Genetic Testing

Genetic disorders are caused by changes or “mutations” in a person’s genes.  While most babies are born healthy, approximately 3-5% of babies are born with a birth defect.  Some of these defects are caused by a genetic disorder. 

Prenatal genetic testing is focused on identifying whether or not a baby will be born normal and healthy.  It tests for conditions such as Down’s syndrome, Turner Syndrome, and other abnormalities which may be incompatible with life.  Various types of genetic testing have been developed including both screening tests and diagnostic tests. Prenatal screening tests will tell you the chance your baby has for an abnormality in the genes; it does not confirm a diagnosis and it may include false-positive (a positive result when the baby is actually normal) or false-negative (a negative result when the baby is actually affected) results.  Prenatal diagnostic tests can tell you whether or not your baby actually has a genetic abnormality.  However, these tests are invasive and require obtaining cells from the placenta or the amniotic fluid. 

While prenatal genetic testing is concerned with the genes of the baby, carrier screening analyzes the genes of the mother and/or father to determine whether or not they have abnormalities which can pass to their baby. Normally humans have two copies of every gene.  For certain genetic disorders to occur, a person must have two damaged copies of the gene.  As long as a person has at least one working copy of the gene, he or she is healthy and usually has no signs or symptoms of the genetic disorder.  People who have one working copy and one damaged copy are called “carriers.”  It is estimated that we all “carry” at least 8-10 damaged genes in our DNA. While having only one damaged gene does not affect us, if we have children with someone who also carries a damaged copy of the same gene, these children are at increased risk for inheriting both damaged genes and having the genetic disorder. 

The American College of Obstetricians & Gynecologists recommends that all women be offered testing.  It is a personal decision on whether or not to have genetic testing or carrier screening and your individual beliefs and values are important factors in this decision.  Some pregnancies are at increased risk of birth defects or genetic disorders.  These include mothers over the age of 35 at the time of delivery, a personal or family history of a birth defect or genetic disorder, and various other situations.  Our team can help decide if genetic testing is right for you.  Carrier screening is recommended to all people who are pregnant or planning on becoming pregnant.  The results of a carrier screen do not change from pregnancy to pregnancy and therefore patients only need to be tested one time. 

Various lab tests are available to perform genetic testing.  We recommend the most accurate screening test called cell-free DNA testing. This non-invasive prenatal test (NIPT) is performed on blood drawn from the pregnant mother as early as 10-12 weeks of pregnancy.  At the same time, blood for carrier screening can be obtained and tested.  Results typically take 10-14 days to return. 

If positive results are encountered for genetic testing, your physician will discuss your options with you and can refer you to have diagnostic testing performed to confirm or disprove the results.  If a carrier screening result is positive, then the father of the baby will be offered testing.   If he is negative, the baby can not be affected;  if he is positive, we can refer you to a genetic counselor and for diagnostic testing to determine whether or not the baby is affected.  When both parents are carriers, there is a 25% change the baby will be affected. 

Prenatal genetic testing and carrier screening tests are covered by most insurance companies, especially if patients have a high risk pregnancy.  For those without insurance or a plan that does not cover testing, several medical companies offer patient assistance programs or low out-of-pocket options to make the tests affordable. 

If you’re pregnant or planning on getting pregnant soon, and are interested in genetic testing, set up a consultation with us at Alliance Obstetrics & Gynecology and The Center for Pediatric & Adolescent Gynecology.