RT Book, Section A1 Wapner, Ronald J. A1 Toy, Eugene C. A2 Fleischer, Arthur C. A2 Toy, Eugene C. A2 Lee, Wesley A2 Manning, Frank A. A2 Romero, Roberto J. SR Print(0) ID 1106709080 T1 CHORIONIC VILLUS SAMPLING T2 Sonography in Obstetrics and Gynecology: Principles & Practice, 7e YR 2015 FD 2015 PB McGraw-Hill Education PP New York, NY SN 9780071547727 LK obgyn.mhmedical.com/content.aspx?aid=1106709080 RD 2024/03/18 AB DefinitionsChorionic villus sampling (CVS): an invasive procedure performed for first-trimester prenatal diagnosis. CVS is typically performed between 70 and 91 days after the LMP. In the procedure, tissue is withdrawn from the villi (vascular fingers) of the chorion, a part of the placenta, and examined.Chorion frondosum: the cellular, outermost extraembryonic membrane, composed of trophoblastic cells, and develops villi, and forms the fetal component of the placenta.Fluorescent in situ hybridization (FISH): rapid method of assessing targeted chromosomal abnormalities such as trisomy 21, 18, or 13.First-trimester screening: a method of screening for chromosomal abnormalities in the first trimester using two biochemical tests, PAPP-A and hCG as well as sonographic nuchal translucency measurement.