The formation process of menstruation mainly occurs when a female reaches puberty and her ovaries have developed fully, beginning to secrete some progesterone and estrogen. Under the influence of these hormones, some periodic changes will occur. When the hormone levels decrease, the endometrium will experience withdrawal bleeding, which is menstruation.
1. During the menstrual cycle, the ovarian follicle goes through a series of stages: primary follicle, sinus follicle, pre-ovulatory follicle, and mature follicle. As the follicle gradually enlarges, the secretion of estrogen and progesterone by the ovaries also changes continuously. Due to the changes in estrogen and progesterone, the endometrium undergoes three stages of alteration: proliferative phase, secretory phase, and menstrual phase.
2. The proliferative phase occurs from the 5th to the 14th day of the menstrual cycle, during which the endometrium reaches a thickness of approximately 3 to 5 millimeters. The secretory phase occurs from the 15th to the 28th day of the menstrual cycle, and the endometrium reaches a thickness of approximately 10 millimeters at this time. Menstruation occurs when the endometrium loses the support of estrogen and progesterone and undergoes periodic shedding.
3. Menstruation is a physiological cycle in women that is caused by the periodic secretion of estrogen and progesterone from the ovaries and the periodic shedding of the endometrium. It is a normal physiological phenomenon. The normal menstrual cycle for women ranges from 21 to 35 days, with a menstrual period lasting generally from 3 to 7 days. The normal range for menstrual blood volume is between 20ml and 80ml. Menstruation occurring one week earlier or later than usual is also considered within the normal range.
