Background: Non-nutritive sucking is used during gavage feeding and in the transition from gavage to breast/bottle feeding in preterm infants. The rationale for this intervention is that non-nutritive sucking facilitates the development of sucking behaviour and improves digestion of enteral feedings. Non-nutritive sucking has been considered to be a benign intervention, although it has the potential to have a negative effect on breastfeeding or on the incidence of later oral aversion.
Objectives: To determine whether non-nutritive sucking (NNS) in preterm infants influences: a) weight gain, b) energy intake, c) heart rate, d) oxygen saturation, e) length of hospital stay, f) intestinal transit time, g) age at full oral feeds, or h) any other clinically relevant outcomes.
Search strategy: MEDLINE and CINAHL databases back to 1976 and The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2005) were searched. The EMBASE database was added to the search strategy for 2005. Reference lists/bibliographies of relevant articles and reviews were also searched. A comprehensive list of relevant articles was sent to two major authors in this area. They were asked if they knew of any other published or unpublished studies relevant to the area that had not been included in the original list.
Selection criteria: All trials utilizing experimental or quasi-experimental designs in which non-nutritive sucking in preterm infants was compared to no provision of non-nutritive sucking. Measured clinically relevant outcomes. Reports were in English or a language for which a translator was available.Computerized searches were conducted by both reviewers. All potentially relevant titles and abstracts identified by either reviewer were extracted. All retrieved articles were assessed for relevance independently by each reviewer, based on a pre-determined set of criteria. The reference lists/bibliographies of each article were reviewed independently for additional relevant titles and were also retrieved and assessed for relevance. Articles that met all relevance criteria were then assessed for methodologic quality based on a predetermined set of criteria. Those articles judged to have the appropriate quality by both reviewers were included in the analysis.
Data collection and analysis: Data were extracted independently by the two authors. No subgroup analyses were performed because of the small number of studies related to the relevant outcomes.
Main results: This review consisted of 21 studies, 15 of which were randomized controlled trials. NNS was found to decrease significantly the length of hospital stay in preterm infants. The review did not reveal a consistent benefit of NNS with respect to other major clinical variables (weight gain, energy intake, heart rate, oxygen saturation, intestinal transit time, age at full oral feeds and behavioral state). The review identified other positive clinical outcomes of NNS: transition from tube to bottle feeds and better bottle feeding performance. No negative outcomes were reported in any of the studies.
Authors' conclusions: This review found a significant decrease in length of stay in preterm infants receiving a NNS intervention. The review did not reveal a consistent benefit of NNS with respect to other major clinical variables (weight gain, energy intake, heart rate, oxygen saturation, intestinal transit time, age at full oral feeds and behavioral state). The review identified other positive clinical outcomes of NNS: transition from tube to bottle feeds and better bottle feeding performance. No negative outcomes were reported in any of the studies. There were also a number of limitations of the presently available evidence related to the design of the studies, outcome variability, and lack of long-term data. Based on the available evidence, NNS in preterm infants would appear to have some clinical benefit. It does not appear to have any short-term negative effects. In view of the fact that there are no long-term data, further investigations are recommended. In order to facilitate meta-analysis of these data, future research in this area should involve outcome measures consistent with those used in previous studies. In addition, published reports should include all relevant data.