PGR and endometriosis: While changes in chromatin accessibility, PR targets and changes in histones and gene expression in eSF decidualization by E2, cAMP and MPA have been shown [9–11], how E2 and P4 individually interact with the endometrial epigenome normally or in inflammatory disorders that compromise endometrial function, e.g., as in the disorder endometriosis, are incompletely understood.