sts are typically offered between fifteen and twenty weeks of gestation. Screening tests are of limited value and are often performed in conjunction with a detailed sonogram. These tests are only able to accurately detect about sixty percent of fetuses with Down syndrome. (National Down Syndrome Society) Many women who undergo these tests will be given false-positive readings, and some women will be given false-negative readings. The procedures available for prenatal diagnosis of DS are chorionic villus sampling (CVS), amniocentesis and percutaneous umbilical blood sampling (PUBS). Each one of these procedures carries a small risk of miscarriage as tissue is extracted from the placenta or the umbilical cord to examine the fetus' chromosomes. The procedures are about 98 to 99 percent accurate in the detection of Down syndrome. (National Down Syndrome Society) Amniocentesis is usually performed between 12 and 20 weeks of gestation, CVS between eight and 12 weeks and PUBS after 20 weeks. The diagnosis of DS is usually suspected after birth as a result of the baby's appearance. It is a particularly difficult time, coupled with the natural stresses of childbirth. Although there is no easy way to be informed, most families agree that having the baby present, being together and being told as soon as possible is the best way to proceed. There are many physical characteristics which form the basis for suspecting an infant has Down syndrome. Many of these characteristics are found, to some extent, in the general population of individuals who do not have DS. Hence, if Down syndrome is suspected, a karyotype will be performed to ascertain the diagnosis. Some infants with DS have only a few of these traits, while others have many. Among the most common traits (with corresponding percentage of frequency) are; oblique (upslanting) palpebral fissures (82%), loose skin on nape of neck (81%), narrow palate (76%), brachyclephaly (75%), flat nasal bridge (...
