To identify differential distributions of KEGG pathways, we performed a FatiGO+ analysis with the two lists of genes up-regulated gene during endometrial receptivity of the natural and stimulated cycles. There were numerous differences, between the natural and stimulated cycles, in main systems involved in the implantation process, such as the TGFβ signaling pathway, the complement and coagulation cascades, and leukocyte transendothelial migration. Red, genes up-regulated in natural cycles; pink, genes up-regulated in stimulated cycles.