Down’s syndrome screening is an abbreviation for prenatal screening test for Down’s syndrome, a test of special significance. The purpose of the test is to detect the concentration of alpha-fetoprotein, chorionic gonadotropin and free estriol in maternal serum by testing the blood of the pregnant woman. The test is done in conjunction with the mother’s age, weight, and gestational age to determine the risk factor for congenital dysmorphism and neural tube defects. Once the fetus is diagnosed with Down’s syndrome, the pregnancy should be terminated promptly.