Untreated pain will also cause long term impact on newborns,Some scientists in foreign countries have done some research on rats, they found that if rats were exposed to pain for a long time, its nociception neural circuit's development will be harmed, and the pain threshold will be lowered. For newborns, untreated pain will cause hypalgesia when they are in puberty and hyperalgesia after adulthood. The experience of pain in infancy also affects the babies' later life after they grow up, it may cause emotional problems, minimal brain dysfunction, social intercourse defect and so on. So it is very important to find out useful interventions to decrease pain in newborns, considering the long term impact and side effect of medicine, it is seldom to use medical interventions to decrease pain. Non-pharmacological interventions become quite important. In foreign countries, there have been kinds of useful non-pharmacological interventions such as kangaroo care, breast-feeding, sucrose and non-nutritive sucking. While in China, there are massage, positioning, sucrose, music and kangaroo care that proved to be effective to decrease pain in newborns. The investigators find few reports about breastfeeding or non-nutritive sucking's effect of decreasing pain in term newborns. For breast-feeding, it includes the nursing mother who has consoling impact, hugging, attention transferring, taste, the breast milk contains tryptophane, which is the precursor of N-acetyl-5-O-T that can raise up the density of β-endorphin, β-endorphin has analgesic effect. For non-nutritive sucking, it also contains attention transferring. It is said that non-nutritive sucking can raise up the pain threshold through stimulating the oral tactile recipient, or promote the releasing of 5-HT that modulates pain. Non-nutritive sucking can also lower the sensitivity of peripheral nerves.
