Low menstrual flow is related to the ovaries. Menstruation occurs when the endometrium sheds its blood, and the endometrium is thickened by estrogen. If the ovaries do not ovulate or the follicles are not well developed, the amount of estrogen secreted will be less, and the endometrium will be thinner, so when you have your period, you will have less bleeding. If there is normal ovulation, the level of estrogen is relatively high, the endometrium will thicken under the action of estrogen, and when it comes to menstruation, estrogen and progesterone will retreat bleeding, so, the bleeding will be more. If there is little menstruation, you need to go to the hospital to check whether there is ovulation, and check the sex hormone six and thyroid hormone to see whether it is caused by endocrine disorders.