Measurement of fetal abdominal diameters

Axial image of the fetal abdomen of a late second-trimester fetus. This measurement is taken at the level of the fetal stomach, liver, and umbilical vein. Calipers are used to measure the diameters of the fetal abdomen. These measurements can be averaged, or an abdominal circumference can be calculated. These measurements are used to assess gestational age and especially fetal weight.