The five “S’s” and the “SNOO” Smart Sleeper—non-pharmacological interventions (NPI) to promote sleep and reduce crying of infants: a scoping review

BACKGROUND: Sleeping and crying are normal activities of infants. Infant crying and night wakings can be both distressing and exhausting for parents. At its worse it may be associated with an increased risk of maternal depression and psychosocial stress for both parents. Strategies for reducing crying and improving sleep include the five “S’s”—swaddling, side/stomach position, sucking, swinging and shushing sounds simulating “womb-like” sensations. The “SNOO” Smart Sleeper (SNOO), a “smart” bassinet, incorporates 3 of the five “S’s”, swaddling, swinging (rocking) and emits soothing sounds while demonstrating safe infant sleep practices. This paper explores the effectiveness of the five “S’s” and the SNOO. METHODS: References for the five “S’s” were obtained from various sources while a scoping review of publications from PubMed, Embase and Web of Science was undertaken to seek out relevant studies to document the efficacy of the SNOO. RESULTS: The five “S’s” appear to help soothe infants, reduce their crying and improve their sleep. In addition, infant obesity rates fell. Infants also experienced less pain following immunisations. Of the 66 papers gleaned from the database in mid-2021 for the scoping review, only those which provided clear outcomes and conclusions, were complete and related to infants were included. That resulted in only 2 studies that fitted the criteria imposed. They suggested that the SNOO incorporating 3 of the five “S’s” had similar beneficial effects. CONCLUSIONS: The five “S’s” were effective non-pharmacological strategies to help reduce crying and improve sleep in infants. Confounding factors included normal crying of infants, triggers of hunger or tiredness, or recognised causes of crying. The 2 studies reviewed suggested that the SNOO was helpful in reducing crying and improving the sleep duration of normal infants. Further studies have suggested it may be used therapeutically for distressed or ill infants.