Non-nutritive sucking for increasing physiologic stability and nutrition in preterm infants

Non-nutritive sucking (NNS) is used during gavage feeding and in the transition from gavage to breast/bottle feeding in preterm infants to improve the development of sucking behavior and the digestion of enteral feedings.

To assess the effects of non-nutritive sucking on physiologic stability and nutrition in preterm infants.

We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1), MEDLINE via PubMed (1966 to 25 February 2016), Embase (1980 to 25 February 2016), and CINAHL (1982 to 25 February 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials.

Randomised controlled trials and quasi-randomised trials that compared non-nutritive sucking versus no provision of non-nutritive sucking in preterm infants. We excluded cross-over trials.

Two review authors assessed trial eligibility and risk of bias and undertook data extraction independently. We analysed the treatment effects in the individual trials and reported mean differences (MD) for continuous data, with 95% confidence intervals (CIs). We used a fixed-effect model in meta-analyses. We did not perform subgroup analyses because of the small number of studies related to the relevant outcomes. We used the GRADE approach to assess the quality of evidence.

We identified 12 eligible trials enrolling a total of 746 preterm infants. Meta-analysis, though limited by data quality, demonstrated a significant effect of NNS on transition from gavage to full oral feeding (MD -5.51 days, 95% CI -8.20 to -2.82; N = 87), transition from start of oral feeding to full oral feeding (MD -2.15 days, 95% CI -3.12 to -1.17; N = 100), and the length of hospital stay (MD -4.59 days, 95% CI -8.07 to -1.11; N = 501). Meta-analysis revealed no significant effect of NNS on weight gain. One study found that the NNS group had a significantly shorter intestinal transit time during gavage feeding compared to the control group (MD -10.50 h, 95% CI -13.74 to -7.26; N = 30). Other individual studies demonstrated no clear positive effect of NNS on age of infant at full oral feeds, days from birth to full breastfeeding, rates and proportion of infants fully breastfeeding at discharge, episodes of bradycardia, or episodes of oxygen desaturation. None of the studies reported any negative outcomes. These trials were generally small and contained various methodological weaknesses including lack of blinding of intervention and outcome assessors and variability on outcome measures. The quality of the evidence on outcomes assessed according to GRADE was low to very low.

Meta-analysis demonstrated a significant effect of NNS on the transition from gavage to full oral feeding, transition from start of oral feeding to full oral feeding, and length of hospital stay. None of the trials reported any adverse effects. Well-designed, adequately powered studies using reliable methods of randomisation, concealment of treatment allocation and blinding of the intervention and outcome assessors are needed. In order to facilitate meta-analysis of these data, future research should involve outcome measures consistent with those used in previous studies.