Fetal abdominal circumference
Abdominal circumference (AC) is one of the basic biometric parameters used to assess fetal size. AC together with biparietal diameter, head circumference, and femur length are computed to produce an estimate of fetal weight. In the second trimester this may be extrapolated to an estimate of gestational age and an estimated date of delivery (EDD).
Sonographic technique
Transverse section through the upper abdomen, which should demonstrate the following fetal landmarks:
- fetal stomach
- umbilical vein
- portal sinus
AC measurement should not be taken on a foreshortened abdomen and the calipers should be on the skin surface (skin surface should be visible).
The kidneys and cord insertion should not be visible. The umbilical vein should not be seen up to the skin line.
The gallbladder may sometimes be seen.
Related pathology
