There are many reasons why the menstrual volume slowly becomes less: First, if the endocrine disorders such as ovarian hypofunction, thyroid function abnormalities, polycystic ovary syndrome, etc. may affect ovulation and lead to reduced menstrual volume, which is usually diagnosed by ultrasound examination and blood sampling and laboratory tests combining endocrine 6 items and thyroid function. Second, if strenuous exercise or dieting, oral weight loss drugs may also affect the amount of menstruation, resulting in reduced menstruation, or even amenorrhea. If a woman has had multiple scrapings or abortions, it may damage the basal layer of the uterus and cause adhesions in the uterine cavity, making the menstrual flow less and less. Fourth, if there is some endometritis or previous pelvic tuberculosis, or even endometrial tuberculosis, which destroys the endometrium, it will also lead to reduced menstruation. V. If you take drugs that affect your menstruation, such as antidepressants, it can lead to a decrease in menstrual flow.