Patients with blood clots during menstruation may have physiological or pathological reasons, as follows: 1. Physiological reasons: mainly due to less activity during menstruation, prolonged sitting or lying down, resulting in the accumulation of blood clots in the uterine cavity for too long, which is a physiological manifestation and generally does not require treatment. 2. Pathological reasons: suffering from endometrial polyps, uterine Myoma or adenomyosis and other diseases, resulting in a relatively large amount of menstruation, will also appear clots during menstruation. In this case, further pelvic ultrasound examination is needed to clarify the diagnosis, and if it is caused by organic lesions, surgery is needed for treatment.