At 12 weeks of pregnancy, what should the crown-rump length be?

Patient's question:

No

Doctor's answer:

There are several formulas for estimating fetal weight:
Formula 1: Y = 260.69HC - 4973.72
Formula 2: Y = 171.48AC - 2686.60
Formula 3: Y = 747.42FL - 2232.56
Where Y is the fetal weight, measured in grams. AC is the abdominal circumference, HC is the head circumference, and FL is the femur length, measured in centimeters.