Maternal influences on oral microbiome development and implications for early childhood health: a systematic review

A deeper understanding of how maternal-infant interactions shape the establishment and diversification of the oral microbiome could have significant clinical applications; however, relatively few studies emphasize early maternal-infant microbial connections. This systematic review provides a longitudinal analysis of oral microbiome development from birth to five years, focusing on the relationship between maternal and infant microbiomes. We conducted a systematic search (June 2025) using keywords "mother," "children," "oral microbiome," and "longitudinal" across PubMed, Cochrane Library, and Embase. Twelve studies fulfilled the inclusion criteria: longitudinal design, healthy mother-child dyads, saliva sample collection, and relevant age range. We excluded review articles, non-English publications, and studies with overlapping data. Results were synthesized by developmental stage and topic. Overall, current literature agrees that the mother is an important source of exposure for initial colonization of the newborn's oral microbiome. Several studies indicated that the oral microbiome at birth is diverse and unspecialized, composed mostly of maternally derived strains. Rapid selection occurs over the first few weeks, as the relative abundances of typical oral bacterial species increase. Throughout the first year, increases in diversity strengthen the resemblance between infant and maternal microbiomes. The microbiome appears to stabilize around 3-5 years. In conclusion, maternal-infant connections play a significant role in influencing oral microbiome development during the first 5 years of life. This review highlights the need for future studies to incorporate larger, longitudinal designs with metadata and advanced tools to clarify the roles of delivery mode, tooth eruption, and parental lifestyle habits in shaping early oral microbiome development.