The Effects of Breastfeeding and the Taste and Smell of Breast Milk on Pain Reduction in Infants: An Umbrella Review and Reanalysis of Meta-Analytic Evidence

BACKGROUND: Painful procedures are frequently performed in neonatal care, yet their repeated exposure is associated with adverse short- and long-term neurodevelopmental outcomes. Nonpharmacological, physiological, and parent-involved interventions such as breastfeeding and breast milk sensory stimuli have emerged as promising strategies for procedural pain management. OBJECTIVE: This umbrella review and meta-analytic reanalysis aimed to synthesize the evidence from systematic reviews and meta-analyses evaluating the analgesic effects of breastfeeding, breast milk odor, and breast milk taste during painful procedures in term and preterm infants. METHODS: A comprehensive umbrella review approach was applied, and the methodological quality of all included reviews was assessed using the Assessment of Multiple Systematic Reviews-2 tool. Effect sizes from existing meta-analyses were reanalyzed using random-effects models, incorporating heterogeneity, prediction intervals, and clinical variation across interventions and populations. RESULTS: Breastfeeding demonstrated the strongest analgesic effect, with large reductions in pain scores, crying duration, and heart rate during procedural pain. Breast milk odor and taste also reduced behavioral and physiological pain indicators, particularly among preterm infants, though with smaller effect sizes compared with direct breastfeeding. Despite generally consistent effect directions, substantial heterogeneity was observed across meta-analyses due to variation in populations, procedures, intervention timing, and outcome measures. High-quality Cochrane reviews contributed the strongest evidence base, while non-Cochrane reviews showed moderate-to-low methodological confidence due to limitations such as lack of protocol registration or incomplete reporting. CONCLUSIONS: Breastfeeding and breast milk-related sensory interventions are effective, feasible, and safe nonpharmacological strategies for managing procedural pain in neonates. These findings support the integration of breastfeeding or maternal milk sensory exposure as first-line approaches in neonatal pain management protocols. Further research is needed to clarify optimal timing, dosing, and combinations with other nonpharmacological interventions.