The following is a summary of “Effect of breast milk odor on infant pain and stress levels: a systematic review and meta-analysis,” published in the February 2025 issue of BMC Pediatrics by Laleh et al. 

Managing neonatal pain and stress is essential. Maternal odor shows potential, but evidence is mixed. 

Researchers conducted a prospective study to assess breast milk odor’s effect on neonatal pain, stress, oxygen saturation (SpO2) and heart rate (secondary outcomes).  

They searched PubMed, Cochrane, SID, Embase, and Google Scholar until January 14, 2025, with no time restrictions. A meta-analysis compared intervention and control groups, assessing heterogeneity using I² and chi-squared tests. A random effects model was applied for high heterogeneity (I² ≥ 30%, P < 0.05), analyzing continuous outcomes with mean difference (MD) and standardized mean difference (SMD) at a 95% CI. Subgroup analyses were conducted based on newborn procedures and term status, along with meta-regression and sensitivity analyses. Trial Sequential Analysis (TSA) ensured reliability, and evidence certainty was evaluated with GRADE. 

The results showed that seven studies (RCT and quasi-experimental) found breast milk odor significantly reduced neonatal pain (SMD: -1.60, 95% CI: -2.48, -0.72; I² = 94%; 7 trials; 478 neonates; low-certainty). It improved oxygen saturation (MD: 1.64, 95% CI: 0.49, 2.80; I² = 57%; 5 trials; 288 neonates; very low-certainty) and heart rate (MD: -6.73, 95% CI: -12.33, -1.13; I² = 78%; 5 trials; 288 neonates; very low-certainty). Stress reduction was noted but not significant (MD: -0.64, 95% CI: -1.87, 0.59; I² = 89%; 2 trials; 128 neonates; very low-certainty). Meta-regression showed cesarean delivery rates significantly correlated with pain response (P = 0.010). TSA confirmed sufficient power for pain outcome analysis. 

Investigators found breast milk odor had potential for neonatal pain management, but low to very low certainty of evidence required further research for validation. 

Source: bmcpediatr.biomedcentral.com/articles/10.1186/s12887-025-05504-z