In a new study published in Nature Communications, researchers observed 65 newborn babies who had received a standard heel-prick blood test to look for signs of potential infection. When a baby’s blood test result suggested they may have an infection, which required further antibiotic treatment, the researchers continued to look for signs of pain or discomfort.
They found that babies with laboratory markers of inflammation associated with infection (raised C-Reactive Protein, (CRP) levels in blood) displayed more sensitivity to pain. This was measured by recording changes in each baby’s brain activity, leg reflex withdrawal activity, facial expression and heart rate in response to a clinically-required heel prick blood test.
These babies were also more sensitive to touch, which is consistent with clinical reports that infections can make babies more irritable. While behavioural signs of pain, such as facial grimacing, did not appear to be exaggerated by the presence of inflammation, this may be because fighting an infection can cause babies to be more lethargic and fatigued.