How can you do a DNA test before the baby is born, and is it safe? Your doctor might suggest genetic screening while you’re pregnant, during one of your checkups, for various reasons. DNA testing while you’re pregnant doesn’t immediately mean that there’s a definite problem with your baby.
Instead, your doctor may just want to ensure that everything is okay with you and your baby, and that everything is progressing smoothly with your pregnancy. The suggested tests while you’re pregnant may also be a follow-up on a result from a previous screening test that you had which showed some cause for concern.
The following are the common screenings and DNA tests that are conducted while you’re pregnant, and why:
DNA Test Before the Baby is Born: First Trimester Screenings
When you become pregnant, a doctor may suggest having a genetic test to screen for the risk of a medical problem. Genetic testing during pregnancy in the first trimester is generally completely safe.
Below are the most common screenings and DNA tests while pregnancy in the first trimester:
- Cell-Free Fetal DNA Testing: It is also called Non-Invasive Prenatal testing (NIPT) where small fragments of your baby’s DNA could end up in your own blood. After 10 weeks, your ob-gyn takes a blood sample to test the baby’s DNA i.e., extracted from your blood sample for signs of these common genetic anomalies: Down syndrome, Trisomy 13 and 18, and issues with sex chromosomes (X or Y).
- Sequential Screening: It is also called First Trimester Screening where it combines blood and ultrasound to look for the risk of spina bifida and brain problems, Down syndrome, and trisomy 18. This test is conducted between 10 and 13 weeks of pregnancy.
- Integrated Screening: This test on your unborn baby has the same procedure as sequential screening, and it tests for the same risks. However, this is more comprehensive because you get the initial test at 12 weeks and the follow-up in the second trimester.
Second Trimester: How Can You Do a DNA Test Before the Baby is Born in Your Second Trimester?
In the second trimester, there are some tests that are commonly screened. Here are the tests your doctor may recommend in the second trimester of pregnancy:
- AFP Test: This test screens the alpha-fetoprotein level of a pregnant woman’s blood to assess the risk of neural tube defects or Down syndrome. This is conducted between 15 and 21 weeks.
If Down syndrome runs in your family, you’re more likely to be recommended to get this test done. Typically your prenatal doctor would have a good reason for ordering this test.
- Part 2 Integrated Screening: If you opt for this test in the first trimester, another blood test is done when you’re at 16 to 18 weeks of gestation. This is part two of the screening.
- Maternal Serum Quadruple Screen: known as the Quad Screen, this is another blood test that looks for proteins to check if your baby has a higher risk of spine or brain problems, Down syndrome, and trisomy 18. This is done between 15 and 21 weeks of gestation.
- Non-Invasive Ultrasound: This is a common tool in screening for fetal genetic syndromes. At 18 to 20 weeks, a sonographer uses imaging to take scans of your baby’s development. The doctor will look out for defects that could indicate Triploidy, Turner Syndrome, etc.
Diagnostic DNA Testing: Slightly More Invasive DNA Test that can be done Before the Baby is Born
There are two more invasive tests that can be done while you’re pregnant. These slightly more invasive tests are examples of a DNA test before the baby is born that aren’t considered quite as safe as the rest since there is a ≤ 1% risk of miscarriage associated with these tests.
Amniocentesis and Chorionic Villus Sampling (CVS) are more definitive diagnostic tests that your doctor may recommend if your results turn positive for any of the above screenings. These two tests confirm possible defects and genetic disorders. This type of DNA test done before the baby is born is a lot more accurate than simple blood screens, since the doctor will draw samples directly from the amniotic fluid for amniocentesis or placenta sample for CVS. Note that these tests identify potential genetic problems in your baby, but they do not provide any information on the severity of the condition.
How can you do a DNA test before the baby is born safely? The thing is, these tests are usually safe, but they carry with them some risks, and that’s why doctors won’t order these tests unless they have very valid reasons to do so.
Since both tests are invasive, using a long, fine needle guided by ultrasound, there’s a small risk of miscarriage or issues like bleeding, cramping, or infection. The CVS test takes a small sample of the placenta between 10 and 13 weeks. Meanwhile, amniocentesis is a test where amniotic fluid surrounding the baby in the womb is collected.. The lab then checks the fluid for cells and proteins to confirm genetic anomalies. It is the safest between 15 and 20 weeks. The advantage of CVS over the amnio is that it can be done earlier in the pregnancy.
If you have any questions or concerns about DNA testing while you’re pregnant, the best resource is your doctor. Talk to your ob-gyn about the pros and cons, especially what the test results could mean for you and your baby. And if your baby is found at risk, your doctor could request more specific tests and prepare you thoroughly at the time of birth.
Consider Non-Invasive DNA Testing Before You’re Pregnant for Family Planning Purposes
Before you even get pregnant, it would be the best time to do a DNA test for the sake of your unborn baby’s health. This simple at home DNA test involves a non-invasive cheek swab to check for genetic mutations you could pass to your child, and this safe DNA test is called the CircleDNA Family Planning DNA test.
You and your partner could both get the CircleDNA Family Planning DNA test done, to find out if you’re both carriers for the same gene or the genetic mutation, which increases the risk for your unborn child. This would encourage you to perhaps get some testing done while pregnant.
When you get your test results back from this DNA test, even if only one of you is a carrier of a genetic mutation, this still extends some risk to your unborn child. This information will be useful when discussing family planning with your doctor.
Genetic carrier screening tests such as the non-invasive one from CircleDNA could look at both the father’s and mother’s genes. Test results show the chances of their offspring or child inheriting a genetic disorder like sickle cell disease, cystic fibrosis, Tay Sachs disease, etc. You could unknowingly be a carrier, because carriers don’t have symptoms. However, being a carrier could impact your unborn baby.
DNA testing while pregnant, and having your partner undergo the same screening, provides comprehensive information because your baby’s genetic makeup comes from both mother and father. Remember that test reports will share if you or your partner carry any genetic mutations and the chances of you passing them to your children. Note that if both mother and father carry the same gene mutation or different genetic mutation in the same gene, the baby will have a 25% chance of being affected by the condition and can experience symptoms (even if the parents don’t show any symptoms at all). For example, if you’re a confirmed carrier of a debilitating disease like Pompe Disease, you can undergo in vitro fertilization (IVF) and opt for embryonic screening i.e., also called as preimplantation genetic testing (PGT) to ensure your future child’s quality of life by selecting the embryo which doesn’t carry the genetic mutation either of the parent carries. This is crucial information to be aware of when it comes to family planning, and protecting your future child’s health.
Get Screenings Done if You Have a Potentially Higher Genetic Risk
Certain ethnic groups are more likely to be carriers of specific genetic health disorders. For example, Eastern Europeans of Jewish descent are prone to Tay-Sachs and cystic fibrosis while Africans and South East Asians are predisposed to sickle cell disease. Speak to your doctor about these common genetic disorders and talk about the steps you can take if you’re in a high-risk category, especially if you’re concerned about the chances of passing on the problems to your future child. Including DNA testing with family planning is the best way you can take care of your future baby even before you conceive.
Empower Yourself to Make the Safest Choice for You and Your Baby
Understanding the potential genetic health conditions your future child could inherit from you and your partner can help seek to learn about early testing and treatment. You can also use the information from the DNA tests to take preventive measures. For example, if your test indicates elevated risk or a strong risk of age-related macular degeneration (AMD), you can wear sunglasses outside, blue-light-blocking glasses while using the computer, and eat antioxidant-rich foods to protect your eyesight, while encouraging your kids to do the same. More importantly, you can share the reports with your doctor to assess if further testing may help. You can learn a lot about your family’s biological health history from a DNA test to determine if you’re at risk and what kinds of precautions you and your offspring can take.
References:
- Common Testing When Pregnant (Johns Hopkins) https://www.hopkinsmedicine.org/health/wellness-and-prevention/common-tests-during-pregnancy
- The Role of Ultrasound in Diagnosis of Fetal Genetic Syndromes https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4079588/
