Everything There is to Know about Prenatal DNA Testing
By the time you reach pregnancy week 9, your baby is just about the size of a cherry. Even so, little organs are beginning to develop. Although this life is still brand-new, it has its own unique human genome. In fact, the 46 chromosomes that make up all of the fetus’s characteristics are present shortly after the egg and sperm combine to form a zygote, far before you know that you’re pregnant. These chromosomes determine physical features, and they carry important information that can determine whether any genetic disorders are present.
When is prenatal DNA testing conducted?
Screening tests are conducted to evaluate the risk for common genetic disorders such as Down Syndrome, Cystic Fibrosis, Fragile X Syndrome, Muscular Dystrophy, Huntington’s Disease, and many others. In most cases, they occur during the first trimester, usually between weeks 10 and 13. Second trimester testing is less common, but is equally informative. According to the Centers for Disease Control, most birth defects occur during the first trimester. They can, however, occur at any time.
What is the risk that my baby might have a birth defect?
The CDC states that birth defects affect one of every 33 babies born in the US each year. Some birth defects can be attributed to lifestyle factors such as smoking and alcohol use during pregnancy; others are connected to the mother’s age or medical conditions, and still others are inherited. Not all birth defects are severe or life-threatening; some like cleft palates are relatively easy to resolve; others require special care throughout life.
Is prenatal DNA testing necessary for all women?
While testing provides important information, it’s up to each woman to determine whether testing is necessary. Knowing that a baby might be born with a birth defect can help prepare for special circumstances after birth, but it might also increase stress. If you are concerned about the implications, talk to your health care provider to determine next steps.
What information will a prenatal DNA test provide?
There are different types of prenatal DNA tests, and each provides different information. Genetic screening, for example, measures the risk that a genetic disease will be present. Cell-free fetal DNA testing screens for specific genetic disorders including Down syndrome, trisomy 13, and trisomy 18. Also known as cfDNA screening, it measures risk rather than providing a diagnosis. Definitive tests including amniocentesis and CVS (chorionic villus sampling) are typically provided in cases where previous testing show positive results, and may also be provided on their own.
Will my insurance cover prenatal DNA testing?
Most insurance plans cover DNA testing when there is an elevated risk for genetic birth defects; however, it’s best to check your specific plan to see what is and is not included, and whether the tests your health care provider recommends are covered.
Which method of testing should I ask for?
Your health care provider will guide you through the testing process, and the methods used will depend on which genetic disorders might or might not be present. In many cases, having your own blood tested determines whether there is a need for CVS or amniocentesis.
Sources:
https://www.livescience.com/45949-prenatal-genetic-testing.html
http://blogs.plos.org/dnascience/2013/10/03/when-does-a-human-life-begins-17-timepoints/
http://baby2see.com/development/first_trimester.html