RT Book, Section A1 Pyeritz, Reed E. A2 Papadakis, Maxine A. A2 McPhee, Stephen J. A2 Rabow, Michael W. SR Print(0) ID 1175797780 T1 Prenatal Diagnosis of Genetic Disorders T2 Current Medical Diagnosis & Treatment 2021 YR 2021 FD 2021 PB McGraw-Hill Education PP New York, NY SN 9781260469868 LK accessmedicine.mhmedical.com/content.aspx?aid=1175797780 RD 2023/02/06 AB It is possible to diagnose in utero, before the middle of the second trimester, mendelian disorders for which a gene is associated, all chromosome aberrations, and a number of congenital malformations that are not mendelian. The first step toward prenatal diagnosis is taken when the expecting couple, the primary care provider, or the obstetrician thinks of the need for it. However, even for the most common indication for such service—advanced maternal age—less than 50% of all women 35 years and older in the United States are offered prenatal testing.