Stress exposure influenced the maternal gut microbiota; no significant difference was found in the placental microbiota composition. PNS-E mice presented higher Bacteroides and Firmicutes expression as compared to CON; at the family level, a relative increase of the Bifidobacteriaceae, and RIkenellaceae was described. Prenatal stress exposure resulted in increased anxiety-like behaviors and neophobia. Stress exposure resulted in reduced BDNF placental levels and higher levels of IL-1β in placental and fetal brain tissues; adult PNS-E mice had lower BDNF levels in the amygdala. The gene discussed is BDNF; the disease is Anxiety.