The belly is already bulging at 21 weeks of pregnancy, the uterine height range is about 17~21.5cm, and the abdominal circumference is 80~90cm, but there are individual differences in the exact size of the belly. 21 weeks pregnant belongs to the mid-pregnancy, this stage of fetal development is relatively fast, the uterus gradually increased, the normal uterus in the flat umbilical position, the uterus height of 17~21.5cm or so, abdominal circumference of 80~90cm or so. However, pregnant women with different body types, fetal development is not the same, the size of the stomach there are individual differences, such as pregnant women with a thin body type or fetal development is slightly smaller, the stomach may be smaller. If the pregnant woman’s body type is fat, more fat on the stomach or the development of the fetus is large, the stomach will be larger. In addition, if you are pregnant with multiple fetuses, your belly will be significantly larger than if you are pregnant with singletons. There are individual differences in how big the belly is at 21 weeks pregnant. It is recommended to take a good pregnancy test as long as the development of the fetus is in line with the normal gestational weeks.