Background: Current research suggests a need to implement environmental, behavioral, and even nutritional interventions, with the objective of improving the comfort and stability of preterm newborn infants, as well as reducing their stress and pain levels. Several studies have used the salivary reactivity of cortisol to assess stress or pain in preterm infants. The aim of this study was to analyze the results of published randomized controlled trials that tested the effects of nonpharmacological interventions on cortisol as a treatment for heel lance pain/stress in preterm infants.
Methods: Published randomized controlled trials (RCTs) were searched in PubMed, Embase, CINHAL, Web of Science Cochrane Library, and Cochrane Database of Systematic Reviews, and six studies met the eligibility criteria. The quality of the included studies was appraised using Cochrane's Collaboration tool.
Results: The meta-analysis showed that non-pharmacological interventions were associated with a reduction in levels of salivary cortisol in comparison with other interventions and controls, with fixed effect mean differences of -0.11, and with a 95% C.I. of -0.28 to -0.05. Prone-nest position, breast milk odor, kangaroo care, and twins co-bedding led to a decrease in cortisol levels in saliva.
Conclusion: Future studies should be performed on nonpainful interventions in order to gain more knowledge about the regulation of cortisol in saliva in preterm infants with involving control group and larger sample sizes.
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