The report of 4D ultrasound examination often contains some indicators that indicate whether the baby is developing normally, such as biparietal diameter, head circumference, femur length, abdominal circumference, lateral ventricle width, amniotic fluid index, fetal heart rate, etc. These developmental indicators are commonly expressed in data. 1. The normal fetal heart rate is between 120-160 beats per minute, exceeding this range is abnormal. 2. The length of the femur and the biparietal diameter generally increase with the increase of the gestational week. 2, most babies’ femur length is 20-30mm less than the biparietal diameter, exceeding this range is abnormal. 3, the width of the baby’s lateral ventricle should not exceed 10mm, more than 10mm is abnormal. 4, the depth of amniotic fluid is between 3-8cm; the amniotic fluid index is between 8-18cm, exceeding this range is abnormal.