Early pregnancy Down’s syndrome screening is performed at 10 – 13+6 weeks of gestation, which is a different time from the previous mid pregnancy Down’s syndrome screening (14-20 weeks of gestation). The purpose is to determine the risk factor of Down syndrome and neural tube defects in the fetus, that is, how probable is the risk of Down syndrome in the fetus, by detecting pregnancy-associated plasma protein-A (PAPP-A) and chorionic gonadotropin (HCG) indicators in the maternal serum, ultrasound examination of the fetal nuchal translucency (NT), and other clinical information of the mother. Clinical data show that the detection rate of early Down’s syndrome screening is much more sensitive and accurate than that of mid-pregnancy Down’s screening, which is 90-95%.