Maternal probiotic supplementation and offspring health: an umbrella review with re-analysis of systematic reviews and meta-analyses

Background The maternal gut microbiota critically influences offspring colonization and long-term health. Probiotics have attracted significant attention due to their microbiota-modulating potential. However, the lack of clear international guidelines for their use in pregnancy and lactation underscores the need for robust evidence on safety and the impact of maternal supplementation on offspring health. Objective We conducted an umbrella review (UR) of systematic reviews (SRs) with meta-analyses (MAs) to evaluate the quality, certainty, and credibility of evidence regarding the effects of maternal probiotic supplementation during pregnancy and/or lactation on offspring health. Methods We searched PubMed, Embase, CINAHL, Web of Science, and Cochrane Library up to June 15, 2025, for peer-reviewed SRs. Summary effects were re-estimated using random-effects models. Quantitative evidence quality was appraised with AMSTAR-2 and certainty graded using GRADE. Outcomes from single primary studies or with unextractable data were summarized narratively. Results Eighteen SRs were included, of which 13 provided MAs with ≥2 original studies, encompassing 62 specific offspring-related outcomes. Among these, three types of outcomes were rated as having moderate to high certainty by GRADE. Maternal probiotic supplementation was associated with lower risks of eczema or atopic eczema in offspring, primarily within the first 1–2 years of life (e.g., RR = 0.52, 95% CI: 0.38 to 0.72; p 0.001), and decreased abundance of pathogenic bacteria in breast milk (e.g., SMD = −0.90, 95% CI: −1.49 to −0.31; p = 0.003). Nevertheless, according to the UR credibility criteria, all statistically significant associations were rated as having weak credibility. Sensitivity analyses using more conservative methods showed that 65% of these associations lost significance, though the associations with eczema and breast milk microbiota improvement remained significant. Conclusion Current evidence remains insufficient to confirm benefits or harms of maternal probiotic supplementation. Although statistical associations were observed for eczema risk and pathogenic bacteria in breast milk, weak credibility of these findings necessitates further robust studies to verify these effects. Systematic review registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420251120972 , PROSPERO CRD420251120972.