Chapter 1 Down Syndrome: Historical and Ethical Perspectives -- Chapter 2 Down Syndrome: Genetics and Clinical Features -- Chapter 3 Ultrasound markers of aneuploidy at 11-14 weeks -- Chapter 4 Maternal Serum Markers used for Screening -- Chapter 5 Single-step maternal serum screening and pre-test counseling -- Chapter 6 Non-invasive Prenatal Screening (NIPS) -- Chapter 7 Limitations of NIPS -- Chapter 8 Interpreting normal and abnormal screening reports and post-test counseling -- Chapter 9 Second Trimester Soft Markers for Aneuploidy -- Chapter 10 Invasive Testing for aneuploidy -- Chapter 11 Aneuploidy screening in Twins -- Chapter 12 Putting It All Together: A Stepwise Approach -- Chapter 13 Integrated, Contingent, and Sequential Screening -- Chapter 14 Special situations in screening -- Chapter 15 Trisomy 13, Trisomy 18 and Other Aneuploidies -- Chapter 16 Screening for Pre-eclampsia -- Chapter 17 Screening for Open Neural Tube Defects.