Uterus: phases of the menstrual cycle
The four phases of the menstrual cycle are shown here at the same magnification to demonstrate both glandular changes and variation in thickness of the endometrium during the menstrual cycle. 10x
Proliferative phase >
The proliferative phase (days 6-14) shows straight glands with no secretory product in the lumens, no evidence of spiral arteries, and a relatively thin endometrium.
Secretory phase >
Endometrium in the secretory phase (days 15-25) reaches maximal thickness. Spiral arteries are readily identifiable; glands become secretory. Predecidual cells appear around day 24.
Pre-menstrual phase >
During the pre-menstrual phase (ischemic portion of the secretory phase, days 26-28), the endometrium shrinks and necrotic tissue is obvious. Other characteristics of the secretory phase continue.
Menstrual phase >
The menstrual phase (days 1-5) demonstrates sloughing of the functional zone until only the basal zone remains.
The uterine lumen is visible at the top of each section.