These secrete for only a very short time unless pregnancy or pseudopregnancy intervene. Small and anaemic, low motility, lumen small and slit-like. Epithelium thin, mitotic figures infrequent. Leucocytes abundant in stroma, migrate through the epithelium into vaginal lumen. Stringy mucous in which are entangled many leucocytes and a few nucleated epithelial cells.
Some follicles grow rapidly.
Become more vascular, water content increases, organ distends. Contractility more pronounced. Leucocytes disappear from mucosa. Endometrial glands hypertrophy. Epithelum thickens, numerous mitoses in inner layers.