Fluid accumulation in pregnancy may be a normal physiological phenomenon, or it may be caused by ectopic pregnancy, preeclampsia, inflammation and other reasons. 1. Normal physiological phenomenon: clinically pelvic fluid less than 10 cm is called normal phenomenon, because normal women are fluid in the body, as long as the development of the gestational sac is very normal other aspects of this fluid without discomfort does not need to intervene. 2. Ectopic pregnancy: If the amount of fluid in the pelvic cavity in early pregnancy is relatively large, and accompanied by more obvious symptoms of abdominal pain, as well as irregular vaginal bleeding phenomenon, it is considered to be the rupture of ectopic pregnancy. 3. Pre-eclampsia: early pregnancy because of low progesterone, there may be intrauterine blood pre-eclampsia, so ultrasound can be seen in the uterine cavity with fluid. 4. Inflammation: If the body resistance is poor after pregnancy, there will be inflammatory exudate when suffering from pelvic inflammatory disease, so there will be pelvic fluid. It is recommended that patients with effusion in pregnancy should go to the hospital in time to do the relevant examination, to clarify the cause of the disease under the guidance of the doctor reasonable treatment.