The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Chorionic villus sampling (CVS) is a form of prenatal testing, completed earlier in gestation than the more traditional testing method, amniocentesis. Through CVS, the fetus's genetic material can be examined, and common chromosomal disorders and hereditary conditions, as well as the baby's sex, can be identified.
CVS can be performed in two ways. In transcervical testing, a thin tube is inserted through the cervix and into the uterus. Guided by ultrasound, the tube suctions microscopic projections called chorionic villi from within the placenta, that which contain the same genetic material as does the fetus. These same fibers are extracted by transabdominal CVS, when a thin needle is inserted through the abdomen into the uterus. Again, ultrasound assists in identifying the exact location of the placenta.
The advantage of the CVS procedure is that it can be completed as early as 10 weeks in the pregnancy, but preferably closer to 12 or 13 weeks, and results are usually available within 48 hours. Amniocentesis is not done until the 15th to 19th week, and results can take up to two weeks. CVS was initially considered riskier because of increased chance of miscarriage or limb defects. With advances in procedure and training since its introduction in 1983, however, CVS is now considered as safe as amniocentesis and the preferred method for physicians to obtain early genetic information about the fetus.