DENVER, April 3, 2013 (GLOBE NEWSWIRE) -- Gabrielle Stewart of Denver is pregnant and over 35 years old, which puts her in the risk group with 1 in 10 expectant moms recommended to get a fetal DNA test for birth defects. But like many women facing an amniocentesis test, which involves a chance of pregnancy loss and a six-inch needle drawing amniotic fluid, Stewart was hesitant.
"I was not keen on amniocentesis, because I was very conscious of its 1 in 300 chance of ending my pregnancy," said Stewart. "So when my doctor offered a non-invasive test, I was delighted. That was a huge relief not putting my baby at risk."
Pregnant women can now opt to detect genetic abnormalities with a new, DNA blood test that carries no risk or pain. As a result, more pregnant patients of University of Colorado School of Medicine physicians are participating in testing for genetic abnormalities. Yet many women are not familiar with this option.
"This is an enormously important advancement, because we can detect the most common chromosomal problems in the first prenatal blood draw," said Dr. Teresa Harper of the University of Colorado School of Medicine Obstetrics and Gynecology Department/Maternal Fetal Medicine division. "We do away with screening tests that create anxiety with frequent false positives and we don't put moms up against a difficult decision about a very invasive test like amniocentesis and its risk of pregnancy loss."
Harper, who is Stewart's OB/GYN, has been using the cell-free DNA testing since it became available about a year ago. She published early research with her mentor on fetal DNA appearing in maternal blood.
One in 200 pregnancies involve genetic disorders, and age increases those chances, with a 40-year-old woman facing a 1 in 40 risk. Some genetic disorders are catastrophic such as Trisomy 13 or 18, in which an extra copy of chromosome number 13 or 18 means the baby is not likely to survive. Forewarned of such issues, a woman can plan for her Down syndrome child's upbringing, or consider terminating the pregnancy involving Trisomy 13 or 18.
All pregnant women over age 35 should be offered prenatal DNA testing, said Harper. So should women with a family history of a child with a genetic condition, women whose ultrasound indicates an abnormality such as Down syndrome (Trisomy 21), and those with abnormal blood screens.
Though results of the cell-free DNA test are highly accurate, women who receive a positive test result are advised to undergo amniocentesis or chorionic villus sampling, which are slightly more accurate and test for all 46 chromosomes. Current cell-free fetal DNA testing only detects eight chromosome problems, including sex chromosome issues such as Turner syndrome.
However, Harper said cell-free fetal DNA testing is advancing rapidly and has the potential to detect issues in all 46 chromosomes.
CONTACT: Media Contact: Richard Wall, Vanguard Communications 303-382-2999 RWall@VanguardCommunications.net
Source:University of Colorado OB/GYN