Sudden bleeding under the body is considered to be related to endocrine disorders, organic diseases, pregnancy-related diseases and external forces. 1. Endocrine disorders: If the patient has a recent high work pressure, often stay up late, or has gynecological endocrine diseases such as polycystic ovary syndrome, premature ovarian failure, etc., due to the endocrine dysfunction, which in turn affects the changes in the body’s sex hormones, resulting in menstrual disorders, irregular bleeding and other clinical manifestations. 2. Organic diseases: for patients with endometrial polyps, cervical polyps, uterine fibroids or malignant tumors, some of them will have symptoms of irregular vaginal bleeding. 3. Pregnancy-related diseases: for pregnant women, if vaginal bleeding occurs, we should be alert to the possibility of pre-eclampsia, induced abortion, ectopic pregnancy. 4. External force: If the patient’s abdomen, pelvis or vulva is subjected to external force, the local blood vessels may be damaged, and bleeding symptoms may occur. For women who suddenly bleed under the body, it is recommended that they go to a regular hospital to improve the sex hormones, gynecological ultrasound and other related examinations, to clarify the cause of the disease and then actively treated under the guidance of the doctor.