Fetal femur length standard comparison table is the comparison table of pregnancy weeks and the corresponding fetal femur length, femur length is an important indicator to evaluate the fetal physical development, with the increase of pregnancy weeks fetal physical development speed up, the length of the femur will gradually change. At 12 weeks of pregnancy, the fetal femur is about 7mm long, at 16 weeks of pregnancy it is about 20mm long, at 20 weeks of pregnancy it is about 32mm long, at 24 weeks of pregnancy it is about 43mm long, at 28 weeks of pregnancy it is about 53mm long, at 32 weeks it is about 62mm long, at 36 weeks it is about 70mm long and at 40 weeks it is about 78mm long. This table is the standard comparison table for fetal femur length.