When a woman is pregnant, a serum test, mainly a peripheral blood test, also known as Down’s syndrome screening, screens the fetus for neural tube malformations or chromosomal malformations, and it is better to conduct the test in the 16-18th week of pregnancy. If the risk is high, non-invasive DNA or amniocentesis can be performed to confirm the diagnosis of Down syndrome, which requires prompt termination of pregnancy. From the perspective of eugenics, women need to do egg and sperm quality, chromosome, genetic disease and other aspects of the test during the preparatory period before pregnancy, pregnancy on time to do pregnancy thyroid function screening, NT test, Down’s syndrome screening, non-invasive DNA, systematic ultrasound, four-dimensional ultrasound, glucose tolerance test test for observation of fetal growth and development of whether there are any abnormalities, and women routinely in the first trimester and after the pregnancy, the first three months and the second half of the pregnancy, the first three months and the second half of the pregnancy, the first three months and the second half of the pregnancy, the first three months and the second half of the pregnancy. Women are also required to take a small dose of folic acid during the first 3 months of pregnancy and the first 3 months after pregnancy, also to prevent the occurrence of fetal malformations.