The Calming Effect of Maternal Breast Milk Odor on Term Infant: A Randomized Controlled Trial.

This study was carried out to assess the effect of the odor of breast milk and formula milk on reducing the acute pain of newborn infants during the heel-prick blood sampling. Eighty-four newborn were randomly assigned into two groups (formula milk group and breast milk group) with 42 infant searches. The pain that the newborn felt before, during, and after heel-prick blood sampling was assessed using Neonatal Infant Pain Scale; their heart rate and blood oxygen saturation were measured with a pulse oximeter. Saliva samples were taken from newborns before and after sampling, and their salivary cortisol level was measured. During sampling, the crying duration of newborn was recorded with a chronometer. The pain threshold and heart rates of the newborn in the breast milk group were significantly lower than those in the formula milk group ( < 0.001). Salivary cortisol in the formula milk group increased and oxygen saturation levels in these infants decreased significantly more as compared to the breast milk group ( < 0.05). The odor of breast milk may be helpful in reducing the pain of newborn during heel-prick blood sampling.