Mini-detectorial examination is mainly to supplement the detector as well as monitor the growth and development of the fetus, which can rule out some fetal developmental abnormalities that appear only in late pregnancy, and understand the position of the fetus, the position and maturity of the placenta, amniotic fluid, and so on. It does not mean that the micro-analysis is an ordinary color ultrasound. There are currently three types of mini ultrasound available: 2D ultrasound, 3D ultrasound and 4D ultrasound. Usually, in most cases, the doctor will usually use ordinary ultrasound to perform systematic screening, but if the pregnant woman wants to see the baby’s appearance, she can add 3D or 4D ultrasound, but she can’t use 3D or 4D ultrasound solely without ordinary ultrasound.