Aunt refers to menstruation, which is the cyclical shedding of the lining of the uterus in response to cyclical changes in ovarian, hormone levels, which results in bleeding. It is an important physiological phenomenon for women in their reproductive years.
The lining of the uterus undergoes cyclic proliferation stimulated by estrogen, causing the lining to thicken. It is further stimulated by progesterone secreted by the corpus luteum, and the endometrium can grow up to 10mm around the 24th to 28th day of menstruation, and finally the progesterone will withdraw and cause the endometrium to disintegrate, resulting in bleeding, which is called menstruation.
Menstruation is cyclical and self-limiting, with a normal cycle of 21-35 days and an average of 28 days. The normal cycle is 21-35 days, with an average of about 28 days. The duration of each menstrual period is 2-8 days, with an average of 4-6 days. The appearance of regular menstruation is an important sign of the maturity of reproductive function.
A girl’s first menstrual period is called menarche, and the age of menarche is usually between 13 and 14 years old, some may be as early as 11 years old or as late as 16 years old. If a girl does not have her first period after the age of 16, she needs to go to the hospital for a checkup.