The chapter’s contribution to the book explores the prenatal modalities to diagnose Down syndrome (DS). The current knowledge in the field of genetic sonographic markers is presented, along the performance of current policies as well as the potential of new emerging genetic techniques. Besides the screening or testing pregnancy algorithms, the chapter describes the power of prenatal diagnostic techniques, namely, the advantages and the complications of the invasive genetic maneuvers. The progress in prenatal diagnosis of Down syndrome is one of the most important in prenatal medicine in the last decades. The methods vary in terms of detection rates, acceptability, costs, and potential complications. Although the early genetic screening was improved, ultrasound evaluation should not be dismissed, as the first-trimester sonography has the potential to diagnose the majority of major fetal abnormalities
