The presence of fluid in the uterine cavity in mid-pregnancy may be a sign of miscarriage, and in most cases, birth control is required. Fluid accumulation in the uterine cavity in mid-pregnancy mostly indicates the presence of blood in the uterine cavity, which is a sign of pre-miscarriage, and the pregnant woman may also have symptoms such as abdominal pain and vaginal bleeding, which can induce an infection in the uterine cavity. If the effusion is large, fertility preservation treatment is usually needed. If the fetus develops well, the amount of fluid is not large, and there are no other symptoms, you may not need birth control, and regular ultrasound checkups are sufficient. Pregnant women should pay attention to bed rest in their daily life, avoid exertion and staying up late, keep a happy mood, do not have too much pressure, under the guidance of the doctor’s treatment, and regular review.