Analgesia During Heel Lance in Preterm Neonates: A Systematic Review and Meta-Analysis Evaluating Non-nutritive Sucking Interventions

Persistent and early pain experiences, before the full development of the nervous system, can lead to enduring behavioral changes in preterm infants. This systematic review and meta-analysis were conducted to evaluate the effect of non-nutritive sucking (NNS) on pain during heel stick procedures in preterm neonates.

Registered on PROSPERO and following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we systematically searched PubMed/MEDLINE, Embase, Scopus, Web of Science, Cochrane, ISRCTN, ClinicalTrials.gov, the WHO ICTRP, and Google Scholar for RCTs of NNS analgesia in preterm NICU infants up to May. Two reviewers independently screened studies, extracted data, and assessed risk of bias using RoB-2. A meta-analysis was conducted in RevMan 5.3.

From 6,216 articles retrieved, eight RCTs underwent detailed assessment, focusing on 225 preterm neonates, with 116 in the NNS group and 109 in the control group. Male neonates constituted 58.5 percent (n = 131). The findings revealed a statistically significant reduction in pain scores and heart rate (HR) in the intervention group. However, the impact of NNS on oxygen saturation (O₂ sat) was not significant.

These findings support a mechanoreceptor-mediated, gate-control analgesic effect of pacifier use in preterm infants, offering a low-cost, low-risk adjunct to NICU pain management. However, standardized NNS protocols and larger multicenter RCTs are needed to optimize dosing, timing, and long-term outcomes.

The results showed that NNS may be effective in improving heel stick pain and HR. However, the limited quantity and quality of included studies underscore the need for further research to comprehensively analyze the influence of NNS on pain reduction.