According to BabyMed, the numbers on an ultrasound provide information about whether the baby, or fetus, has grown properly and also whether the growth of the baby is within the typical range.
The letters that are next to the numbers on an ultrasound represent different measurements of the baby. BabyMed states that the gestational sac or GA can be measured by an ultrasound. The gestational sac is the intrauterine structure surrounding the area where the baby grows. Additionally, the crown-rump length or CRL can be measured. This is the distance from the top of the embryo to the bottom. The bi-parietal diameter or BPD, meaning the diameter between the 2 sides of the head, can also be measured. The femur length or FL, abdominal circumference or AC, and the estimated fetal weight or EFW can also be measured with an ultrasound.