What are the cyclical changes of the endometrium?

For women who want to get pregnant, they should not only pay attention to their ovulation period, but also have a certain understanding of whether the thickness of their endometrium is normal. Especially women who have experienced miscarriage should pay attention to whether the thickness of their endometrium is normal. However, many women do not understand the cyclical changes of the endometrium very well, which is not good for preparing for pregnancy. Therefore, this article will introduce to you the cyclical changes of the endometrium.

Proliferative phase: After menstruation, under the action of estrogen, epithelial cells begin to proliferate from the broken ends of the endometrial glands and cover the surface of the uterine mucosa upwards. Around the 5th to 9th day of the menstrual cycle, the endometrium is very thin, the glands are scattered and sparse, the glandular ducts are narrow and straight, and the glandular cavity surface is flat. During the 10th to 14th day of the menstrual cycle, the endometrium thickens into a wavy shape, the glands and interstitium proliferate significantly, the glands increase in number, become wider, and gradually bend. The blood vessels also proliferate and gradually become spiral. The interstitium is dense and proliferative. This period corresponds to the stage of follicular development and maturation, which is around the 5th to 14th day of the menstrual cycle.

Secretory phase: It is approximately 15 to 23 days of the menstrual cycle, which is equivalent to the luteal maturation stage after ovulation. The progesterone and estrogen secreted by the corpus luteum will cause the endometrium to continue to thicken during the proliferative phase, and the glands will further expand, bend, and secrete. The blood vessels also grow rapidly and become more tortuous. The interstitium becomes loose and edematous. At this time, the endometrium is thick and soft, containing rich nutrients, which is conducive to the implantation and development of the fertilized egg.

Premenstrual period: Equivalent to the corpus luteum regression stage, approximately 24 to 28 days of the menstrual period. When the corpus luteum degenerates, the levels of progesterone and estrogen gradually decrease. This decrease in hormones will cause the intimal interstitial edema to subside and become dense, resulting in compression of blood vessels and blood stasis. Finally, local blood vessels will experience spasmodic contraction in turn, causing intimal ischemia, necrosis, and vascular rupture and bleeding.

Menstrual period: Day 1 to 4 of the menstrual cycle. In the functional layer of the endometrium (the part above the basal layer, about 5 to 6 mm thick), scattered small hematomas will cause the necrotic endometrium to peel off and be discharged with the blood, which is called menstruation. The basal layer of the endometrium then begins to proliferate and form a new endometrium. Therefore, the menstrual period is actually the end of one cycle and the beginning of the next cycle.

After understanding the cyclical changes of the endometrium, I would like to remind all female friends that having sexual intercourse during menstruation can easily lead to endometrial hyperplasia. Sometimes the hyperplasia is physiological, but sometimes it is pathological. Pathological endometrial hyperplasia must be treated actively, otherwise it will have a greater impact on future fertility.