Premature babies feel pain, but can't say ouch

By Steve Connor

Premature babies feel pain according to a study that objectively measured for the first time how the brain of very young babies responds to painful medical procedures.

Doctors have long debated whether the cries and grimaces of premature babies are reflex responses or something more akin to the true pain experienced by older children.

Research on 18 premature and full-term babies has probably resolved the debate by analysing the nerve activity in those parts of the brain that are stimulated during the conscious awareness of pain.

The scientists analysed the flow of oxygenated blood to the sensory areas of the brain when the babies were going through the procedure for taking a sample of blood, which involves sticking small needles into their heels.

"Most people intuitively feel that premature babies feel pain but the problem is that we have not actually known whether they do so or not," said Professor Maria Fitzgerald of University College London, who led the study published in the Journal of Neuroscience.

"Premature babies have only a limited repertoire of behaviour, so the question is how much pain are they actually feeling when they undergo hospital procedures," Professor Fitzgerald said.

"It has in the past been impossible to measure pain objectively in premature babies. What we have done for the first time is to measure the activity of nerve cells in the brain that are known to be stimulated by pain," she said.

The babies were aged between 25 and 45 weeks after conception and were monitored immediately before, during and after a routine blood test.

Even the youngest babies showed signs of being consciously aware of the pain caused by the needle stick, the study found.

"The importance of this is clear. The United Kingdom has the highest rate of low birth-weight babies in Western Europe. About 12 per cent of all babies born need some level of care at birth and 2.5 per cent need neonatal intensive care."

"Since pain information is transmitted to the pre-term infant's brain cortex from 25 weeks there is the potential for pain experience to influence brain development from a very early age as the brain is highly malleable at this stage of development," Professor Fitzgerald said.

Each premature baby in intensive care is subjected to an average of 14 procedures a day - many of which are considered painful - such as heel pricking or inserting chest tubes, the study found.

"The problem is that premature babies are not under anaesthesia, they are awake and they have to have a lot of procedures carried out on them all the time."

"What they need is analgesia - pain-relieving drugs that won't knock them out," she said.

Although the study shows that premature babies as young as 25 weeks feel pain, the findings cannot be used to suggest that aborted foetuses also feel pain.

"This study casts no light on the abortion issue because it was done on premature babies," Professor Fitzgerald said.

The premature-baby charity Bliss said the findings show there is a need to establish ways of alleviating the pain experienced by premature babies during medical procedures.

The charity said that only 20 per cent of neonatal units in Britain regularly assess chronic pain and more attention should be paid to providing comfort and relief when painful procedures are undertaken.

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