NORTHWEST ARKANSAS PRENATAL GENETIC SCREENING
Cell free Fetal/ Twin DNA screen
Cell Free Fetal/Twin DNA screening test is a non-invasive test that detects common fetal genetic disorders and fetal gender in pregnancies of 10 weeks or more, based on directed analysis of fetal DNA in maternal blood.
Cell Free Fetal/Twin DNA screening test detects trisomies of chromosomes 21, 18 and 13 or sex chromosome (X or Y) abnormalities in the fetus, but does not rule out all fetal abnormalities.
Humans have 23 pairs of chromosomes, which are strands of DNA and proteins that carry genetic information. A trisomy is a chromosomal condition that occurs when there are three copies of a particular chromosome instead of the expected two.
Trisomy 21 is due to an extra chromosome 21 and is the most common trisomy at the time of birth. Trisomy 21, also called Down Syndrome, is associated with mild to moderate intellectual disabilities and may also lead to digestive disease and congenital heart defects. It is estimated that trisomy 21 is present in 1 out of every 700 newborns.
Trisomy 18 is due to an extra chromosome 18. Trisomy 18, also called Edwards Syndrome, is associated with a high rate of miscarriage. Infants born with trisomy 18 often have congenital heart defects as well as various other medical conditions, shortening their lifespan. It is estimated that trisomy 18 is present in approximately 1 out of every 5,000 newborns.
Trisomy 13 is due to an extra chromosome 13. Trisomy 13, also called Patau Syndrome, is associated with a high rate of miscarriage. Infants born with trisomy 13 usually have severe congenital heart defects and other medical conditions. Survival beyond the first year is rare. It is estimated that trisomy 13 is present in approximately 1 out of every 16,000 newborns.
Cell Free Fetal/Twin DNA screening test assesses the risk of three fetal trisomies by measuring the relative amount of chromosomes in maternal blood.
Cell Free Fetal/Twin DNA screening test is based on the newest advances in non-invasive prenatal testing. It is a simple and safe blood test that has been shown in clinical studies to detect the risk of fetal trisomies with high accuracy.
Cell Free Fetal/Twin DNA screening test has been shown to have detection
rates of up to 99% and false positive rates as low as 0.1% for trisomy 21, 18 and 13. Diagnostic tests such as amniocentesis or chorionic villus sampling (CVS) are accurate for detecting fetal trisomies, but they are invasive and pose a slight risk for fetal loss.
Cell Free Fetal/Twin DNA screening test can be ordered by healthcare professionals for women with pregnancies of at least 10 weeks’ gestational age. The test is not for use in multiple pregnancies (such as twins) or egg-donor pregnancies.
Cell Free Fetal/Twin DNA screening test may be offered for:
Maternal age 35 years or older at delivery
Fetal ultrasonographic findings indicating an increased risk of aneuploidy
History of a prior pregnancy with a trisomy
Positive test result for aneuploidy, including first trimester, sequential, or integrated screen, or a quadruple screen.
Parental balanced robertsonian translocation with increased risk of fetal trisomy 13 or trisomy 21.
Cell Free Fetal/Twin DNA screening test does not screen for open neural tube defects. Open neural tube defects occur when the baby’s neural tube does not close completely and an opening remains along part of the baby’s spine or head. Open neural tube defects occur in about 1 out of every 1,500 live births.6 A second trimester blood test called MSAFP, or an ultrasound, is required to detect open neural tube defects
Low Risk result
If the Cell Free Fetal/Twin DNA screening test results show a Low Risk, the chance of having a baby with trisomy 21, trisomy 18, or trisomy 13 is low. As with any test, a low risk result reduces, but does not eliminate, the chance of having an affected pregnancy.
High Risk result
If the Cell Free Fetal/Twin DNA screening test results show a High Risk, there is an increased chance of having a baby with trisomy 21, trisomy 18, or trisomy 13. If your result is High Risk, your healthcare provider may offer genetic counseling and/or diagnostic testing to determine if your baby is affected with one of these conditions.