There are several reasons for early pregnancy cavity effusion: First, it may be caused by insufficient progesterone level in the body at the beginning of pregnancy or abnormal embryonic development, and the symptoms of cavity effusion, which must be taken seriously, proper rest, preferably without strenuous sports, and less spicy and stimulating food, which can alleviate the problem of cavity effusion. Secondly, the symptoms of effusion may be caused by endometritis. It is recommended to go to the hospital for regular checkups to observe the changes in the effusion. Third, it may be caused by gynecological diseases, such as pelvic inflammatory disease, adnexitis and other diseases, may lead to this situation, it is recommended that women go to the hospital for regular checkups after pregnancy to avoid the impact on the growth and development of the fetus, usually eat more nutritious food, progesterone supplementation in time when progesterone is insufficient.