Low menstrual volume is a kind of menstrual irregularity. There are two causes of menstrual irregularity, namely structural and non-structural. Structural i.e. abnormal uterine structure causes irregular menstruation, including endometrial polyps, fibroids, adenomyosis, endometrial precancerous lesions or endometrial cancer, which are structural changes. There are also adhesions in the uterine cavity and changes in the morphology of the uterine cavity, which can also cause menstrual irregularities. Non-structural causes of menstrual disorders, such as gynecological endocrine diseases that cause anovulation or abnormal ovulation, can cause menstrual disorders, including polycystic ovary syndrome, hyperprolactinemia, abnormal thyroid function, or decreased ovarian function can also cause menstrual disorders. In addition, there are also medical causes, i.e. when a woman takes hormone supplementation drugs or birth control pills, it can lead to low menstrual flow or irregular menstruation. Abnormal bleeding caused by an uterine operation in the hospital can also cause patients to think that their periods are irregular. Some hematologic disorders are also non-structural changes that can also cause menstrual disorders but with heavy menstrual flow.