Background : Preterm neonates are more sensitive to pain. Early pain stimulation may influence the developing brain and thereby neurodevelopment and behaviors on preterm neonates. Previous studies have shown that the use of olfactory stimuli during painful medical procedures reduces neonates response to pain. The main purpose of this study was to investigate the analgesic effect of maternal breast milk odor on preterm neonatal pain response undergoing invasive procedures.
Material : Thirty preterm infants born between 28 weeks and 35 weeks + 6 day gestation and being more than 5 days postnatal age were assigned into two groups. Infants in the first group were exposed to breast milk odor and the second group were exposed to formula milk odor from 5 minutes prior to heel prick test until 30 seconds after. The pain score was measured using Neonatal Infant Pain Scale (NIPS). We evaluated heart rate, respiratory rate, and peripheral oxygen saturation prior to and after heel lancing.
Results : Our study included 17 neonates in the maternal breast milk odor group and 13 in the formula milk odor group. After the heel lancing, NIPS score was found to be significantly lower in the breast milk group than the formula milk group (2.29 compared to 3.15 with p < 0.05). Statistical analyses showed that in breastmilk group there were no significant differences of heart rate, respiratory rate, and peripheral oxygen saturation after heel lancing compared to its baseline (p 0.055; p 0.083; p 0.332). This result showed that maternal breastmilk odor has an analgesic effect on preterm neonates.
Conclusions : Maternal breast milk odor has an analgesic effect on preterm neonates and can be used as a safe method for pain relief.