Figure 3. Endometrial cycle dating based on Noyes et al. (1950) criteria (200x): (A) Day 17: “piano key” appearance of glandular epithelium with vacuoles at nuclei level; (B) Day 18: luminal vacuoles with smaller size and the nuclei approaching the base of the glandular cell; (C) Day 19: presence of intraluminal secretion with few vacuoles on cellular cytoplasm, absence of mitosis and pseudo stratification; (D) Day 20: the peak of intraluminal secretion with stromal edema onset, presence of rare vacuoles and round nuclei located at the base of the glandular cell.; (E) Day 23: presence of prominent spiral arterioles with thickened walls, coiling and endothelial proliferation; (F) stromal-glandular dissociation - gland on day 17 with decidualized stroma.