Blood accumulation in the uterine cavity means that the blood cannot be discharged and accumulates within the uterine cavity. There are many reasons for this, and it is considered to be related to gynecological diseases and obstetric diseases, etc. It is recommended to consult the doctor in time. 1. Gynecological diseases: such as ectopic pregnancy, uterine fibroids, etc., the operation of the uterine cavity is carried out, which will cause some damage to the lining, and it may lead to blood accumulation in the uterine cavity. Some factors may cause adhesions in the uterine cavity, resulting in menstrual blood can not be discharged normally, will accumulate in the uterine cavity, thus causing blood accumulation in the uterine cavity. 2. Obstetric diseases: such as preeclampsia, is a relatively common cause. For example, in the early stages of pregnancy, bleeding caused by the stripping of the egg from the uterine wall is a typical manifestation of preeclampsia. 3. Other factors: if you check the blood in the uterine cavity within two weeks after delivery, it is generally a normal labor and delivery phenomenon, which may be due to the fact that the evil discharge is not clean. If you find blood in the uterine cavity, you should consult a doctor in time to clarify the cause of the disease and give standardized treatment.