A small amount of fluid in the uterine cavity needs to be clearly identified and treated, and it needs to be treated with fertility preservation when it is caused by pre-eclampsia, medication when it is caused by gynecological inflammation, and surgery when it is caused by gynecological tumor. 1. Pre-eclampsia: small amount of vaginal bleeding accompanied by paroxysmal abdominal pain at the beginning of pregnancy, a small amount of fluid in the uterine cavity by ultrasonography, combined with progesterone and blood HCG (human chorionic gonadotropin) test, need to pay attention to rest, and follow the doctor’s instructions to give progesterone and other drugs to protect the fetus treatment. 2. Gynecological inflammation: such as pelvic inflammatory disease, due to inflammatory stimulation can also cause a small amount of fluid in the uterine cavity, may also be accompanied by lower abdominal pain and increased vaginal discharge and other symptoms, combined with the history and clinical manifestations, signs and so on, can be a clear diagnosis, and need to be actively given an effective antibiotic treatment, such as ceftriaxone, metronidazole and so on. 3. Gynecological tumor: such as endometrial cancer, etc., can also cause small amount of fluid in the uterine cavity, which is often accompanied by irregular vaginal bleeding and discharge of foul-smelling vaginal fluid, so it is necessary to carry out diagnostic curettage and pathological examination according to doctor’s instruction, and if necessary, it is necessary to give surgical treatment and auxiliary radiotherapy and chemotherapy. When the ultrasound examination suggests a small amount of fluid in the uterine cavity, it is recommended to go to the hospital in time for examination, to clarify the cause of the disease, and then follow the doctor’s instructions for active treatment.