Premature babies may feel pain more as adults

Premature babies who are given painful medical treatment in the first few weeks after birth may grow up to feel pain more intensely than normal in later life, scientists believe.

Premature babies who are given painful medical treatment in the first few weeks after birth may grow up to feel pain more intensely than normal in later life, scientists believe.

A study on laboratory rats has shown that newborns who have painful experiences undergo a permanent rewiring of nerves that makes them more sensitive in adulthood.

The scientists, from the American National Institute of Dental and Craniofacial Research near Washington DC, believe the research shows the need to limit painful treatment given to premature babies.

The wider use of heel sticks to draw blood, intravenous drips and other invasive procedures to keep premature babies alive may be producing a generation who are more pain-sensitive than the rest of the population, the scientists warn.

Mary Ann Ruda, lead author of the study, which was published in the journal Science, cautioned that animal research findings had yet to be linked directly to human infants. She said: "A premature infant can be thought of as still in the foetal time of life, when the basic elements of brain development are occurring."

The research focused on the growth in the density of nerve fibres within one of the main "sensory highways" of the spinal cord. Rats who suffered pain soon after birth had more nerve fibres in this region and reacted far more strongly to pain than control animals. The scientists believe this supports the view that the sensory pathways can be permanently re-wired when a newborn baby experiences unusual pain.

Human pain-detection systems begin to develop at 24 weeks' gestation, and continue to develop postnatally, but pain-suppression pathways only develop several weeks after birth.