Taking progesterone to have less menstruation may be caused by drug effects, or it may be related to physiological or pathological factors such as endocrine disorders, endometrial abnormalities, uterine adhesions, polycystic ovary syndrome, thyroid disorders and so on. 1. Drug factors: progesterone is a kind of progesterone, which promotes the transformation of endometrium from proliferative phase to secretory phase, and may cause menstrual decrease after taking it. 2. Physiological factors: such as cold during menstruation or excessive menstrual flow during the last menstrual period can also cause physiological menstrual flow reduction, which is a normal phenomenon. 3. Pathological factors (1) Endocrine disorders: such as nervousness, anxiety, persistent thinness, late night, overwork, etc. can cause endocrine disorders, manifested in menstrual abnormalities such as low menstrual flow and amenorrhea. (2) Endometrial abnormality: such as endometrial tuberculosis, chronic endometritis, endometrial injury, etc. can cause symptoms of decreased menstrual flow. (3) Uterine adhesion: such as surgery in the uterine cavity, etc. can cause endometrial infection and injury, thus causing uterine adhesion, which can manifest as symptoms of decreased menstrual flow or even amenorrhea. (4) Polycystic ovary syndrome: with persistent absent or sparse ovulation and high androgen as the main clinical manifestations, it can cause symptoms such as sparse menstruation, reduced menstrual flow and even amenorrhea. (5) Abnormal thyroid function: For example, in patients with severe hyperthyroidism, the process of thyroid hormone secretion, release and metabolism is inhibited, which can cause symptoms such as reduced menstrual flow. It is recommended to go to the hospital in time to find out the cause of low menstrual flow and then actively treat it, so as not to delay the condition.