If a woman is having a menstrual period due to partial adhesions of the cervical canal, the menstrual blood cannot be discharged from the uterine cavity immediately, and the menstrual blood may pool inside the uterus and appear as a blood clot in the uterine cavity. If the menstrual blood only temporarily accumulates in the uterus, there is no special danger. If the clot accumulates for too long, the most common danger is that it will cause continuous swelling and pain in the lower abdomen, and may even stimulate the uterus and lead to adhesions in the uterine cavity, which may significantly reduce the amount of menstruation after the next menstruation. For women who have blood clots accumulating in the uterine cavity after abortion, the greatest danger is infection, which may cause endometrial inflammation and may lead to localized mechanization of the uterine cavity or even cause coagulation dysfunction.