Genetic testing before and during pregnancy Find out what genetic tests are and whether you and your partner should be tested before pregnancy. What is genetic testing (carrier screening)? genetic screening tests Genetic testing is when a blood test is given to prospective or anticipated parents to look for abnormal genes that can lead to certain diseases in their baby. Most genetic diseases are known as "recessive disorders," which means that each parent must pass an affected gene to the baby for the child to be affected. In other words, if you test positive for a genetic anomaly, but your partner does not, your child will not inherit the disease. And even if you rate both positive, there is only a 25 percent chance that your baby will have the disease. You can get a carrier screening in the office of your ob-gyn with a single blood test; In general, you will receive the results in two weeks. Most often, a woman is first tested (just because you're more likely to visit your doctor when you're in the "try to receive" mode), and if those results do not show a problem gene, your partner usually does not do anything. T has to be tested. When should you get genetic testing? Ideally, genetic tests are performed before you start to get pregnant, says Angela Trepanier, MS, CGC, co-director of the genetic counseling program at Wayne State University and president of the National Society for Genetic Consultants. "But because so many pregnancies are unplanned, many couples are screened early in pregnancy," she says. If you are screened before attempting to get pregnant, you can be reassured (if you or your partner are not a carrier, it's one thing you need to worry about when you get pregnant), or you can have an informed schedule to create a pregnancy. If it turns out you're both carriers, you can be prepared for what it means to have a baby with the genetic makeup, read up on certain prenatal tests to see if your baby is healthy, or you can help others account. Options such as egg or sperm donation or adoption. If you are being tested, as soon as you get pregnant (if you have not already done so before treatment), you and your doctor can help you decide on the right prenatal tests for your baby and what to look for if you are up for it decide. For example, if you know that your baby is at an increased risk of developing Cystic Fibrosis or Sickle Cell Disease, your doctor may diagnose these conditions through either CVS (chorionic villus sampling) or amniocentesis. Who should get genetic tests? Your ethnic background and family history are the key factors that determine whether genetic testing is right for you or not. "That's because the diseases that are currently being tested for genetic testing are more common in certain ethnic groups," says
Trepanier. Here is an example of groups that are more likely to have certain genetic diseases. European Caucasians and Eastern European Jews are at increased risk for cystic fibrosis. • Eastern European Jews also face an increased risk of conditions such as Tay-Sachs, Canavan, and familial dysautonomia. African Americans and people of Mediterranean descent (Greeks, Turks, Italians) are at an increased risk for diseases such as sickle cell anemia and thalassemia. People of Southeast Asian descent are also faced with an increased risk of thalassemia. French Canadians are at increased risk for Tay-Sachs and cystic fibrosis. Although there are many other recessive genetic diseases, they are not routinely reviewed because they are either very, very rare or because the right tests have not yet been developed, Trepanier says. What are some of the common genetic diseases? Cystic fibrosis is a life-threatening disease that causes lung damage and digestive problems. About 30,000 people in the US have the disease, which affects mainly Caucasians of Northern European descent. Organizations such as the National Institutes of Health, the American College of Obstetricians and Gynecologists, and the American College of Medical Genetics have recommended nationwide genetic testing for CF for all adults since 2002. According to a recent New England Journal of Medicine study, the number of cystic fibrosis babies in Massachusetts declined by about 50 percent in the four years after this recommendation was made and the tests were more widely used compared to the previous four years. The disease of sickle cells, most common in people with African and Mediterranean