Uterine fluid during pregnancy may discharge a brownish colored discharge, but there are individual variations. The presence of fluid in the uterine cavity in early pregnancy may be caused by coitus, external stimuli or luteal insufficiency, and a small amount of brown vaginal discharge may occur. When this phenomenon occurs, it is necessary to consult a doctor in time for fertility preservation treatment. Fluid in the uterine cavity in the middle and late stages of pregnancy may be caused by placenta praevia, placental abruption, etc., and a small amount of brown vaginal discharge may also occur. Both of these conditions are dangerous and require prompt medical attention. During pregnancy, you must pay attention to proper rest, avoid strenuous exercise and exertion, reasonably increase the diet and nutrition, and prohibit coitus in the first three months of pregnancy. When the presence of fluid in the uterus needs to be actively treated.