a kind of expectation of danger, but also can produce pain, that is, the pain caused by the so-called “psychological effect”. When it appears, no matter what we are doing right now, we can’t help but stop and care about its existence. < / P > < p > like other senses, pain is also the response of the nervous system to the original signal. When an injury or excessive stimulation occurs, a group of nerve cells called “nociceptors” in the tissue of the body are awakened. They receive injury signals and transmit them to the spinal cord. The spinal cord nerve is called the “signal highway”, and the signal is sent to the brain at high speed. Then, neurons and glial cells in the brain immediately process these signals, producing a sense of “pain.”. This unpleasant feeling activates an alarm network in the brain, and according to the source of the signal, the brain gives instructions to the corresponding “motor nerves” so that you can make actions to escape the source of the injury. At the same time, the brain also produces chemicals (such as endorphins) that help relieve pain. < / P > < p > when we describe pain, we need to distinguish between types and priorities. For example, if you go to see a doctor with a stomachache, he may ask: how many days did it last? Is it stabbing, muggy or burning? In addition, pain intensity often indicates the severity of the problem. < / P > < p > pain is very subjective, and everyone’s tolerance to pain (threshold) is also different. How to describe this? Doctors use tools to quantify the pain. For example, this scale: < / P > < p > take this standard as an example. Line level pain refers to severe injuries that are so severe that people can suddenly faint. For example, if the limbs are crushed in a car accident, few people will suffer from linear pain (such as pain caused by some cancers). It will make you feel desperate, need painkillers or desire surgery, and ignore the side effects or risks. The pain level of < / P > < p > 8 is close to the edge of people’s tolerance. At this time, it is difficult for people to calm down and only endure for a short time. As time goes on, personality changes will be caused. Labor pain of human beings belongs to this level. The labor pain mainly comes from the severe contraction of the uterus and the pressure on the cervix. This pressure can be felt in the pelvis and even the whole trunk, accompanied by compression and traction of the intestine, bladder and perineum. The uterus is a muscular organ. As long as 280 days of pregnancy, in order to adapt to the growth of the fetus, the uterus has been good temper expansion, acting as a container. As soon as the fetus is mature and delivered, under the instruction of oxytocin, the muscles of the uterus begin to contract rhythmically, and the strength is gradually strengthened, which will squeeze the baby into the birth canal a little bit. The mechanism of pain perception is common to human beings, but the sensitivity and endurance of pain can be significantly different. Therefore, some women can not tolerate the pain of vaginal delivery, and choose to have anesthesia cesarean section. However, in the long run, the recovery of the body after natural birth is generally faster, and the skin, abdominal muscle and uterine muscle layer need to be cut layer by layer during cesarean section, and the postoperative wound pain needs longer time to recover. Therefore, the clinical has been looking for ways to help women relieve labor pain. < / P > < p > in fact, some women don’t seem to have a strong sense of pain in childbirth. As we all know, adequate daily exercise and previous childbirth history are all factors to reduce pain. But recently, < / P > < p > has said that pain is ultimately caused by the signal transduction of the nervous system, and this signal is essentially the movement of charged ions caused by the opening / closing of ion channels on the surface of nerve cells, thus generating electric current. The ion channel is like a “door” of signals. Whether the door is easily opened or not determines the sensitivity threshold of nerve cells to the signal, that is, how much pain can be tolerated. < p > < p > the researchers collected the DNA of 158 women who were not sensitive to pain at the time of first delivery. After genetic analysis, they found that the homologous gene encoding kcng4 protein generally carried a single base mutation. The kcng4 protein encoded by the mutated gene will be < / P > < p >, which will reduce the possibility of pain signal reaching the brain and reduce the pain feeling produced by the brain. In other words, people become less sensitive to pain. This phenomenon has been verified in animal experiments. < / P > < p > pain can be concentration, which is conducive to childbirth. But more than the degree of pain tolerance will bring negative emotional, neuroendocrine effects, harm to the body. < / P > < p > some pregnant women who are sensitive to pain will ask for help. These drugs are injected into the epidural space around the spinal cord, temporarily blocking the transmission of injury signals from the spinal cord to the brain. But at the same time, it also interferes with the transmission of other senses, often resulting in prolonged labor, postpartum back pain and other side effects. < / P > < p > now there are some new delivery methods, such as “water delivery”, which claims to reduce the physical burden and pain of pregnant women. However, the cases of neonatal hypoxia and perineal laceration that can not be handled in time are not rare. In addition, the cost is relatively high, and the requirements for facilities are high. At present, the evidence-based medicine is not enough, so it can only be considered as an attempt. < / P > < p > first of all, single base variation of a single gene is better studied than complex multi gene variation and structural variation. Secondly, the protein encoded by the mutated gene can significantly reduce the pain perception threshold of the uterus, and other functions of the women with the mutation are normal, indicating that the effect of this mutation is not pathological. The variant protein < / P > < p > can make the pain of vaginal delivery more bearable, the pregnant women are awake and can concentrate on completing the delivery; at the same time, it also avoids the additional injury caused by cesarean section or anesthesia. Therefore, if we can develop new drugs based on this, it is expected to bring gospel to the majority of women. Before that, however, more work remains to be done. Kcng4 protein is also distributed in other body tissues (such as stomach). In addition to the ion signal channels on the nociceptive cells, there are many other levels involved in the common regulation. Does kcng4 variant protein affect other organs? Are there any genetic variations that have similar effects? < / P > < p > with the progress of gene sequencing and other research technologies, we may have more key findings, develop an effective and universal delivery pain improvement program, so that women can experience the joy of new life more smoothly and safely.