ABSTRACT
The human endometrium is a highly dynamic tissue that undergoes approximately 400 menstrual cycles during a woman's lifetime (1). During each menstrual cycle, the ovaries produce estradiol (E2) and progesterone, which induce structural and functional changes within the endometrium in anticipation of embryo implantation and the establishment of a pregnancy (2). The human menstrual cycle is divided into two phases: the proliferative phase, which follows menstruation and precedes ovulation, and the secretory phase, which occurs postovulation (3). During every menstrual cycle, the uterus is remodeled to become receptive for potential embryo implantation during the secretory phase.
