Many checkups during pregnancy are mandatory, including various blood tests, four-dimensional ultrasound, Down’s syndrome screening and so on. 1. Blood test: including blood and urine routine, biochemistry, coagulation, infectious diseases, blood type and other tests. 2. 4D ultrasound: it is an ultrasound for malformation, which can observe the development of the fetus and exclude abnormalities such as cleft lip, missing ear, congenital heart defects and so on. 3. Down’s syndrome screening: it is mainly to extract the serum of pregnant women for examination, from which it can observe whether there is trisomy 21, trisomy 18 and other abnormalities, and then exclude fetal neural tube malformation. In addition to the above tests, there are other tests during pregnancy that should be performed under the guidance of a physician.