Effect of biotic supplementation on infant sleep and settling behaviours: A systematic review and meta-analysis.

Microbiota changes throughout infancy and can be modified by biotic supplementation, which includes probiotics, prebiotics, synbiotics, and post-biotics. Given the potential influence of the microbiome on infant sleep, this systematic review and meta-analysis aimed to determine the effect of biotic supplementation on sleep behaviours in full-term infants aged 0-12 months. In June 2023, we searched seven databases for randomised controlled trials (RCTs) of biotic supplementation intervention studies using synonymous terms for 'infant' AND 'biotic' AND 'sleep' (PROSPERO registration ID: CRD42022358822). Title/abstracts and the full texts were independently screened. Data on infant sleep and settling behaviour outcomes, reported adverse/side effects, and co-morbid conditions were extracted for analysis. Using the modified Cochrane Collaboration tool, two independent reviewers judged the risk of bias. Meta-analyses were conducted using RevMan5. Our search yielded 453 unique studies and 23 RCTs are included in this review. Probiotic supplementation was the most common biotic supplementation (provided in 53% of studies), while 28% and 19% offered prebiotic and synbiotic supplementation, respectively. Sleep duration was the most common (95%) reported outcome for probiotics. No significant differences were reported in sleep duration during the 1st to 4th week of probiotic supplementation. However, in the 5th week of probiotic supplementation, infants who received placebo slept significantly longer (MD = -35.17 min, 95% CI [-69.72, -0.62]), suggesting a borderline significance that is clinically relevant. There were limited studies and timeframe alignment to analyse prebiotics, synbiotics, post-biotics, and para-probiotics effects on infant sleep duration. The study suggests probiotic supplementation does not increase infant sleep duration within the first 4 postpartum weeks and may contribute to reduced sleep duration in the fifth week. Limited studies were available to assess the effects of biotic supplementation over the first 12 postpartum months. Future research should assess the full range of sleep behaviours, infant feeding type, and microbiome.