Functional uterine bleeding is also known as dysfunctional uterine bleeding, and its common causes include ovulation disorder-related abnormal uterine bleeding, luteal insufficiency, and endometrial abnormality. 1. Abnormal uterine bleeding associated with ovulatory disorders: for example, puberty with imperfect development of the hypothalamic-pituitary-ovarian axis and the menopausal transition period with no cyclic ovulation due to the decline of ovarian function can lead to hormone secretion abnormalities, endometrial hyperplasia and shedding abnormalities, which in turn lead to the phenomenon of abnormal bleeding. 2. Insufficient luteal function: in luteal atrophy and luteal insufficiency, the process of luteal atrophy will prolong the shedding of the endometrium and the menstrual cycle will be longer; in the latter case, due to insufficient secretion of progesterone during the luteal phase, the luteal phase will be shortened, which will be manifested as a shortened cycle with a slight increase in the amount of menstruation, and so on. 3. Endometrial abnormality: often due to endometrial fibrinolytic enzyme activity and prostaglandins and other vasodilatory factor secretion dysregulation, resulting in abnormal bleeding phenomenon. If you have functional uterine bleeding, you should consult a doctor in time and follow the doctor’s instructions to avoid aggravation of the condition.