The abdominal circumference of pregnant women will grow with their weight and the growth and development of the fetus, which can be measured from about 16 weeks of pregnancy onwards. It will increase or decrease within the range of about 8mm per week. The fetus grows faster when the pregnant woman is around 20-24 weeks pregnant, and the abdominal circumference grows significantly during this time, after the pregnant woman is 34 weeks pregnant the fetus grows slowly, and the abdominal circumference grows gradually, but the growth rate is not too obvious. Pregnant women need to do regular pregnancy checkups, and abdominal circumference is one of the checkup items.