While pregnant, you have many options for prenatal care available. One decision you will need to consider is whether to have prenatal genetic testing (genetic testing during pregnancy). You may wonder, “Can I get a DNA test while pregnant?” Naturally, the next question you may ask is where to get a DNA test during pregnancy.
We will answer those questions and provide you with introductory information about prenatal genetic testing – what it is, what your options are, and considerations when making decisions about genetic testing during pregnancy. You will learn basic information to help you have informed conversations about genetic testing with your obstetrician or genetic testing doctor.
Can I Get a DNA Test While Pregnant?
Yes! DNA testing is available while pregnant. A common reason for DNA testing while pregnant is to determine paternity. Your doctor can determine paternity by taking a sample of the mother’s blood (containing the maternal DNA and small amounts of DNA from the fetus) and a sample of the assumed father’s DNA via tissue sample. You have many options for getting a DNA test, including home test kits or testing at a medical provider or lab. When considering where to get a DNA test, it is important to note that at-home tests are typically not advised for legal paternity.
Genetic Testing During Pregnancy: An Overview
Beyond testing DNA for paternity, genetic testing in pregnancy can be completed to identify the presence or absence of inherited disorders. Prenatal genetic testing is broken into two distinct categories – genetic screening and diagnostic testing.
- Genetic screening is noninvasive and presents little to no risk to the fetus. However, prenatal screening tests can only determine if there is a likelihood of a genetic abnormality. Genetic screening does not provide a definitive diagnosis.
- Diagnostic testing is the only way to get a definitive diagnosis. However, diagnostic testing comes with risks to the fetus. Therefore, diagnostic testing is generally only recommended when prenatal screening tests indicate a likelihood of an abnormality or if other risk factors exist, such as family history or age.
What Conditions can be Identified by Prenatal Genetic Testing?
Genetic testing during pregnancy can identify the presence or absence of conditions caused by changes in a person’s genes or chromosomes. Conditions include those caused by missing or extra chromosomes, such as Down Syndrome. Conditions also include those caused by mutations in genes, such as those seen in cystic fibrosis and sickle cell disease.
Types of Prenatal Screening Tests
As noted above, prenatal genetic screening can indicate if your baby is at risk of having certain genetic abnormalities, but it is not definitive. Prenatal screening tests are generally non-invasive with no risk of miscarriage. Genetic screening can include any or all of the following:
- Carrier testing: Carrier testing is used to determine if you and your partner carry the gene(s) for certain inherited disorders. Carrier testing is completed on the parents using blood or tissue samples. Carrier testing can be done before conception when a couple is considering starting a family or can be done while pregnant.
- First-trimester screening: Completed during the first 12 weeks of pregnancy, these tests are conducted on the pregnant women’s blood and by reviewing ultrasound exams. Blood tests measure the levels of substances that may indicate the presence of inherited conditions. Ultrasound exams may show defects of the heart, abdomen, brain or spine, and facial features characteristic of certain genetic conditions.
- Second-trimester screening: Again, testing of the mother’s blood is completed along with ultrasound examinations. The “quad” blood test measures levels of four substances in the mother’s blood. Ultrasound images are reviewed for major physical defects characteristic of certain conditions.
- Cell-free DNA testing: During pregnancy, a small amount of DNA from the fetus is released into the pregnant woman’s bloodstream. Screening of this cell-free DNA in the mother’s bloodstream can determine the sex of the fetus, the rhesus (Rh) blood type, and chromosomal abnormalities found in conditions such as Down Syndrome.
What are the Possible Outcomes of Prenatal Screening Tests?
Negative results from screenings mean there is a low risk of the inherited or chromosomal disorder tested for. Although there still exists a possibility of genetic conditions, some parents feel comforted and experience less anxiety after prenatal screening tests have been completed with negative results.
Screening could show a higher risk of genetic disorders than the general population. This means that your child may have a genetic condition. Genetic screening will not show a definitive diagnosis.
- Some parents will stop genetic testing during pregnancy at this point and wait for the pregnancy to come to term. They may use this time to educate themselves on the condition(s) that their child is at risk for and learn about available treatment options should their child be born with the condition.
- Some parents will choose to have diagnostic testing performed to determine with greater accuracy the likelihood of their child having the genetic condition. For some parents, knowing this information helps them plan for treatment for their child to ensure the best possible outcome.
Types of Diagnostic Genetic Testing
Diagnostic genetic testing can be done if prenatal genetic screening indicates a problem or if you have other risk factors like age, family history, certain environmental exposures, etc. Diagnostic testing is more invasive than screening, and some carry a slight risk of miscarriage. However, diagnostic testing is the only way to get a definitive diagnosis before birth. Diagnostic testing is completed on fetus or placenta cells received by amniocentesis or chorionic villus sampling (CVS).
- In amniocentesis, ultrasound images are used to help guide a very thin needle to withdraw a small amount of amniotic fluid. That fluid is then tested in a lab.
- Chorionic villus sampling (CVS) is completed by taking a sample of tissue from the placenta. The risk of miscarriage after CVS is slightly higher than in amniocentesis, but CVS can be performed earlier in the pregnancy.
What are the Possible Outcomes of Diagnostic Testing?
Negative results mean that the fetus does not have the particular disorder screened for. Parents with risk factors for passing on genetic conditions may feel relieved after negative diagnostic tests.
Positive results confirm that the fetus has the condition tested for. Your obstetrician will explain positive results in detail and provide information about your options. You may choose to consult with a specialist in the disorder to understand treatment options and prognosis. You may also meet with a social worker who can provide you with more information, answer your questions, and link you to support groups. Additional testing may be recommended to learn more about the development of the fetus.
In rare cases, if life expectancy is significantly shortened and treatments are not available for the specific condition, some parents consider termination of the pregnancy. This is a very personal decision that should be made only after definitive diagnostic testing has been completed and after consultation with experts in the condition identified.
Is Genetic Testing Right for You?
Prenatal genetic testing is optional, and the decision to have genetic testing while pregnant or before conception is based on personal belief systems. When deciding if you wish to pursue carrier testing, prenatal screening, or diagnostic testing, it is important to understand the limitations, the risks, and the timeframes for the availability of each test.
There is no right or wrong answer to the question of having genetic testing while pregnant. Some parents choose not to have any genetic testing, while some choose only specific prenatal screening, and others have extensive diagnostic testing. At Advanced OBGYN Institute, we are here to support your decisions related to genetic testing by first providing you with the information needed to make decisions.
Has this article helped you understand your options for prenatal genetic testing? If so, feel free to share this article with others on social media. We at Advanced OBGYN Institute look forward to continuing this discussion about genetic testing and answering any questions you still have at your next prenatal appointment.
