Uterine fluid is usually less than 10mm as normal physiologic uterine fluid. Uterine fluid generally refers to the accumulation of blood, pus and other fluids in the uterine cavity. Physiologic uterine fluid is generally less than 10mm, and usually does not cause significant discomfort. It may be caused by follicular development, the gradual rise in estrogen levels, and the increase in vascular epithelial growth factor that makes the uterine secretions viscous and clogs the cervical canal, leading to poor discharge of secretions. Uterine fluid may also be caused by chronic pelvic inflammatory disease, implantation of birth control devices, uterine infections, uterine pathology, congenital malformation of the reproductive tract, etc., which may be accompanied by symptoms such as lower abdominal pain, lower abdominal distension, and increased vaginal discharge. After the presence of uterine fluid in the clinic, it is recommended to identify the cause of the disease under the guidance of a physician and then carry out the relevant treatment.