A bulging belly in the morning of the third trimester of pregnancy that gets smaller when you go to the bathroom may be due to the uterus getting bigger, which in turn squeezes the bladder. In the third month of pregnancy, the fetus baby is about seven or eight centimeters long and about the size of an egg, although it is not possible to tell from the size of the pregnant woman that she is pregnant. However, the gradually growing uterus will still press on the bladder in front of the uterus, so in the morning when the bladder is full, the belly will be slightly bulging, and after going to the toilet the bladder will become smaller, the belly will return to its original position, and the bulge will disappear. So this is a normal physiological situation, do not need to worry too much, during pregnancy need to pay attention to rest, ensure adequate nutritional supplements, maintain a happy mood and physical health, to ensure the healthy growth of the fetus.