The cost of Down’s syndrome screening varies from hospital to hospital, depending on the city and the level of the hospital district, and is generally around $200-300. Down’s syndrome screening is performed on an empty stomach to detect the possibility of conception of a fetus with congenital defects by testing the pregnant woman’s serum markers, with the aim of minimizing the birth rate of abnormal fetuses. The best time for Down’s syndrome screening is between the 14th and 22nd week of pregnancy. If the result of Down’s syndrome screening is high risk, further chorionic villus biopsy, amniocentesis and fetal chromosome examination should be performed for a definite diagnosis. The risk factor for Down’s syndrome is calculated by measuring maternal serum for alpha-fetoprotein, chorionic gonadotropin and free estriol, and taking into account the expected date of delivery, weight, age and week of pregnancy at the time of blood collection. Therefore, during prenatal screening, pregnant women should provide detailed personal information, including date of birth, last menstrual period, weight, whether they smoke, and whether they have insulin-dependent diabetes mellitus. The Down’s syndrome screening value is a modified value, and the factors affecting this indicator are mainly maternal age, weight, gestational week, fetal secretion of alpha-fetoprotein, human chorionic gonadotropin secreted by the placenta, medications, genetics, etc. The influence of the above factors should also be considered in case of abnormalities.