Down Syndrome Tests
Down Syndrome Tests Include: Chorionic villus sampling (CVS). CVS involves taking a tiny sample of the placenta, either through the cervix or through a needle inserted in the abdomen. The advantage of this test is that it can be performed during the first trimester, between 8 and 12 weeks. The disadvantage is that it carries a slightly greater risk of miscarriage as compared with amniocentesis and has other complications.
Amniocentesis: This test, performed between 15 and 20 weeks of pregnancy, involves the removal of a small amount of amniotic fluid through a needle inserted in the abdomen. The cells can then be analyzed for the presence of chromosomal abnormalities. Amniocentesis carries a small risk of complications, such as preterm labor and miscarriage. Percutaneous umbilical blood sampling (PUBS).
Usually performed after 20 weeks, this test uses a needle to retrieve a small sample of blood from the umbilical cord. It carries risks similar to those associated with amniocentesis. After a baby is born, if the doctor suspects DS based on the infant's physical characteristics, a karyotype — a blood or tissue sample stained to show chromosomes grouped by size, number,and shape can be performed to verify the diagnosis.
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