People with uterine fluid can lie flat or on their side, and there is no special need for posture. There are many causes of fluid in the uterus and patients should actively investigate them. Usually, lying flat or on the side is not directly related to fluid in the uterine cavity and will not cause adverse effects on the condition. Therefore, people with fluid in the uterine cavity can lie flat or on the side, depending on their own comfort level. Some people may have a small amount of fluid in the uterine cavity, which is physiologic, and there is no need to take treatment measures or worry excessively. At the same time, malformation of the reproductive tract, endometrial tuberculosis, cervical cancer, uterine adhesions, endometrial polyps, uterine submucosal leiomyoma and other diseases can also cause uterine fluid, but it is a pathological uterine fluid. Pathological uterine effusion is often accompanied by vulvar itching and menstrual disorders, which affects the quality of life and health. It is recommended that people with uterine fluid undergo further detailed examination, and if it is clear that it is caused by a disease, they should actively cooperate with doctors to take treatment measures.