Babies with Down syndrome, commonly known as \”Down syndrome babies\”, are the most common chromosomal abnormalities in my country at this stage. The main characteristics of \”Down syndrome\” are low IQ and a special face. So far, there is no effective preventive method or effective treatment for this disease in medicine. Only through prenatal screening and diagnosis can we detect it as early as possible, terminate the pregnancy, and avoid the birth of affected children. Experts remind that the following seven types of couples belong to high-risk groups: 1. Pregnant women with a history of viral infections before and after pregnancy, such as influenza, rubella, etc.; hint: \”five teratogenic items\”