For fetal abdominal anechoia shown by ultrasound, first of all, we should look at the specific parts of the anechoia, fetal abdomen including upper abdomen and lower abdomen, the specific reasons are as follows: 1. upper abdomen anechoia can originate from the liver, such as liver cysts and the more common choledochal cysts in fetal period, cysts in the kidney also show anechoia; 2. lower abdomen anechoia may be mesenteric cysts, intestinal duplication malformation, etc., intestinal duplication malformation can be manifested as curvilinear anechoic. For girls, cystic anechoic lower abdomen may originate from the ovaries, such as simple cysts of the ovaries. Therefore, it is important to analyze the origin of the cystic dark areas according to the different anatomical sites before making a more accurate judgment and analysis. For ovarian cysts in the lower abdomen, they are sometimes not easily distinguished from cysts of the mesentery, and if they are cysts of the mesentery or intestinal duplication malformations, it is recommended to review them after the birth of the fetus.