Menstrual health knowledge, the occurrence of menstruation

Menstrual health knowledge, the occurrence of menstruation:

Cyclic changes in the endometrium

- Under the action of estrogen and progesterone secreted by the ovaries, the female endometrium will undergo cyclical proliferation, secretion and shedding. In the first half of each menstrual cycle, the follicles in the ovaries begin to develop and secrete estrogen, which promotes the proliferation and thickening of the endometrium to prepare for the implantation of the fertilized egg.

Ovulation and corpus luteum formation

- Around the 14th day of the menstrual cycle, the mature follicle ruptures and discharges the egg, a process called ovulation. After ovulation, the follicle wall collapses to form a corpus luteum, which begins to secrete progesterone and estrogen, causing the endometrium to further thicken on the basis of the action of estrogen, and become more loose and rich in nutrients, creating better conditions for the implantation of the fertilized egg.

Changes in hormone levels

- If the egg is not fertilized, the corpus luteum begins to degenerate 9 to 10 days after ovulation, and the secretion of estrogen and progesterone decreases rapidly. The endometrium begins to become ischemic and necrotic due to the loss of support from these two hormones, and then falls off. The fallen endometrial fragments flow out of the vagina along with the blood, forming menstruation.

Neuroendocrine regulation

- The regulation of the menstrual cycle is a very complex process, mainly involving the neuroendocrine regulation of the hypothalamus-pituitary-ovarian axis. The hypothalamus secretes gonadotropin-releasing hormone, which stimulates the pituitary gland to secrete follicle-stimulating hormone and luteinizing hormone. These two hormones act on the ovaries to promote follicle development, ovulation and corpus luteum formation. At the same time, the estrogen and progesterone secreted by the ovaries will feedback regulate the hypothalamus and pituitary gland, so that the hormone levels remain relatively stable, thereby maintaining a normal menstrual cycle.