Fetal weight can be calculated by uterine height, abdominal circumference or by ultrasound measurement of fetal biparietal diameter, head circumference, femur length, abdominal circumference and other related data. 1. Calculation through color ultrasound. In the color ultrasound to presume the biparietal diameter, head circumference and so on (1) Weight (g) is equal to 900 x biparietal diameter – 5200. (2) Weight (g) is equal to 1.07 x Biparietal Diameter^3 + 0.3 x Abdominal Circumference^2 x Femur Length (Thigh Bone Length). The fetal weight measured by the above formula is only an estimate. 2. Fetal weight is determined by the doctor’s measurement of uterine height, abdominal circumference, and the amount of amniotic fluid by touching the pregnant woman’s stomach. Fetal weight (g) is equal to uterine height (cm) x abdominal circumference (cm) +/- 200 g. The result may have some error, and the weight is affected by the thickness of the fat in the abdominal wall of the pregnant woman, her own amniotic fluid, and the position of the fetus. Although the first method is relatively accurate, each method is an estimation method and is subject to a certain degree of error, so the assessment also requires the advice of a specialized obstetrician.