Nutrients, cilt.17, sa.11, 2025 (SCI-Expanded)
Background/Objectives: This study aimed to evaluate the supportive role of probiotic supplementation in neonatal weight gain through a meta-analysis of published studies. Given the conflicting results in the literature, the objective was to determine the overall effect size and assess the influence of regional and intervention-specific factors. Methods: A total of 20 studies published between 2011 and 2022 were included, comprising a combined sample size of 3929 neonates. A random-effects model was used to calculate the pooled standardized mean difference (SMD) in neonatal weight gain attributable to probiotic supplementation. Heterogeneity among studies was assessed using the I2 statistic. Subgroup analyses were conducted based on geographic region, probiotic strain, dosage, and treatment duration. Results: The pooled analysis demonstrated a modest but non-significant positive effect on neonatal weight gain (SMD: 0.27; 95% CI: −0.06 to 0.61), with substantial heterogeneity across studies (I2 = 91%). Subgroup analyses indicated that regional variations, particularly in studies conducted in China, were associated with a more favorable effect. However, not all studies reported a benefit; some found no difference or even negative effects, particularly in discharge weight outcomes. Conclusions: Probiotic supplementation shows potential for improving neonatal weight gain, but findings remain inconsistent and heterogeneous. Strain selection, dosage, and treatment duration appear to be critical variables influencing outcomes. Future large-scale, multicenter randomized controlled trials are necessary to develop standardized, evidence-based guidelines for probiotic use in neonatal care.