Premature babies do not get used to repeated pain, study suggests

New research shows that premature babies don’t get used to frequent pain, as do full-term babies, toddlers and adults.

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The study indicates that if pre-term infants have not yet developed mechanisms that enable them to adapt to moderate pain, medical procedures in the first few weeks of life could potentially have an impact on their development. Could

Led by UCL researchers, it suggests that the ability to get used to repeated pain may develop during the third trimester of pregnancy.

Therefore, premature babies may not develop this ability at the same time as full-term babies.

Lead author Dr Lorenzo Fabrizi, from UCL Neuroscience, Physiology and Pharmacology, said: “The way we can use things can be seen as the simplest example of the plasticity of behavior and the brain, and it is the basis of memory and learning. a fundamental part.

Habituation to pain is important because it enables us to conserve physical, emotional, and cognitive resources in a way that is not unavoidable or life-threatening.

Dr Lorenzo Fabrizi, UCL

“Habituation to pain is important because it enables us to conserve physical, emotional and cognitive resources not to overreact to unavoidable or life-threatening pain.

“Our findings suggest that the ability to acclimatize to repeated pain may develop during the third trimester of pregnancy, so that premature infants have not yet developed the ability to acclimate to full-term pain.” Kids are right from birth.”

The study involved 20 children at University College London Hospital (UCLH).

Half of them were pre-term (and were still tested at less than 35 weeks’ gestational age) while the other half were either born at full term (seven infants) or pre-term but at term age (three infants). Tests were done.

The two groups were comparable in terms of their actual postnatal age, as the mean age of pre-term infants was 14 days, compared to 10 days among the full-term group.

The researchers measured the children’s responses to painful but clinically necessary heel lances (blood tests), which were conducted twice (three to 18 minutes apart) for each child.

While unpleasant and painful diagnostic procedures are necessary for many young infants, they have the potential to affect development, such as altered pain perception, or potentially reduced gray matter or disrupted white matter in the brain.

Dr Mohammed Rupawala, UCL

These tests can elicit adequate pain responses in infants, but it was not known beforehand whether this decreases on repeated tests—the study only included infants who needed a second lance.

The researchers recorded the infants’ brain activity and heart rate, as well as monitoring their facial expressions and response to leg withdrawal.

They found that brain activity was not as strong immediately after the second trial compared to the first, suggesting a habituation response.

However, according to the study, this was only the case for full-term babies.

The researchers found a similar pattern for heart rate and facial expressions, as premature infants responded similarly to both heel spurs, while full-term infants showed habituation to pain.

The habitual response may be due to full-term infants anticipating impending pain when they receive the second test, so their response is less pronounced.

They say that habituation to pain may protect full-term babies, but not those who were pre-term, from possible developmental consequences.

First author Dr Mohammed Rupawala, UCL Neuroscience, Physiology and Pharmacology, said: “Although unpleasant and painful diagnostic procedures are necessary for many young infants, they have the potential to affect development, such as altered pain perception, or Potentially disrupts reduced gray matter or white matter in the brain.

Co-author Dr Judith Meek, consultant neonatologist at UCLH, said: “This work raises awareness of the additional vulnerability of premature babies to pain. Clinicians need to do everything possible to protect them from repeated painful experiences.” Needed.

“It should be regarded as an essential component of brain-oriented neonatal care.”

The study, funded by the Medical Research Council and the European Research Council, is published in Current Biology.