“…Preclinical animal models have shown that pioneer communities, such as those from the maternal cervicovaginal and gut microbiota, colonize the mucosal surfaces of the newborn and initiate processes that include immune system maturation, nutritional provisioning for the developing brain, and other adaptations to the postnatal environment (Arrieta et al, 2015; Fulde et al, 2018; Gensollen et al, 2016; Jašarević and Bale, 2019; McDonald and McCoy, 2019; Renz et al, 2018; Walker, 2017). Indeed, these animal studies have shown that disruption in this intestinal colonization process promotes lasting changes to the offspring’s immune system, hypothalamic-pituitary-adrenal stress axis, as well as increased susceptibility to allergy, obesity, and diabetes across the lifespan (Al Nabhani et al, 2019a, 2019b; Arrieta et al, 2015; Jašarević et al, 2015, 2017, 2018; Morais et al, 2020; Sudo et al, 2004). While such studies support the notion that vertical transmission of maternal microbiota impacts offspring development in a composition-dependent manner, the specific health outcomes following colonization by a nonoptimal CST IV cervicovaginal microbiome, especially in the context of a high-risk pregnancy, have not been examined.…”