Mid-Tang refers to the mid-term Down screening. The next obstetric examination after the mid-term Down screening is the fetal system ultrasound examination between 20 and 24 weeks of pregnancy, which can be conducted under the guidance of the physician. Standardized and reasonable obstetrical examination during pregnancy can detect pregnancy complications or complications and fetal abnormalities at an early stage. After completing the mid-trimester Down’s syndrome screening at 15 to 20 weeks of gestation, the next fetal systematic ultrasound examination between 20 and 24 weeks of gestation should be performed, which can promptly detect the risk of fetal structural malformations, such as anencephaly, severe brain enlargement, and a single-chambered heart, etc. The labor tests can be performed on time as instructed by the physician. During pregnancy, relevant laboratory tests should also be carried out on time in accordance with the doctor’s instructions, so as to detect pregnancy complications, such as anemia in pregnancy, hypertension in pregnancy, diabetes in pregnancy, etc., and provide timely intervention and treatment in order to reduce the risk of pregnancy, assess the safety and danger of the pregnant woman and the fetus in a timely manner, and specify the mode and timing of delivery, so as to ensure the safety of mothers and infants.