Uterine fluid does not necessarily have an effect on the fetus. Whether fluid in the uterine cavity has an effect on the fetus depends on the nature of the fluid, as it can be physiological or pathological. For most women, there is more or less fluid in the uterine cavity, but most of them are physiological and most of them will disappear on their own. If the pregnancy tests do not indicate any abnormality and the pregnant woman has no vaginal bleeding or abdominal pain, it usually will not affect the fetus. However, some women have fluid in the uterus caused by pathological inflammation, such as pelvic inflammatory disease. If a pregnant woman has pain in the abdomen or vaginal bleeding, there is a possibility of pre-eclampsia, and she needs to seek medical attention in time. Pregnant women with fluid in the uterus should seek medical attention and examination in a timely manner, take bed rest according to the doctor’s recommendation and have an ultrasound examination to check the development of the fetus in about 10 days.