Pain pathways are developed by late gestation, which allow the foetus to perceive pain.
Premature and sick term infants regularly experience painful and stressful procedures
There is
evidence that brain development is affected by stress and pain.
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The effects of stress can be more prolonged than acute pain. Carbejel et al found that preterm
infants experienced between 2- 10 painful procedures a day on ITU, while Newham eta al found
that infants experienced multiple stress experiences a day, ranging from nappy changes to eye
examinations.
Studies in both animals and humans have demonstrated long term adverse effects following
prolonged or repeated exposure to pain in the neonatal period. This includes altered behavioural
responses to pain, which may persist through childhood and beyond. ( Anand, Granau,Taddio et al).
It is often difficult to differentiate between pain and stress in preterm infants, as their behavioural
response is also immature.