TY - CHAP M1 - Book, Section TI - Pregnancy A1 - McCarthy, Jeanette J. A1 - Mendelsohn, Bryce A. PY - 2016 T2 - Precision Medicine: A Guide to Genomics in Clinical Practice AB - For decades, the only application of genetic screening that most individuals would ever encounter was testing for aneuploidies in pregnant women, particularly those over age 35. The risk of a fetus being affected by Trisomy 21 (discussed as a clinical entity in Chapter 3) increases gradually as a woman ages, and 35 was somewhat arbitrarily selected as the age at which the risk of Trisomy 21 was sufficiently high to justify testing by amniocentesis or chorionic villus sampling (CVS), each of which carries with it a very small risk of miscarriage or other fetal complications. However, the majority of children with Trisomy 21 are born to women younger than 35, simply because younger women have disproportionately more children than their reduced risk for Trisomy 21. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - accessmedicine.mhmedical.com/content.aspx?aid=1134734762 ER -