The size of the belly of a woman pregnant with twins depends on a number of factors such as the month of pregnancy, the pregnant woman’s own pre-pregnancy weight and so on, and there is no exact one specific value. Generally speaking, a woman’s stomach will not increase significantly in the first trimester of pregnancy because the fetus is still in the embryonic state at this time. As the months of pregnancy increase and the fetus gradually develops, the pregnant woman’s stomach will also slowly increase in size, usually around four months can be seen in the belly bulge. The size of the belly is related to the number of fetuses, the development of the fetuses, and the nutritional status of the pregnant woman’s diet. The belly of a woman pregnant with twins will be slightly larger than that of a single pregnancy, and the risk of a twin pregnancy is higher than that of a single pregnancy. Pregnancy will increase the burden of various organs and tissues of the pregnant woman herself, therefore, pregnant women should undergo regular medical checkups, and in addition to checking the abdominal circumference, they should also check the fetal movement, fetal heartbeat, fetal position, etc., and at the same time, test the pregnant woman’s own blood pressure, blood glucose, liver, kidneys, and cardiac function. When pregnant with twins, pregnant women should pay attention to their diet, pay attention to their work and rest, have regular checkups, and seek immediate medical attention if they feel unwell to avoid accidents such as miscarriages and premature births.