Prenatal Genetic Testing 101
What is genetic testing in pregnancy?
Genetic testing during pregnancy can give you information about whether your baby has certain genetic disorders. Genetic disorders occur when there is missing, extra, or mutated genetic information – these alterations can happen at the time of conception or may be inherited from one or both parents. Check out our video on the two most common types of genetic testing: Carrier Testing and Non-Invasive Prenatal Testing (NIPT).
At Oula, all genetic testing is optional – there are good medical reasons to pursue these tests, but we encourage you to make the decision that feels right to you. You should be aware that genetic testing sometimes adds out of pocket costs so you should discuss with your insurance company.
Carrier Testing
What is Carrier Testing?
Carrier testing is a type of genetic test that looks for recessive gene disorders in one or both parents. It is common to “carry” one of these genes, but in order for your child to have one of these disorders, both you and your partner or sperm donor would need to carry and pass the same recessive gene to your baby.
Because this test evaluates your genes rather than a particular pregnancy, it only needs to be done once in your life. So if you have already had carrier testing, you do not need to repeat it. Often, our patients will choose to test one partner, wait for results to see if that person is a carrier, and then test the partner or sperm donor to see if there is any overlap.
What kind of tests are available?
Our genetic testing partner, LabCorp, offers a variety of carrier testing panels for you to choose from.
- You could test a small set of the most common recessive gene disorders (such as cystic fibrosis, spinal muscular atrophy, fragile X, or tay sachs).
- You could test for a list of disorders targeted to a particular ethnicity or background that you both share (for example, people with Ashkenazi jewish or African American heritage have higher incidence of certain recessive gene disorders).
- You could choose an “expanded panel” that would test you for over one hundred recessive gene disorders. We like to warn our patients that when we test for this many things, it is very likely that you will come back as a carrier for something but because many of the disorders are very rare, it is very unlikely that you and your partner will have any overlap.
- You could opt to skip this type of testing entirely!
How is the test done?
This test is done as a blood test or, in some cases, a saliva sample. The results take two to four weeks to come back. In most cases, if you are a “carrier” for one or more conditions, our next recommendation will be to refer your partner or sperm donor for testing. Your partner’s test will also take a few weeks to result. If you both carry the same gene for the same disorder, we will refer you to speak to a genetic counselor about next steps. If one partner is found to be a recessive gene carrier, but the other partner is not, then your children might also carry the recessive gene, but they will not be affected by the disorder.
Will my insurance cover this?
Insurance coverage varies for carrier testing. We recommend that you discuss coverage with your insurance carrier. You can also reach out to our testing partner, Labcorp, for more information about testing options and cost estimates.
Here are some details to guide your conversations with Labcorp and/or your insurance company:
- CPT code: 81443
- Labcorp cost estimator
Why would I choose this?
If you have any genetic conditions in your family or community, you might want to learn more. If you’re someone who “likes all the information”, this will definitely provide you with useful information about your genetic carrier status that you will have for the rest of your lifetime. Negative results can be reassuring. If partner results are available, they can be reassuring or helpful in gathering more information before making clinical decisions about your pregnancy care.
Why would I not choose this?
If your sperm or partner genetic testing is not available and therefore you are not able to get a full picture of the carrier risk to your pregnancy, that may cause unnecessary stress to your pregnancy. If you are someone who knows that you would not change the course of your pregnancy care, either diagnostic testing or termination of pregnancy, based on genetic information, then the results may not be useful as a screening tool.
NIPT
NIPT stands for Non-Invasive Prenatal Testing. It refers to a prenatal screening blood test we offer to evaluate some of your baby’s chromosomes when you are at least 10 weeks pregnant. It’s also the test that can tell you the baby’s sex ahead of the 20 week anatomy ultrasound, if you would like to know it.
How does this test work?
NIPT is done with blood drawn from the pregnant person. At a specialized genetics lab, they are able to tease out tiny fragments of fetal DNA that are floating in the pregnant person’s bloodstream. By evaluating this “fetal fraction” they are able to tell us if the baby has any issues with the chromosomes included in the test panel.
Which chromosomes are included?
This test checks whether your baby has any issues with chromosomes 13, 18, 21, or the X or Y sex chromosomes. This means we can also determine the sex of the baby from this test! This very sensitive screening test tells us about these chromosomes with 99% certainty. Because NIPT is a maternal blood draw, this test does not cause miscarriage or risk the pregnancy.
Are there other options to test for more things?
If you are interested in a deeper exploration of your baby’s genetic status, we would recommend that you consider diagnostic testing such as an amniocentesis (amnio) or chorionic villi sampling (CVS). You might have read in the media about “expanded” NIP testing which includes the option to screen for additional chromosomal abnormalities, microdeletions or duplications. Unfortunately this version of the NIPT is not considered reliable and therefore we would recommend diagnostic testing if you are interested in this deeper level of genetic information about your pregnancy.
What if I don’t want to know the sex of my baby?
We never release information about your baby’s sex without your permission. You can opt to have the test result exclude the fetal sex, or you can opt to have the sex reported but ask that we not share it with you unless you tell us you want to hear it. And, sure, we can share the sex of your baby to you in a sealed envelope in case you want to reveal that information in a special way.
What will happen if my NIPT comes back “high risk”?
In this case, we will send you for a consultation with a genetics counselor. You might opt to have a diagnostic test like an amniocentesis (amnio) or a chorionic villi sampling (CVS) as a follow-up. These procedures sample some genetic material from inside the pregnancy and can tell us with 100% certainty whether your baby has a chromosomal abnormality or other genetic issue.
If the “diagnostic” test is 100% certain, why don’t I just have that test?
Tests like amniocentesis or a chorionic villi sampling can, in rare cases, result in pregnancy loss. When we need these invasive tests, the risk is often worth the benefit, but we recommend that you do the non-invasive testing first. NIPT is an excellent test – it’s low risk & it’s reliable – and for most people it eliminates the need for the riskier diagnostic testing. If you have a known genetic history or a previous pregnancy affected by a genetic issue, you may opt to skip NIPT and go straight to diagnostic testing. We will discuss these options at your prenatal visit.
Why would I choose genetic screening?
If knowing that you were carrying a fetus with a chromosomal abnormality might make you consider terminating the pregnancy, this is the earliest test available. If you want to know the sex of the baby as early as possible, this is the path toward that information. If you’re someone who “likes all the information”, this will definitely provide you with useful information about your baby’s genetics. Carrier testing will highlight your carrier status – which is a test you only need to do once in your lifetime. If partner carrier results are available, they can be reassuring or helpful in gathering more information before making clinical decisions about your pregnancy care. In the case of both types of tests, negative results can be reassuring, and positive screening test results can help to inform your path toward diagnostic testing.
Why would I not choose this?
If knowing your fetus carries a chromosomal abnormality would not impact your decision to carry your pregnancy to term (or terminate) or if you’re comfortable waiting for genetics screening and assessment of normal fetal development until later in the pregnancy through other screening tests. If you consider yourself low risk for chromosomal abnormalities based on your age and other risk factors, you may prefer to opt-out of optional screening tests.
Will my insurance cover this?
Insurance coverage varies for NIPT. We recommend that you discuss coverage with your insurance carrier.
Here are some details to guide your conversations with Labcorp and/or your insurance company:
- CPT code: 81420
- Labcorp cost estimator
In addition, you may want to ask your insurance company if they will cover NIPT and the nuchal translucency ultrasound. These two types of tests include some overlap as methods for screening your pregnancy for chromosomal abnormalities or other syndromes. While there are excellent medical reasons to have both tests, we cannot guarantee that both tests will be covered by your insurance.
Nuchal Translucency (NT)
What is the NT test?
The Nuchal Translucency is a specialized ultrasound done between 11-13 weeks in your pregnancy. During the ultrasound the sonographer and Maternal Fetal Medicine doctor will take an overall look at your baby, measure the “crown-rump” length (top of the head to the bottom of the tailbone) to confirm that your due date is correct, and they will pay particularly close attention to an area at the back of the baby’s neck called the nuchal fold or nuchal translucency (NT).
What do the results mean?
Abnormal measurements of the nuchal translucency (NT) can be soft markers for cardiac defects and chromosomal abnormalities and other syndromes, but the measurement is not 100% diagnostic. If your baby has an abnormal NT measurement, our team will take a broader look at your prenatal testing to see if there are any other reasons for concern. We will recommend that you see a genetic counselor to discuss the finding, and to make a plan for follow-up testing.
Why would I choose this?
If you are opting to have a dating and viability ultrasound, this test is easily incorporated into that already standard of care visit at a partner testing unit. If you want all possible information about chromosomal and genetic abnormalities as soon as possible, this gives you additional information that may reassure you about the well being of your fetus’ development during the first trimester.
Why would I not choose this?
If knowing your fetus carries a chromosomal abnormality would not impact your decision to carry your pregnancy to term (or terminate) or if you’re comfortable waiting for genetics screening and assessment of normal fetal development until later in the pregnancy through other screening tests. If you opted in for the NIPT test and feel reassured by that information and had an office ultrasound to confirm your dating, you may prefer to limit ultrasound exposure. If you consider yourself low risk for chromosomal abnormalities based on your age and other risk factors, you may prefer to opt-out of optional screening tests.
AFP
What is the AFP Test?
AFP is a protein made by the growing baby that can be found in a pregnant person’s blood or amniotic fluid. The MSAFP (Maternal Serum Alpha- FetoProtein) is collected through a blood draw at our office. The test is commonly covered by insurance as part of standard pregnancy screening.
Why do we offer AFP screening?
AFP is a screening test to evaluate your baby for a type of birth defect called a neural tube defect. The neural tube is what forms the brain, spine and spinal cord of the baby. Neural tube defects happen when the neural tube does not close correctly and can lead to conditions like spina bifida.
When can I get the AFP?
Your blood work can be drawn between 15 weeks and 22 weeks and 6 days. For your convenience, you may choose to have the blood drawn during your 16 week in-person visit at Oula.
What do the results mean?
The AFP test is a screening test and the results will fall into “Low Risk” or “High Risk”. If your AFP blood work shows an elevated risk for neural tube defect, you will be referred for an ultrasound.
Why would I do this?
This is the final bloodwork offering for genetic testing, if you are “all in” on genetic testing, this is the last piece of the puzzle in addition to your 16 week and 20 week anatomy ultrasounds.
Why would I not do this?
If you feel reassured by earlier genetic testing that you opted in for, if you are comfortable with ultrasound screening as a tool for identifying abnormalities or if you prefer a “less is more” approach to your pregnancy testing journey, you may opt out of this test.