Olfactory Stimulation by Breast Milk Odor May Improve Behavioral Feeding in Preterm Infants: A Review

Background: The interaction between premature infants and the ectopic environment requires special care due to developmental defects in various systems of their body. In this regard, the results of various studies have introduced the stimulation of premature infants with the smell of breast milk as an effective way to improve the physiological responses caused by prematurity and reduce the problems associated with prematurity. The aim of this study was to systematically review the intervention studies of aromatherapy with breast milk on improving behavioral and physiological responses and reducing prematurity problems in premature infants. Method: A comprehensive search of related scientific studies, published until February 2020, was conducted in scientific databases of PubMed, ISI, Web of Science, Cochrane Library, and Scopus using the following keywords: Breast Milk, Maternal Milk odor, Mother's Milk, Mother's odor, Premature Birth, Olfactive stimulation, Pain, Aromatherapy, Apnea, Preterm infant, Preterm infant pain, Infant behavior, Infant physiological response. After applying the entry and exit criteria, 14 Articles were selected. Results: The results revealed a decrease in transition feeding days in premature infants of the intervention group in exposure to an impregnated pad with breast milk as olfactory stimulation, when compared to the control group. Based on the results, longer sucking bouts, more bursts (>7 sucking movements) and more consumed milk were reported for the intervention group during each breastfeeding session, when compared to the control group. The frequency of sucking in response to fresh breast milk was also higher than frozen breast milk, but not statistically significant (p = 0.09). There was an elevation in the high-amplitude non-nutritive sucking frequency among the preterm infants within the last three days of 14-day study after presenting the odor of the maternal breast milk for a 60-second period. Beneficial effects occurred in the hospitalized infants due to the odor of mother; they included increasing mouth movements and pacifier acceptance, calming stressed or crying infants, and relieving their pain. The infant's ability to feed increases and the duration of the first lactation decreases due to the olfactory stimulation of the breast milk odor; and the number of sucks (260.4 [95% CI = 206-315]) and suck bursts (41.0 [95% CI = 36-46]) was unexpectedly observed in group 1 (breast milk odor), as compared to group 2 (144.8 [95% CI = 87-203] versus 27.4 [95% CI = 21-34]) Conclusion: This study showed that the use of aromatherapy with the mom's milk is very effective in improving the behavioral and physiological response; and reduces the problems resulting from prematurity in premature babies. Therefore, the smell of breast milk can be used as a complementary method to accelerate the health promotion of premature infants.