abdominal circumference (AC)

Fetal body measurements reflect whether the fetus has grown enough or whether the measurements fall outside the normal range.
The following measurements can usually be made:

During pregnancy many different ultrasounds measurements can be done. They can include the crown rump length (CRL), biparietal diameter (BPD), femur length (FL),
head circumference

One of the most important reasons for prenatal visits and for doing an ultrasound examination is to estimate the fetal size. If the fetus is too small, for example, there may be a problem with the placenta, or with the fetus, and if it's too big, the mother could have gestational diabetes.