Biparietal diameter for fetal weight calculation

Biparietal Diameter Calculation of fetal weight Multiply the biparietal diameter of the fetus by 900 and subtract 5,200 to obtain the weight of the fetus. For example, if the biparietal diameter of the fetus is 7 cm, the weight of the fetus is 1,100 g. However, the calculated value can only be used as an estimate of fetal weight and cannot represent an accurate value.