We aimed to determine if maternal consumption of artificially sweetened beverages (ASB) during pregnancy is associated with modifications of infant gut bacterial community composition and development during the first year of life, and whether these alterations are linked with infant body mass index (BMI) at one year of age.. CHILD ARTIFICIAL SWEETENERS AND MICROBIOME

Importance: Artificial sweetener consumption by pregnant women has been associated with an increased risk of infant obesity, but the underlying mechanisms are unknown.Objective: We aimed to determine if maternal consumption of artificially sweetened beverages (ASB) during pregnancy is associated with modifications of infant gut bacterial community composition and development during the first year of life, and whether these alterations are linked with infant body mass index (BMI) at one year of age.Design, settings, and participants: This secondary analysis includes 100 infants from the prospective Canadian CHILD Cohort Study, selected based on maternal ASB consumption during pregnancy (50 non-consumers and 50 daily consumers). Infant stool samples were acquired in early (3-4 months) and late (12 months) infancy.Exposure(s) (for observational studies): Maternal ASB consumption captured from food frequency questionnaires during pregnancy.Main Outcome(s) and Measure(s): Infant gut bacterial community determined by next-generation sequencing of 16S rRNA gene amplicons, and infant BMI z-score at one year of age, defined according to the World Health Organization reference.Results: We identified four microbiome clusters, of which two recapitulated the maturation trajectory of the infant gut bacterial communities from immature (Cluster 1) to mature (Cluster 4) and two (Cluster 2-3) deviated from this trajectory. Maternal ASB consumption did not differ between clusters, but was associated with community-level shifts in infant gut bacterial taxonomy structure within Cluster 2, and with depletion of several Bacteroides sp. BMI was higher among infants exposed to maternal ASB consumption, and gut bacterial community structure was significantly associated with infant BMI. Conclusions and Relevance: Gestational exposure to ASB is associated with gut microbiota structure in some infants, and gut microbiota structure is associated with variation in infant BMI. As we face an unprecedented rise in childhood obesity, future studies should evaluate the causal role of gut microbiota in the association between maternal ASB consumption, infant development and metabolism, and body composition; and knowledge of the gut microbiota may identify novel approaches to mitigate this risk.