Down’s screening for pregnant women is usually recommended twice. Down’s syndrome screening for pregnant women is divided into early Down’s syndrome screening and mid-term Down’s syndrome screening. Early Down’s syndrome screening is an ultrasound examination of the posterior cervical zona pellucida at 11-13+6 weeks of gestation and blood sampling to do early Down’s syndrome screening, and mid-term Down’s syndrome screening is a combination of blood sampling and combining with the age of the pregnant woman and the week of gestation to determine whether there is any risk of congenital hereditary diseases for the fetus at 15-20 weeks of gestation. If the pregnant woman is over 35 years old or the results of the early Down’s screening are abnormal, it is recommended to undergo the intermediate Down’s screening, or directly do non-invasive DNA or amniocentesis. After pregnancy, it is recommended to do regular and good maternity checkups at each stage of pregnancy to improve the detection rate of Down’s babies through early Down’s screening and midterm Down’s screening.