Fetal weight estimation generally relies on ultrasound measurement and uterine height-abdominal circumference calculation. 1. Ultrasound measurement: The fetal weight is inferred by measuring the biparietal diameter, head circumference, abdominal circumference, humerus length and femur length in the ultrasound. For example, fetal weight (grams) = 900 * BPD (Biparietal Diameter) – 5200, or = 1.07 * BDP * BDP * BDP + 0.3 * AC * AC * FL, there is a certain degree of error between the actual weight at birth and the predicted weight. 2. Uterine height-abdominal circumference method: Obstetricians measure the uterine height and abdominal circumference of pregnant women, and estimate them by virtue of the obstetrician’s experience. The commonly used formula is fetal weight (g) = uterine height (cm) × abdominal circumference (cm) + 200, and this calculation is applicable to pregnant women in full-term labor. Estimation of fetal weight during pregnancy is subject to a certain degree of error, and pregnant women are advised to decide on the mode of delivery after a comprehensive assessment by an obstetrician in the late stages of pregnancy.