The first-trimester screen combines nuchal translucency measurement and serum levels ot PAPP-A and beta-hCG between 11 and 13 weeks gestational age which can be used to calculate the risk of fetal Trisomy 21 and 18. Although these trisomies are the most common conditions detected, recognition of increased risk for several other fetal conditions and maternal complications have also been documented. A common misconception is that requesting this test implies that the patient will automatically terminate an affected fetus. Although termination may be one option, it is not the primary goal of this screen. If this screen results in the discovery of an abnormal fetus, the patient is allowed maximal time for privacy, formulation of a medical management plan, preparation for caring for a child with special needs, personal research and consultation with appropriate pediatric subspecialists. This test also decreases maternal anxiety throughout pregnancy. The American College of Obstetricians and Gynecologists (ACOG) recommends that all women, regardless of maternal age and risk factors, be offered this screening test. This paper addresses how the test is performed, management of abnormal findings, risk factors and detection rates.