The main check for fetal abnormalities is the ultrasound of 22-24 weeks, which is the ultrasound of 22-24 weeks to see if the fetus has structural abnormalities, soft ultrasound indicators, and whether the size of the fetus is consistent with the development of the gestational week, and also to see whether the fetal appendages, that is, the placenta, umbilical cord and amniotic fluid have any problems. The major teratology is to scan the whole body structure of the fetus with ultrasound, as follows: 1. intracranial: the most important structure of the cranium, to see if there is hydrocephalus, widening of the lateral ventricles, and other possible problems; 2. chest and lungs: the chest to see if there are any abnormalities in the fetal heart structure, whether there is congenital heart disease, whether there is isolated lung, cystic adenoma and other problems in the lungs; 3. abdomen: to observe the development of gastric alveoli The development of liver, gallbladder, spleen and kidneys is normal; 4. limbs: observe whether the length of the long bones of the limbs matches the gestational week, and whether there is any possibility of short limbs and abnormal development; 5. fetal appendages: see where the placenta is attached to the uterus, and whether there is any low position of the placenta; see whether there is too much or too little amniotic fluid, whether the umbilical cord is wrapped around the neck, and whether there is any abnormal umbilical blood flow, etc. There are no abnormalities in the umbilical cord blood flow and so on. The screening ultrasound at 22-24 weeks can detect problems related to fetal structural abnormalities. If these problems are found, further tests should be done to assess the impact on the future quality of life of the fetus.