The relationship between gallstone formation and pregnancy and the mechanism of occurrence are not clear. The occurrence of gallbladder stones due to pregnancy may be related to hormone levels, bile acid secretion, and decreased biliary smooth muscle tone. Endogenous estrogen secretion increases during pregnancy, inhibiting the absorption of water and sodium by the gallbladder mucosa. Moreover, increased progesterone in the body leads to decreased response of gallbladder smooth muscle to cholecystokinin, decreased contractility and emptying rate of the gallbladder, and increased cholesterol secretion in pregnant women. These factors lead to oversaturation of cholesterol in the bile acid pool, which is conducive to the formation of cholesterol stones. Decreased biliary smooth muscle tone, sphincter of Oddis spasm, cholestasis, increased intrapancreatic duct pressure, and stone obstruction during pregnancy, especially in the second trimester, can induce serious biliary system diseases such as acute cholecystitis, acute cholangitis, and even acute biliary pancreatitis.