Scanning electron micrographs of 3 biopsies from the same patient (no. 5) demonstrates the variable response of the epithelium to exogenous hormone supplementation. (A) suboptimal epithelial appearance for D5 natural cycle displaying variable morphology of flattened, pleiomorphic cells without cell borders, variable microvilli coverage and structure and few cilia groups. (B) D5 of the short E2 cycle shows an abundance of fully developed uterodomes, (C) D7 of long E2 cycle shows developing uterodomes. Scale bar = 10 μm.