Maternal and Infant Skin Microbiome Synchrony and Divergence: A Longitudinal Study of Skin Microbial Ecology and Early-Life Assembly.

During pregnancy and after childbirth, women's skin undergoes significant changes which may affect the skin's functional and structural characteristics and microbial diversity. Like their mothers, the newborns also experience various skin challenges in the months following birth. Temporal changes in skin microbiome in special groups such as pregnant women and newborns, as well as the interrelation between their skin's microbial diversity, have not been investigated. We followed women from pregnancy through 6 months after delivery, and their infants from 4 weeks to 6 months of age to investigate their skin characteristics and the microbiome, and potential associations. We enrolled 109 pregnant females residing in Berlin, Germany, with 93 mothers-infant pairs completing the study. Microbiome investigations included DNA isolation as single-site sampling using volar forearm skin swabs. Bioinformatic analysis involved OTU clustering at 97% sequence identity, taxonomic assignment using NCBI reference databases, and calculation of biodiversity metrics, including relative abundance of the dominant bacterial phylotypes, bacterial diversity and Shannon diversity index. The maternal skin microbiome showed mild to moderate changes throughout pregnancy and the 6 months postpartum period. In infants, alpha diversity significantly increased (mean species richness from 82.6 at 4 weeks to 116.1 at 6 months), although it did not reach maternal diversity levels (145.4 at 6 months postpartum). Regarding the microbiome consistency of the included women and infants, the within-pair similarity was always significantly higher than between-pair similarity for both time points. Therefore, we conclude that there is likely a relationship between the microbiome of the mother and that of her child.