Fetal biparietal diameter of 8.3cm and femur length of 6.0cm need to be combined with gestational weeks to determine whether they are normal. Biparietal diameter and femur length change with the increase of gestational weeks, both are fetal growth parameters, need to be combined with the gestational weeks to speculate whether the fetus has abnormal growth and development, fetal biparietal diameter of 8.3cm and femur length of 6.0cm, about the size of the gestational weeks of 33 weeks. Biparietal diameter refers to the widest length between the parietal processes on both sides of the fetus; femur length refers to the length of the fetus’ thigh bone. There are clinical reference tables for biparietal diameter and femur length for each week of pregnancy. If the biparietal diameter is disproportionate to the femur length, it is possible that the examiner has made a mistake in the measurement method, or there may be fetal abnormalities, and further chromosomal examination may be necessary. During pregnancy, it is recommended that the mother attends regular checkups, intervenes promptly when abnormalities are detected, and consults a medical professional.