Fig. 4

Visualization by principal coordinate analysis (PCoA) shows clustering of the amniotic fluid extracellular vesicles (AM EVs) and maternal fecal extracellular vesicles (FE EVs). Alpha diversity was quantified with the Shannon index and the number of observed features and beta diversity with PCoA using the Bray–Curtis dissimilarity in each sample group (AM = amniotic fluid, AM EVs = amniotic fluid-derived extracellular vesicles, FE = maternal feces, FE EVs = maternal feces-derived extracellular vesicles). The statistical significances of differences between the sample groups were estimated for alpha diversity with the Kruskal–Wallis H, as implemented in QIIME2. PERMANOVA was used as the statistical test for differences between the groups, as quantified by the Bray–Curtis dissimilarity. P < 0.05 was considered statistically significant