There are some individualized differences in the size of each fetus, usually at 17 weeks of gestation the weight of the fetus is about 110g-150g, the biparietal diameter of the fetus is about 3.9cm-4.3cm, the length of the femur is about 2.5cm-3.0cm, and the length of the vertex and hip is about 12.8cm. Each fetus grows and develops differently, so there are individualized differences in the size of each fetus, and it is usually normal to have a small error. At 17 weeks of gestation, the fetus has already shown respiratory movements, the scalp has already grown hair, there is no subcutaneous fat, the skin is thin and dark red, some women in labor can feel the movement of the fetus, but at this time the movement of the fetus is relatively weak. Seventeen weeks of pregnancy belongs to the early stages of pregnancy, at this time the fetus’s organs begin to develop, pregnant women should pay attention to the nutritional mix of comprehensive and balanced diet, in order to ensure the normal growth and development of the fetus.