The endometrium goes through cyclical changes under the influence of hormones, and immune effectors in the endometrium change their populations cyclically as well. Dynamic changes in immune effectors determine endometrial cytokine and chemokine milieus and, consequently, the endometrial immune response. Endometrial immune responses have been shown to be important for trophoblast invasion and early pregnancy. Indeed, dysregulated endometrial inflammatory immune responses are associated with reproductive failures, such as recurrent pregnancy losses, repeated implantation failure, and gynecological diseases with oncogenic potential. Hence, the investigation of endometrial gene expression may predict infertility, gynecological and oncological conditions.