Down’s screening for pregnant women is short for prenatal screening test for Down’s syndrome, which tests the concentration of alpha-fetoprotein, chorionic gonadotropin and free estriol in the mother’s serum to determine the risk of the three genetic disorders. Down’s syndrome screening is one of the mandatory screening programs during pregnancy. It mainly tests the maternal blood for concentrations of alpha-fetoprotein, chorionic gonadotropin and estrogen, and based on the results of these tests, combined with the actual condition of the pregnant woman, the doctor can estimate the risk of the fetus suffering from the three genetic abnormalities, including trisomy 21, trisomy 18, and congenital spina bifida. If the Down’s syndrome test indicates a high risk, the pregnant woman will need to undergo further labor and delivery tests for diagnosis.