Functional neuroimaging of breastfeeding analgesia by multichannel near-infrared spectroscopy.

BACKGROUND

Newborns perceive pain, and several non-pharmacologic analgesic methods have been used during painful procedures. Activation of the neonatal somatosensory cortex, in association with a painful procedure without analgesia, has been demonstrated by two-channel near-infrared spectroscopy (NIRS).

OBJECTIVES

To evaluate both cortical and behavioural responses of healthy term newborns to a painful procedure during two non-pharmacologic analgesic interventions, i.e. glucose solution and breastfeeding.

METHODS

The effects of glucose and breastfeeding on pain-associated neonatal cortical activity were studied in two groups (n = 30) by multichannel NIRS during a heel prick. Cortical activation was identified by variations in oxygenated haemoglobin. Neonatal pain expression was assessed by a validated scale.

RESULTS

No significant variations in cortical activity emerged using glucose solution, whereas breastfed newborns showed widespread cortical activation. Breastfed neonates showed significantly less behavioural pain expression.

CONCLUSIONS

Glucose is associated with no significant cortical activation and may interfere with pain-associated response at the cortical level. Conversely, breastfeeding analgesia is associated with generalized cortical activation and may act by multisensory stimulation, possibly overwhelming pain perception.