45. Prenatal Genetic Screening Tests: Testing Options and Important Details

Are you wondering about your options for prenatal genetic testing and what information they will actually give you?

In this episode we talk about…

• Understanding genetic screening versus diagnostic tests…
• When and why genetic tests are recommended…
• Types of tests including NIPT, first trimester screen, quad screen, and more…
• Factors that influence the decision to test or not to…
• …and so much more!

If you want to know what options you have for genetic screening and need help deciding what to do, definitely tune in to this one! 

And for more pregnancy and birth support, save your seat in the virtual pregnancy support group coming up!

>> Join the Virtual Pregnancy Support Group starting February 21st<<  

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Welcome, friends! I am Beth, a certified nurse midwife, doula, and childbirth educator. My philosophy is rooted in autonomy, informed decision making, and positive mindset to help expecting parents plan for a beautiful, stress-free birth. I am here to provide value to YOU through tips and practical advice, either to guide you through pregnancy or to help you prepare for childbirth, postpartum and beyond. There’s no fluff here - only info that adds to your positive experience and saves you stress and uncertainty.

Transcript

Hello and welcome back to episode 45 of Your Birth Bestie podcast. Today, I am going to help clarify the differences between prenatal genetic testing options, the types that are offered, how they are performed or collected, what the time frame looks like to maximize accuracy of the results, and what goes into making the decision on whether you want to do these tests or if you’d rather pass. These are commonly asked questions in early pregnancy and it’s completely up to you whichever you decide, there is no right answer. So I think you’ll find this helpful if it’s something you’re considering and trying to better understand. 

If you have follow-up questions about your own personal circumstances, I’d love to hear from you over on Instagram @bethconnors_cnm so send me a message there and I’d love to chat. I also have recently opened enrollment into the virtual pregnancy support group starting mid-February, so that would be a great space to bring your questions and hear my thoughts and other mom’s experiences as well. We will be talking about topics related to pregnancy and birth options and interventions, mindset and pain coping techniques, birth planning, postpartum, breastfeeding, and lots more! We will have a topic each week, but it will mostly be a space to get all of your questions answered either LIVE on Zoom, or submitting your question beforehand and watching the replay if you are unable to make it to the call that week. 

I’m excited to start in a few weeks and to learn more about the bonuses included like access to fearless birth academy and my evidence-based resource library, head over to bethconnors.com/groupsupport and you can save you spot and join me and a small group of like-minded women in a few weeks!

Let’s first talk about what is genetic screening and how they are different from diagnostic tests? So, genetic screening is a method used during pregnancy to identify potential genetic disorders or conditions in your developing baby. These may include conditions like Down syndrome, Trisomy 18, and Trisomy 13, among other things. The screening process may also identify the risk of specific genetic disorders based on family history or maternal age.

Unlike diagnostic tests that provide an actual definitive diagnosis, genetic screening gives you the likelihood of your baby having certain conditions. It's important to remember that screening is a proactive step taken to understand the risk rather than confirm a diagnosis. So basically, you won’t get a for sure diagnosis from a genetic screening test, but rather the odds of whether or not your baby will be born with a genetic condition is the purpose of the test.

Diagnostic tests, on the other hand, are done when there's a specific concern or a higher risk identified through those initial screenings. So diagnostic tests are the next step after a positive screening test or high-likelihood of a genetic condition being present. These tests, such as amniocentesis or chorionic villus sampling (CVS), provide more information about the possible genetic abnormalities. So, in essence, screening acts as an initial filter, helping healthcare providers determine if further diagnostic testing would be recommended or not. The amniocenteis and chorionic villus sampling that I mentioned as the diagnostic tests, those are also more invasive procedures. Rather than a blood test or an ultrasound in the screening tests, which we’ll go into the details of each more in a minute, an amniocentesis involves sampling the amniotic fluid around your baby using a needle, and CVS also in the same way takes a bit of the placental cells to test. So this is why the tests aren’t performed unless there is a good reason for concern.

Based on where you’re at in your pregnancy right now, you might be wondering when certain genetic tests are recommended. There are genetic screening offered in the first and second trimesters, with the ideal time depending on factors such as the type of screening, which we’ll talk about in a minute, and individual circumstances. Maternal age is one factor because there is an increased risk of chromosomal abnormalities for women becoming pregnant after the age of 35. Also, a personal or family history of genetic disorders or a previous child with a genetic condition may elevate the risk. 

Either way, these screenings are not mandatory, and the decision to choose genetic screening is a very personal one. Expecting parents should discuss these factors with their healthcare provider, considering their values, beliefs, and the potential impact of the information on their pregnancy journey before making a decision.

So, now let’s go into the different types of genetic screenings available and a more detailed look at when they can be accurately done.

There is non-invasive prenatal testing, or NIPT, that can be done in the first trimester, as early as 10 weeks, but can also be at any time, there is no rush there. NIPT is also known as cell-free DNA testing if you’ve heard of it called that, and it’s a highly accurate screening test that looks at fetal DNA in mom’s blood. The chromosomal abnormalities tested for include Down syndrome (Trisomy 21), Edwards syndrome (Trisomoy 18), and Patau syndrome (Trisomy 13). You can also determine the gender of your baby with this test, but it is not the only purpose for NIPT. 

If you are considering early genetic screening, NIPT is an option and your clinic may do the Harmony Test or Materniti21, both are cell-free DNA tests, these are just different names for the same thing. One side note, is before going ahead with genetic screening, give your insurance carrier a call and see what your member benefits are in regard to genetic screening in pregnancy. They will be able to tell you what is covered and what isn’t. I’ve had moms with a very large, unexpected $1,000 bill from a test that they only got because they thought was covered. Some parents only want to find out the gender and use the NIPT as a way to do this, but another alternative that isn’t through your doctor’s office is the SneakPeek test that you can do at home really easily. That is about $75 to find out the gender as early as 6 weeks, so there are options there as well if this is something you’re interested in. I have done SneakPeek with all my babies and we’re 3 for 3 so far, all girls!

But back to the NIPT tests, a blood sample is taken from mom and they are looking at DNA from the fetus and placenta that circulate in mom’s blood. This is why it’s non-invasive, because there is no harm to mom or baby. This is the major advantage over the diagnostic tests I mentioned before that do both carry a small risk of miscarriage.

Accuracy of non-invasive fetal DNA testing has been proven to be very accurate with a >99.5% detection rate. As a result, it has replaced genetic amniocentesis for most patients who previously would have chosen that option, and now also gives the same high level of reassurance to lower risk patients without a risk to the pregnancy. And then as a side benefit, it can determine fetal sex with >99% accuracy.

The next type of genetic screen is called the first trimester screen, including a blood test like I just talked about, but it includes an ultrasound as well. And this is done between 11 weeks, 0 days, and 13 weeks, 6 days. The blood test measures specific markers, and the ultrasound measures the nuchal translucency (NT) thickness in the back of the fetal neck. This combined information helps estimate the risk of conditions like Down syndrome and can reduce the number of patients being recommended further invasive tests.

Some moms may want to have their 12 week nuchal scan and non-invasive fetal DNA test done on the same day. However, because NIPT testing can be performed as early as 10 weeks, other patients may choose to have the blood test performed at that time, and then return for a nuchal scan or combined screen at 12-13 weeks. 

And then the last type of screen can be done in the second trimester, so a little bit later between 15 weeks, 0 days, and 20 weeks, 6 days. This test is called the quad screen and is a blood test that assesses the risk of neural tube defects like spina bifida and chromosomal abnormalities. The test is looking for alpha-fetoprotein (AFP), which when elevated can indicate a greater risk for conditions like spina bifida or when lower, a marker for Down syndrome. 

So now that you have information about the options and more details, I did want to briefly mention what can go into the decision on whether to go ahead with genetic screening or decline it. This is absolutely a personal choice that involves careful consideration of various factors and to make an informed decision, it can be helpful to have an open and honest discussions with your healthcare provider. Factors to consider include individual values, beliefs, and the potential impact of the information on your decision-making. You’ll want to weigh the benefits of having information early in your pregnancy and detecting a potential concern and preparation against any potential emotional, psychological, or physical implications that might have. Some people the test would change how they progress through their pregnancy and others it wouldn’t so this is an important distinction to make before moving forward.

There are also practical aspects that can also be taken into account. Considerations may include the cost of the screening, whether insurance covers the expenses, and if financial assistance programs are available. Also, ethical considerations may come up, prompting parents to reflect on their stance regarding reproductive choices and the potential outcomes of the screening results. Each family's situation is unique, and these conversations with healthcare providers can provide clarity on the available options, empowering parents to make decisions aligned with their values and circumstances.

When contemplating the emotional and psychological aspects of genetic screening, individuals should reflect on how they would handle different outcomes. Some may find comfort in knowing early on about potential challenges, allowing for better preparation and support. On the other hand, for some, the uncertainty and the possibility of receiving distressing news might cause anxiety and impact the enjoyment of the pregnancy. It's really important to consider personal coping mechanisms, emotional resilience, and the availability of support systems. Ultimately, understanding one's emotional readiness and the potential impact on the pregnancy experience is fundamental in making a decision.

Thank you so much for tuning in to this episode all about genetic screening. I hope you found this helpful and maybe thought provoking on the choices that you have in your own pregnancy. I would love to talk through all things pregnancy, labor and birth prep, and support through posptartum in my upcoming virtual support group, so if you haven’t checked it out already, here’s your official invite to click on the link in the show notes, bethconnors.com/groupsupport, look through the program and reach out with any questions about getting started. I am so excited for you to experience the full-excitement and potential of your best pregnancy and birth experience, having each choice be your own and one you feel informed and confident about. I will be back here next Tuesday, so stay tuned for the next episode. Have a great week!