[1] It was only in the last quarter of the 20th century that scientific techniques finally established babies definitely do experience pain – probably more than adults – and developed reliable means of assessing and of treating it.
There are a number of metabolic and homeostatic changes which result from untreated pain, including an increased requirement for oxygen, accompanied by a reduction in the efficiency of gas exchange in the lungs.
[4] The neuropsychological effect on the bonding between mother and child, on later contact with health professionals, and on personal and social psychological well-being is difficult to quantify.
[7] The neural pathways that descend from the brain to the spinal cord are not well developed in the newborn, resulting in the ability of the central nervous system to inhibit nociception being more limited than in the adult.
[8] There are also indication that the neonate's nervous system may be much more active than that of an adult, in terms of transforming its connections and central nerve pathways in response to stimuli.
The ongoing process of neural pathway development, involving both structural and chemical changes of the nervous system, have been shown to be affected by pain events, both in the short term and potentially into adult life.
The baby is crying and irritable when awake, develops a disturbed sleep pattern, feeds poorly, and shows a fearful, distrustful reaction towards care-givers.
Combinations of crying with facial expressions, posture and movements, aided by physiological measurements, have been tested and found to be reliable indicators.
[16] Where the baby is to undergo some form of planned procedure, health professionals will take steps to reduce pain to a minimum, though in some circumstances it may be not be possible to remove all pain.[which?]
In case of illness, accident and post operative pain, a graded sequence of treatment is becoming established as standard practice.
Touching, holding, stroking, keeping warm, talking and singing/music are ways in which adults have been comforting babies since the start of human history.
It is, therefore, considered good practice to involve parents or care-givers directly, having them present and in contact with the baby whenever possible before a minor painful procedure, such as the drawing of blood, or prior to giving a local anaesthetic injection.
It does not moderate the effect of pain on heart rate[23] and a recent single study found that sugar did not significantly affect pain-related electrical activity in the brains of newborns one second after the heel lance procedure.
[24][25] Sweet oral liquid moderately reduces the incidence and duration of crying caused by immunization injection in children between one and twelve months of age.
[29] The "3Ts" stimuli (touch, talk, and taste) given throughout the painful procedure increase the well-known analgesic effect of oral sugar.
Regional anaesthesia requires the injection of local anaesthetic around the nerve trunks that supply a limb, or into the epidural space surrounding the spinal cord.
There are three forms of analgesia suitable for the treatment of pain in babies: paracetamol (acetaminophen), the nonsteroidal anti-inflammatory drugs, and the opioids.
Doris Cope[37] quotes paediatric surgeon Felix Würtz[38] of Basel, writing in 1656: If a new skin in old people be tender, what is it you think in a newborn Babe?
Scientific studies on animals with various brain lesions were interpreted as supporting the idea that the responses seen in babies were merely spinal reflexes.
and publications on the hormonal and metabolic responses of babies to pain stimuli began to appear, confirming that the provision of adequate anaesthesia and analgesia was better medicine on both humanitarian and physiological grounds.