The causes of menorrhagia are: 1. the imperfect function of the ovaries during puberty and the unstable level of hormones in the body may cause the problem of menorrhagia, which can be treated without treatment and observed until one year after puberty. 2. the problem of low menstrual flow caused by emotional depression, resulting in the suppression of the endocrine system, which can cause amenorrhea in severe cases. 3. women with severe anemia, the hormone level caused by anemia decreases and the endometrium does not thicken, thus causing the problem of low menstrual flow. 4. The problem of low menstrual flow is caused by the decline in hormone levels caused by anemia and the lack of thickening of the endometrium. 4. It is common to take short-acting or long-acting contraceptive drugs that inhibit the thickening of the endometrium, thus causing a low menstrual flow. 5. Low menstrual flow caused by some surgeries is common after a hysterectomy, where the uterus is cleared, so there is a problem of low menstrual flow. 6. A congenital infantile uterus can also cause a problem of low menstrual flow.