As the Sankey plots demonstrated, in the second trimester, Megamonas was negatively correlated with FT4 and further negatively correlated with GA, and Blautia was positively correlated with Hb and further negatively correlated with GA, indicating that gut microbiota could be involved in occurrence of anemia by interacting with clinical indices (Figure 5D). Here, GSTM1 is linked to anemia (phenotype).