What Is the Process of Finding Out if a Baby Has Down Dyndrome Called

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Health intendance providers can check for Down's syndrome during pregnancy or after a child is built-in. In that location are 2 types of tests for Down syndrome during pregnancy:

A prenatal screening test. This test can evidence an increased likelihood that a fetus has Down syndrome, but it cannot make up one's mind Down syndrome is definitely present. If a screening test shows an increased likelihood, a diagnostic test tin can be ordered.
A prenatal diagnostic test. This test tin can make up one's mind with certainty that Down's syndrome is nowadays. Diagnostic tests carry a slightly greater risk to the fetus than do screening tests.

The American Congress of Obstetricians and Gynecologists (ACOG) recommends that all meaning women be offered a Down syndrome screening test.¹

Prenatal Screening for Down Syndrome

There are several options for Down syndrome prenatal screening. These include:

A claret test and an ultrasound test during the outset trimester of pregnancy. This is the nigh accustomed approach for screening during the first trimester. A blood examination enables a health care provider to bank check for "markers," such as sure proteins, in the mother's blood that suggest an increased likelihood of Downwards syndrome.ⁱⁱ So the health intendance provider does an ultrasound test, which uses loftier-frequency audio waves to create images. An ultrasound can find fluid at the back of a fetus's neck, which sometimes indicates Down syndrome. The ultrasound exam is called measurement of nuchal translucency. During the first trimester, this combined method results in more effective or comparable detection rates than methods used during the 2nd trimester.³
A blood test during the 2d trimester of pregnancy. As in the commencement trimester, a blood test enables a health intendance provider to cheque for markers in the mother's blood. A triple screen looks for levels of three dissimilar markers; a quadruple screen looks for levels of four different markers.^3,four
A combined test (sometimes chosen an integrated test). This arroyo uses both a blood test and an ultrasound during the first trimester as well equally a second-trimester blood exam. Health intendance providers then combine all these results to produce one Down syndrome risk rating.²

If a woman is pregnant with twins or triplets, a blood exam will non be as reliable because the substances from a Down's syndrome fetus may be harder to detect.^2,3

Prenatal Diagnostic Testing for Downwardly Syndrome

If a screening exam suggests the likelihood of Down syndrome, a diagnostic examination can be performed. ACOG recommends that pregnant women of all ages be given the choice of skipping the screening examination and getting a diagnostic test first. Until recently, but women over age 35 and other at-take chances women were offered this option because diagnostic tests carry a slight adventure of miscarriage.ⁱ Earlier having diagnostic testing, a pregnant adult female and her family unit may want to see with a genetic counselor to talk over their family history and the risks and benefits of testing in their specific situation.

Diagnostic testing for Down's syndrome involves removing a sample of genetic material. Later on it is removed, the sample is checked for actress material from chromosome 21, which may point that a fetus has Down syndrome. Parents usually get the results of the test a week or two later. The following procedures are used to excerpt samples.

Amniocentesis (pronounced am-nee-oh-sen-TEE-sis). A health intendance provider takes a sample of amniotic (pronounced am-nee-OT-ik) fluid, which is then tested for the extra chromosome. This exam cannot be done until week 14 to 18 of the pregnancy.
Chorionic villus (pronounced KOHR-ee-on-ik VIL-uhs) sampling (CVS). A health care provider takes a sample of cells from a role of the placenta (pronounced pluh-SEN-tuh), which is the organ that connects a woman and her fetus, and so tests the sample for the extra chromosome. This exam is washed between weeks 9 and eleven of pregnancy.
Percutaneous (pronounced pur-kyoo-TEY-nee-uhs) umbilical claret sampling (PUBS). A health intendance provider takes a sample of fetal blood in the umbilical string through the uterus. The blood is then tested for the extra chromosome. PUBS is the most accurate diagnostic method and can ostend the results of CVS or amniocentesis. Nonetheless, PUBS cannot be performed until later in the pregnancy, during the 18th to 22nd week.^v

Prenatal diagnostic testing does involve some hazard to the mother and fetus, including a slight risk of miscarriage.^6,7,8,9 If you lot and your family unit are considering prenatal diagnostic testing for Down syndrome, discuss all the risks and benefits with your health care provider.

Chromosomal Testing of Maternal Blood

A significant woman who is at take chances for having an infant with Downwardly syndrome also tin have a chromosomal examination using her blood. A mother's blood carries DNA from the fetus, which may show extra chromosome 21 fabric.^three A more invasive test then would usually confirm the blood examination.

Testing and In Vitro Fertilization

Another approach to diagnosis is used in conjunction with in vitro fertilization. Preimplantation genetic diagnosis (PGD) allows clinicians to detect chromosome imbalances or other genetic conditions in a fertilized egg before it is implanted into the uterus.

This technique is useful mostly for couples who are at risk of passing on a diverseness of genetic conditions, including X-linked disorders, likewise equally couples who accept suffered repeated spontaneous pregnancy losses, sub-fertile couples, or those at risk for single-gene disorders.

Those interested in PGD should take genetic counseling and should consider shut monitoring and boosted testing during their pregnancies, given some increased risk of chromosomal abnormalities arising secondary to the in vitro fertilization process.¹⁰

Diagnosis of Down Syndrome After Nascence

A diagnosis of Down syndrome after birth is often based initially on physical signs of the syndrome.

Merely because individuals with Down syndrome may not take these symptoms, and considering many of these symptoms are common in the general population, the health intendance provider will take a sample of the baby's blood to confirm the diagnosis. The blood sample is analyzed to determine the number of the baby'southward chromosomes.¹¹

Citations

Close Citations

American Congress of Obstetricians and Gynecologists (ACOG). (2007, May vii). ACOG's screening guidelines on chromosomal abnormalities [News release]. Retrieved June 11, 2012.
Driscoll, D. A., & Gross, S. (2009). Prenatal screening for aneuploidy. New England Periodical of Medicine, 360, 2556–2562.
Ehrich, M., Deciu, C., Zwiefelhofer, C., Tynan, J. A., Cagasan, L., Tim, R., Lu, Five., et al. (2011). Noninvasive detection of fetal trisomy 21 by sequencing of Deoxyribonucleic acid in maternal blood: A study in a clinical setting. American Journal of Obstetrics & Gynecology, 204, 201–211.
ACOG. (2011). Routine tests in pregnancy. Retrieved June 11, 2012, from http://www.acog.org/~/media/For%20Patients/faq133.pdf?dmc=1&ts=20120611T1510306056 (PDF - 218.20 KB)
American Association for Clinical Chemistry. (2012). Second trimester: Cordocentesis (percutaneous umbilical claret cord sampling, PUBS). Retrieved June eleven, 2012, from https://labtestsonline.org/conditions/pregnancy-second-trimester-13-27-weeks
Caughey, A. B., Hopkins, L. M., & Norton, M. E. (2006). Chorionic villus sampling compared with amniocentesis and the deviation in the charge per unit of pregnancy loss. Obstetrics and Gynecology, 108, 612–616.
Evans, M. I., & Wapner, R. J. (2005). Invasive prenatal diagnostic procedures 2005. Seminars in Perinatology, 29, 215–218.
Daniilidis, A., Karydas, H., Zournatzi, V., Tantanasis, T., Giannoulis, C., & Tzafettas, J. (2008). A 4-year retrospective study of amniocentesis: I centre experience. Hippokratia, 12, 113–115.
ACOG. (2007). ACOG Practice message: Invasive prenatal testing for aneuploidy. Retrieved June 11, 2012, from https://www.ncbi.nlm.nih.gov/pubmed/18055749 (PDF - 160 KB)
Hanna, K. Due east. (2006). Reproductive genetic testing. Retrieved June xi, 2012, from the National Man Genome Inquiry Institute website: http://www.genome.gov/10004766
National Human Genome Inquiry Constitute. (2010). Learning virtually Down syndrome . Retrieved June eleven, 2012, from http://world wide web.genome.gov/19517824#3