MILK-INDUCED HYPOALGESIA IN HUMAN NEWBORNS

Objective. To determine whether milk and its components reduce crying in newborns during and after blood collection for phenylketonuria eval uation. Methodology. Seventy-two normal newborns ingested 2 mL of milk (Similac), Ross Special Formula, fat, protein, lactose, sucrose, or w ater for the 2 minutes preceding blood collection via heel lance. Cryi ng duration during and for the 3 minutes after the procedure was deter mined by scorers who were blind to the ingestive substance. Results. S ucrose and Similac each reduced crying during the blood collection pro cedure. Sucrose, fat, protein, and Ross Special Formula were effective during the 3-minute recovery period. Neither water nor lactose were e ffective during or after blood collection. Conclusion. Milk and some o f its components are antinociceptive in human newborns. Based on previ ous studies, reduced crying during and after painful stimulation may b e mediated through endogenous opioids. These findings are of potential clinical significance: natural protective mechanisms, normally engage d during suckling, may safely and noninvasively be activated to reduce newborn crying to painful stimulation.