Prenatal diagnostic testing does involve some risk to the mother and fetus, including a slight risk of miscarriage. However, PUBS cannot be performed until later in the pregnancy, during the 18th to 22nd week. PUBS is the most accurate diagnostic method and can confirm the results of CVS or amniocentesis. The blood is then tested for the extra chromosome. A health care provider takes a sample of fetal blood in the umbilical cord through the uterus. Percutaneous (pronounced pur-kyoo-TEY-nee-uhs) umbilical blood sampling (PUBS).This test is done between weeks 9 and 11 of pregnancy. A health care provider takes a sample of cells from a part of the placenta (pronounced pluh-SEN-tuh), which is the organ that connects a woman and her fetus, and then tests the sample for the extra chromosome. Chorionic villus (pronounced KOHR-ee-on-ik VIL-uhs) sampling (CVS).This test cannot be done until week 14 to 18 of the pregnancy. A health care provider takes a sample of amniotic (pronounced am-nee-OT-ik) fluid, which is then tested for the extra chromosome. Amniocentesis (pronounced am-nee-oh-sen-TEE-sis).The following procedures are used to extract samples. Parents usually get the results of the test a week or two later. After it is removed, the sample is checked for extra material from chromosome 21, which may indicate that a fetus has Down syndrome. 1 Before having diagnostic testing, a pregnant woman and her family may want to meet with a genetic counselor to discuss their family history and the risks and benefits of testing in their specific situation.ĭiagnostic testing for Down syndrome involves removing a sample of genetic material. Until recently, only women over age 35 and other at-risk women were offered this option because diagnostic tests carry a slight risk of miscarriage. ACOG recommends that pregnant women of all ages be given the option of skipping the screening test and getting a diagnostic test first. If a screening test suggests the likelihood of Down syndrome, a diagnostic test can be performed. 2, 3 Prenatal Diagnostic Testing for Down Syndrome If a woman is pregnant with twins or triplets, a blood test will not be as reliable because the substances from a Down syndrome fetus may be harder to detect. Health care providers then combine all these results to produce one Down syndrome risk rating. This approach uses both a blood test and an ultrasound during the first trimester as well as a second-trimester blood test.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |