What is a period?

Menstruation refers to menstrual cycle, which refers to regular periodic uterine bleeding, which is one of the external signs of reproductive maturity. This bleeding is the result of ovarian follicle maturation, ovulation and corpus luteum formation, and changes in the endometrium from the proliferative phase to the secretory phase. Under normal circumstances, the vast majority of menstrual cycles are 28-30 days. If 3 days in advance or 3 days later, are normal phenomena. The general menstruation will be clean in 3-7 days, most of them will be clean in 3-5 days, and the menstrual volume is generally between 38-55ml, which is a normal phenomenon.