The age of 19 is a period of puberty, when low menstrual flow is related to the hormone levels in the body. When estrogen is low or progesterone is low, it can cause the endometrial lining to grow slower and may even cause a low menstrual flow to occur. Low menstrual flow may also be related to gynecological diseases, such as inflammation of the endometrium or gynecological inflammation, which can cause low menstrual flow. In this case, the hormone panel should be checked on an empty stomach on the second to fifth day of menstruation, if possible, to rule out any abnormalities. If necessary, ultrasound can be done to see the shape of the uterine cavity, and depending on the situation, oral medication can be used to regulate the menstrual cycle.