The fetal weight is calculated medically by measuring the fetal femur length, biparietal diameter, abdominal circumference and uterine height during an ultrasound examination. This value is only an assessment, not 100% accurate, and has a certain degree of error, and does not represent the actual weight of the fetus at birth. The fetal weight is often calculated in two ways: 1. multiply the uterine height by the abdominal circumference plus 200 cm; 2. multiply 900 by the biparietal diameter minus 5200. generally speaking, a fetal weight of 3000-3500 g is conducive to a normal delivery, but if the fetal weight is too large, it may not be conducive to a normal delivery. Therefore, in addition to regular pregnancy checkups to assess the size of the fetus during pregnancy, you should also exercise properly to reserve your strength for the birth.