Impact of Breast Milk on Cortical Pain Response in Newborns

During the first few days of life, newborns are exposed to painful and stressful procedures.1, 2 One of these is the metabolic disease screening test using the heel-prick procedures.3, 4 Newborn screening is crucial to detect several congenital genetic and metabolic disorders at an early stage for the earliest possible recognition and management of affected newborns and to prevent morbidity, mortality, and disabilities associated with inherited metabolic disorders5. Pain induced by these procedures is ineffectively prevented or inadequately treated1. Consequently, this may have short- and long-term negative effects on the pain response and neurodevelopmental outcomes.6, 7, 8 Thus, effectively identifying, assessing, and managing neonatal pain are crucial to minimizing its impact on the intermediate- and long-term outcomes in newborns.2, 9 Near-infrared spectroscopy (NIRS) is a noninvasive technique widely used in neonatal pain research to measure functional activation of the cortex.20, 21, 22, 23 NIRS has revealed that blood sampling can activate the neonatal somatosensory20, 21, motor24, and prefrontal22 areas starting at the 25th week of postmenstrual age. Pain increases oxygen consumption with changes occurring in the primary somatosensory cortex on the brain surface.25, 26 Additionally, the relationship between the total Premature Infant Pain Profile (PIPP)27 score and hemodynamic response has been evaluated. Among the analgesics studied for neonatal pain, breast milk is a natural substance beneficial and nutritious for infants.32 Whether breast milk administration alters cortical brain activation in neonates is presently unclear. Therefore, we conducted a trial to assess whether breast milk can relieve cortical pain during a painful metabolic disease screening procedure.