If you’re pregnant, it can be an anxious time, filled with worries about the health of your baby. Genetic testing allows doctors and parents-to-be the option of looking into the health of the mother and her baby and many patients ask what types of genetic tests are performed during pregnancy.
What is Genetic Testing During Pregnancy?
Before birth, doctors can conduct a blood test on the pregnant woman for certain chromosomal or genetic disorders. People with genetic disorders or with a family history can feel worried about passing on the disease to their children. Genetic testing and counseling can help determine the risks and provide you with the support you need throughout the pregnancy.
Genetic testing occurs when small samples of body tissue or blood are analyzed by your doctor. The type of medical test depends on what type of condition your doctor is checking for. These tests can help detect genes for many types of disorders. Some of the more common include cystic fibrosis, sickle cell disease, cleft palate, Tay-Sachs disease, and heart defects all can be detected before birth.
Even before pregnancy, genetic testing can look at the parent’s genes to help determine the chances that their child would have a genetic disorder. These types of tests are called carrier screening.
Why Would Families and Their Doctors Consider Genetic Testing?
Genetic testing is optional and designed to help families make informed decisions. The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant women should be offered genetic prenatal assessment regardless of maternal age or other risk factors
A doctor may make a recommendation for you to consider these tests in some of the following situations:
- If the pregnant woman is over the age of 34 when the risk of experiencing chromosomal problems in the fetus is potentially higher.
- If the woman has had two or more miscarriages or delivered a stillborn baby with a genetic illness.
- If a standard prenatal screening test has an abnormal result.
- If the parents are starting a family and a close relative has a genetic illness. There is a chance that the parent is a carrier of this genetic issue and could pass it along to their child.
- If the parents already have one child with a severe birth defect related to a genetic problem.
These and other issues signal potential problems that could occur in the pregnancy, necessitating the doctor recommend genetic testing. Genetic testing continues to improve our ability to diagnose and treat illness. But these tests still have their limits. For example, they can tell you about the potential for developing a genetic disorder in a growing fetus but sometimes cannot definitively guarantee that the disorder will manifest in the infant. Too, people with high-risk genes may be able to make lifestyle changes to lessen the impact of potential illness.
What Are the Types of Genetic Tests Available?
Genetic tests performed during pregnancy can provide valuable information to a parent or parents and their doctor about the health of the fetus and the pregnant woman. If at any time, problems are detected, additional diagnostic testing should be conducted to confirm the results.
Some of the types of genetic testing include:
- Amniocentesis is a type of diagnostic testing that occurs between 15 to 20 weeks of pregnancy. In this procedure, the doctor inserts a hollow needle into the pregnant woman’s abdomen to sample a tiny amount of amniotic fluid from around the developing fetus. Doctors can check that fluid for genetic issues such as Down syndrome or spina bifida, check the child’s sex, or even tell how far the baby’s lungs have developed.
- Chorionic villus sampling (CVS) occurs between 10 to 12 weeks of pregnancy. In this procedure, the doctor removes a small piece of the placenta. That tissue sample can be checked for genetic issues in the growing fetus. This test can detect the presence of a chromosomal condition, such as Down syndrome or genetic conditions such as cystic fibrosis.
- Maternal serum quad screening is a blood test that can occur between weeks 15 and 21 of the pregnancy. Like the other tests, it looks for chromosomal or genetic problems.
- Prenatal cell-free DNA screening (cfDNA) is a blood test for pregnant women conducted after 10 weeks. It can detect chromosome problems in the fetus.
- Sequential integrated screening occurs between 10 to 13 weeks of pregnancy. This procedure uses a mix of blood testing and an ultrasound to look for genetic issues or chromosome disorders. It is called sequential because it is often conducted once during the first trimester and again in the second. The second test should occur before the 22nd week of pregnancy. The first and second tests are typically combined into a single screening result.
- Ultrasound testing can occur around week 20. The clinical technician uses a machine to make images of the baby by using sound waves. From these images, the doctor can diagnose heart and kidney problems, cleft palate, or other birth defects.
It should be noted that deciding to have these tests is a personal choice for each woman and her partner, family, or another support system. There is no right or wrong answer.
Your obstetrician or other healthcare provider will discuss what these screening test results mean and help you decide your next steps.
How Can Your Doctor Help with Genetic Testing During Pregnancy?
If you’re considering pregnancy, you may have mixed feelings. On the one hand, it’s exciting to welcome a new baby, but on the other, you may have worries about their health, especially if you’re at risk for genetic disorders.
Advanced Obstetrics & Gynecology of Lake County is here to help you and your family make informed decisions about your health. We offer a highly experienced team of clinical care providers in a personalized, supportive environment devoted to serving our patients.
In addition to the information provided by our expert clinical staff, we offer this page as an extra resource to help you understand genetic testing. We know you have questions; please don’t hesitate to reach out to us for further assistance.