Background: The maternal microbiome represents the first microbial environment for the developing infant, with emerging evidence linking maternal dysbiosis to adverse pregnancy outcomes and lifelong offspring health. Aims: This review synthesizes evidence on the maternal-infant microbial continuum, examining microbial dynamics during pregnancy, vertical transmission pathways, infant microbiome trajectories, and intervention strategies. Key Findings: Dynamic changes in maternal gut, vaginal, and oral microbiomes during pregnancy influence fetal development through mechanisms including hormonal modulation (e.g., Clostridium innocuum-mediated 17β-estradiol degradation), immune programming via short-chain fatty acids, and barrier integrity maintenance. Delivery mode exerts persistent effects, with Cesarean-section associated with higher allergy risk (OR=1.5-2.2), while probiotic supplementation may mitigate this risk (RR=0.6-0.8). Conclusion: The maternal-infant microbiome continuum represents a critical therapeutic target. Standardized longitudinal research and personalized intervention strategies are urgently needed to translate mechanistic insights into clinical practice.