Menstruation is the regular, cyclic uterine bleeding that should be accompanied by follicle maturation, egg discharge and corpus luteum formation in the ovaries, and changes in the endometrium from hyperplasia to secretion. It is regulated by the female hormones secreted by the cerebral cortex, hypothalamus, pituitary gland and ovaries. Having a normal menstrual cycle indicates that there is no problem with these systems. There are two types of menstrual periods, those with ovulation and those without ovulation. Therefore, only ovulated menstruation has the ability to conceive. We know that after a woman reaches puberty, under the interaction of the hypothalamus, pituitary gland, and ovaries, the eggs in the ovaries gradually develop, mature, ovulate, and secrete female hormones, which give cyclical effects on the uterus and other reproductive tracts. Under this influence, the endometrium undergoes a series of changes, namely endometrial thickening, vascularization, glandular secretion, vascular rupture and bleeding, and endometrial shedding, which eventually manifests as periodic vaginal bleeding, which is called menstruation. If the ovum is united with the sperm in the middle of the menstrual period, the fertilized egg runs to the uterine cavity at a time when the endometrium is thickened and rich in blood vessels and nutrients, which is conducive to implantation of the pregnant egg. If there is no fertilization, then the endometrium is due to shed and the menstrual cycle begins again, which means that some infertile women have menstruation but do not ovulate, either because the egg itself has degenerated before reaching maturity or because it is mature but cannot be expelled from the ovary. However, the endometrium can still shed and bleed under hormonal influence, but cannot conceive. However, the endometrium can still shed and bleed under the influence of hormones, but cannot conceive.