These changes occurring during the endometrial cycle, give the endometrium different hysteroscopic patterns typical of each phase, allowing the assessment of normal “hysteroscopic” endometrial cycle.
1- Proliferative phase: the endometrium has a light pink color due to the presence of small vessels. The surface is smooth and glands are small and rounded, appearing as small and uniform dots. The endometrial notch is small and generally hemorrhagic.
2- Secretory phase: The endometrium has a pale pink color. The surface is slightly wavy and irregular. The glands are larger, open and rose at the level of the superficial layer. The vessels disappear from the endometrial surface due to stromal edema. The endometrium reaches its maximum thickness at this stage, showing a deep avascular endometrial notch.
3- Menstrual phase: the endometrium takes on a reddish color, with indentations and bleeding. In this phase there are alternating areas of detaching and well preserved endometrium.