There are many causes of black blood clots in the lower body during non-menstrual periods, mainly including physiological causes as well as pathological causes, such as abnormal pregnancy, functional uterine bleeding, uterine fibroids, endometrial thickening, endometrial cancer, etc. It is recommended to go to the hospital for examination and treatment of the cause. Physiological causes are usually seen in ovulatory bleeding, which is the middle of two regular menstrual periods. Due to a brief drop in estrogen level caused by ovulation, the endometrium of some women lose estrogen support and endometrial shedding occurs, causing regular vaginal bleeding and symptoms of black blood clots in the lower body during non-menstrual periods, most of which can stop on their own in 2-3 days and can be observed without treatment. For women with persistent ovulatory bleeding, they need to be treated with oral medication together with acupuncture in Chinese medicine after excluding other diseases. Pathological causes 1. Abnormal pregnancy: The above symptoms can occur when a woman has ectopic pregnancy or pre-eclampsia, which requires timely medical attention. If the pregnancy is ectopic, surgery is usually required; if it is pre-eclampsia, progesterone can be supplemented to maintain the pregnancy; 2. Functional uterine bleeding: endocrine disorders lead to endocrine disorders, manifesting as menstrual cycle disorders, irregularity, symptoms of black blood clots from the lower body during non-menstrual periods, such as long-term irregular menstruation and large menstrual volume, which may cause anemia and should be treated at the hospital in time, such as oral progestin and hemostatic drugs; 3. Fibroids: typical symptoms of fibroids include irregular vaginal bleeding during non-menstrual period, increased menstrual flow, dysmenorrhea, etc. Asymptomatic people usually do not need treatment and regular review is recommended. It can be treated by medication, such as oral progesterone, or surgery; 5.Endometrial cancer: endometrial cancer mainly manifests as abnormal vaginal bleeding, and the enlarged uterus in the abdomen can be palpated in advanced stage. At present, the treatment is mainly surgical, such as radical hysterectomy plus bilateral tubal and ovarian resection, and postoperative adjuvant radiotherapy to improve the patient’s survival quality. In addition, diseases such as polycystic ovary syndrome, hyperprolactinemia, cervical lesions and ovarian endocrine dysfunction can also present with symptoms of black blood clots in the lower body during non-menstrual periods, which should be seen in a timely manner to clarify the cause and treat the cause so as not to delay the condition.