The formula for estimating fetal weight can be calculated from the uterine height and abdominal circumference, or by ultrasound examination of fetal head circumference, biparietal diameter, femur length, etc. The formula for estimating fetal weight can be calculated from the uterine height and abdominal circumference. The formula for calculating from uterine height and abdominal circumference is fetal weight (g) = uterine height*abdominal circumference (cm) ± 200. The weight calculated by this method has a larger error, and some pregnant women who have thicker subcutaneous fat may calculate a heavier fetal weight. There are also several formulas for calculating the value by ultrasound examination. Fetal weight (g) = 4973.72 – 260.69 * head circumference (cm). Fetal weight (g) = 900* Biparietal diameter (cm) – 5200. Fetal weight (g) = 2232.56 – 747.42* Femur length (cm). The estimated fetal weight is only an estimate, an assessment of fetal development and the conditions under which the mother will give birth, and is not the actual weight of the fetus after birth.