Prenatal Diagnosis: Ultrasound & Genetic Testing

Podcast Transcript

Erica Newlin, MD:

Welcome to OB/GYN Time, a Cleveland Clinic podcast covering all things obstetrics and gynecology. These podcast episodes are intended to help you better understand your health, leaving you feeling empowered to live your best. We hope you enjoy today's episode.

Hi everyone. I'm your host, Dr. Erica Newlin. Welcome to Ob/Gyn Time. During this season, we are focusing on topics related to pregnancy and obstetric concerns.  On this episode, I'd like to welcome doctor Courtney Stephenson and Marissa Coleridge who will be talking with me about ultrasound and genetic testing. Dr. Stephenson, Marissa, thanks so much for joining me on the podcast.

Courtney Stephenson, DO:

Thank you for having us, Erica.

Marissa Coleridge, MS, CGC:

Thank you so much.

Erica Newlin, MD:

Can you each tell us a little more about your role in the Cleveland Clinic and about your background? Dr. Stephenson, you can start.

Courtney Stephenson, DO:

Thank you, Erica. My role in the Cleveland Clinic is Director of Fetoscopic Intervention. I'm a maternal fetal medicine specialist who focuses on prenatal diagnosis and ultrasound and procedures for fetuses while in utero.

Erica Newlin, MD:

And Marissa.

Marissa Coleridge, MS, CGC:

Thank you so much for having us on today. So I am one of the prenatal genetic counselors here at the Cleveland Clinic. I'm the Director of Prenatal Genetic Counseling here and for our fetal care center as well. And a genetic counselor is a specialist who is trained specifically in counseling as well as genetics. And our roles are very subspecialized. And so there's genetic counselors specific to oncology as well as pediatrics, prenatal, cardiovascular, and, and my specialty is prenatal and preconception genetics. And so looking forward to having this discussion today.

Erica Newlin, MD:

For sure. I know when I’m in the office and put in the genetic counseling referral, there are a lot of different options. But for today, let's focus on prenatal genetic testing. Can you tell us when someone should plan to see a genetic counselor maybe prior to getting pregnant?

Marissa Coleridge, MS, CGC:

Yeah, absolutely. So I always talk to patients about like, wow, that's great. You're so on the ball. And of course we can see anybody throughout their fertility journey, either prior to pregnancy or during their pregnancy, patients that want to have those discussions prior to conception. We talk a lot about family history, their personal history and their partner's history as well. And you know, we do have patients that say like, oh, I'm adopted. I don't know my family history. And that's okay because they have, you know, say they're 22, we have 22 years of data on them, you know, which is great.

But we talk a lot about what is in their family history medically as well as exposure-wise. And then also thinking about genetic testing. Is there any risk with regard to things that are called autosomal recessive conditions, things that parents could be potentially carriers of. And we think about kind of what you might hear about common conditions like for example, sickle cell disease or like cystic fibrosis and, and we talk about those kind of things and doing blood work as far as that goes. Those are definitely optional. Those are things that people may want to pursue.

Courtney Stephenson, DO:

We work closely with the genetic counselors. They're a vital part of our practice. I appreciate them quite a lot since they can also discuss fetal anomalies or ultrasound findings, but in a different kind of voice that maybe the patient understands better than physician.

They are extremely knowledgeable and we work hand in hand together. If there is testing done, they can help us decide what the best tests are and whether screening or invasive tests are applicable. And so we make all those decisions together with the patient.

It's a joint decision making process where, when the patient's the center of the decision making and we present them with the information that's relative to their situation and we spend a lot of time getting to know our patients and we enjoy that quite a bit.

Erica Newlin, MD:

Perfect. And then again, focusing on preconception concerns. Could you touch upon what kind of genetic testing is available for people and what people might want to consider prior to getting pregnant?

Marissa Coleridge, MS, CGC:

Thanks. Yeah, absolutely. So a lot of times we talk about carrier screening and the size of those panels is they can be very large kind of carrier screening blood test panels or smaller ones depending on how much information somebody wants to learn. So we talk about what kind of conditions are on those panels and what's, if anything in addition is in the family history that could be pertinent or not in the family history.

Erica Newlin, MD:

Are there certain high-risk populations that you would recommend always doing carrier screening or at least highly considering carrier screening?

Marissa Coleridge, MS, CGC:

Part of my answer is yes, certain ethnicities do have a higher risk, but that is kind of starting to change. And so we offer kind of this pan-ethnic approach of genetic testing, a kind of a one-stop shop to everybody. So I would say, really genetic screening should be offered to everybody, all comers. And that's kind of what the guidelines tell us from our governing bodies, the American College of Medical Genetics and the American College of OB GYN. Groups that kind of help us to make sure that we're doing the right thing by patients.

Erica Newlin, MD:

Perfect. That's a great way of thinking about it. And to that point, you mentioned that there are a lot of variations in the carrier panels as far as how much things test for. Should people opt for the widest panel? Is more information beneficial versus how do you decide which carrier panel to order.

Marissa Coleridge, MS, CGC:

That's such a great question and it's something we all, I think Dr. Stephenson can, can weigh in, but it's something we talk about a lot in the office. Some panels are like 600 diseases plus. They're super big versus some other panels are like 14 diseases. And so there's really wide variation. And so, you know, I think the statement of big isn't always better is something for us to kind of think about.

Some of the really wide panels have conditions on it that don't always result in something physical or mental or really something that's going to be potentially meaningful for parents. And so we talk about that with patients and families to say like, okay, this is what these large panels could tell us. Would you want to know everything or would that information potentially make you more anxious; versus middle of the road kind of panel versus tiny panel and how much would you want to know? And everybody feels differently. Some people say like, oh gosh, that would really make me anxious, versus I am an information seeker.

You know, so really there's not a one-size-fits-all kind of answer to that question.

Erica Newlin, MD:

For sure. And are these tests usually covered by insurance?

Marissa Coleridge, MS, CGC:

Most of the time, yes. But you know how insurance is these days. So thankfully, at least today, most of these third-party labs, genetic testing labs kind of have bars that they have set.

So essentially, and that's part of our job as healthcare providers too, to help walk patients through this too because it's complex. Most of these labs that we work with basically will help us help patients say like, what is the estimated out of pocket cost? And then essentially have bars set to say like, if out of pocket cost is X, Y, and Z high, or if somebody has a really high deductible or X, Y, and Z, then the most they would pay would be, for example, some of the labs I'm thinking about would be like $250. So still costly but not thousands of dollars that a lot of the stigma around genetic testing could be.

Erica Newlin, MD:

And let's go down the road, say someone gets a carrier panel and they come back positive as a carrier for something, what do the next steps look like?

Marissa Coleridge, MS, CGC:

So it would depend on what the condition is and how it is inherited. So many genetic conditions are inherited in autosomal recessive manner, meaning both parents have to be carriers in order for us to be concerned or potentially a risk to have a, a pregnancy with whatever that disease is. And so the next step in that scenario would be to do the same test for that gene in the partner to see, what is our risk over here? Should we be concerned? And we would go through those potential risks, so that would be the next step. Versus if it's a condition that is on the X chromosome, then we don't need to screen the partner. We would say, okay, the risk is, potentially 50% in a future pregnancy. And we would cross that bridge and figure out what do we do next? What is the patient comfortable with? Do we think about, is IVF an option or do we think about doing testing during a future pregnancy? Everyone feels differently.

Erica Newlin, MD:

Yeah. And that brings me to my next question, which is what is the role of IVF if someone is a positive carrier for genetic disease?

Courtney Stephenson, DO:

IVF would, they would be able to look at the embryo before it's implanted and make sure that the genetic condition of concern is not present. It's still a screening test. Technically we still do the additional tests that are required like the ultrasounds and the cell-free DNA and things like that. But there are situations where if there's a gene of significant concern, patients could have their embryos tested and checked before they're implanted so that they're not at risk of carrying that condition in a pregnancy.

Erica Newlin, MD:

And shifting gears to test in pregnancy, let's talk about non-invasive prenatal testing or NIPT. What is it and what does it test for?

Marissa Coleridge, MS, CGC:

So non-invasive prenatal testing goes by the acronym N-I-P-T. Like you said, it can also be called different things just so everyone we're all talking, you know, apples to apples. Some labs call it N-I-P-S, non-invasive prenatal screening. It can also be called cell-free DNA - C-F-D-N-A. It's just the methodology. So however your healthcare team is calling it, it's all the same.

So essentially it's looking at a mixture of fetal DNA and placental DNA rolling around in the pregnant patient's blood when you're pregnant. And it basically is specific to certain chromosomal conditions, at least in 2025 that we can assess for.

I think potentially in the future we're going to get a lot better at it. We'll be able to screen for more things. Right now we can look for, it's assessing for down syndrome, which is also called Trisomy 21. And then other chromosomal conditions Trisomy 13, which is an extra chromosome 13 and Trisomy 18, an extra chromosome 18.

And then some, depending on which lab your healthcare team is working with, can assess for extra or missing sex chromosomes. The most common of which is also called Turner Syndrome or Monosomy X. And that is kind of very, you know, common. It's been around since the, you know, around 2012, 2013. And it's a screening test, meaning it's not absolute yes or no, but it's generally pretty good above 90%.

Erica Newlin, MD:

Great. So overall accuracy, are you usually telling people above 90% higher?

Marissa Coleridge, MS, CGC:

Yeah, it's, it's very specific to each condition and it's generally for the sex chromosomes above 90%, but for the other chromosomes it's a little bit better.

Erica Newlin, MD:

And do most insurances cover the NIPT?

Marissa Coleridge, MS, CGC:

They do.

Erica Newlin, MD:

Great.

Courtney Stephenson, DO:

ACOG in 2020 recommended that all pregnant women receive the NIPT screening test. That was a big shift. It's not to replace ultrasound, but in addition to, but every pregnant woman, whether they're 18 or 45 with whatever background, everybody's recommended to get the NIPT test or cell-free DNA screening.

Erica Newlin, MD:

Great. And I do have a lot of patients tell me, and maybe you've encountered this too, like, oh, I don't want to know the sex of the baby, I don't want to do an NIPT. Can you discuss why it still might be valuable?

Courtney Stephenson, DO:

Sure. The sex result on the cell-free screen is just a portion of the information that we get. The trisomy that Marissa discussed, trisomy 18, 13 21, those are still really important. And even if you don't have a family history of those conditions, they can happen like what we call de novo. Like for the first time in that one conception and the mother or the father or both parents or partners never had a history of down syndrome in their family. But then at that time when during conception they can be found that there is a trisomy.

So family history plays a role of course, but I hear a lot of patients also say, oh, we don't have that on our family. We don't need to do that blood test because that doesn't exist. That's true to an extent, but most of the patients, I would say like 80% of the patients or more, it's a new trisomy for that family and then it doesn't have to be inherited. It's just at the moment a conception that it occurs with the genetic exchange of information.

So it's really valuable to us as clinicians is very helpful to us because if we do see maybe a soft marker - and a soft marker is something that's not an abnormality, but it's a feature that we see in certain conditions and kind of raises our awareness that those conditions may exist in that fetus. Again, not an abnormality like a little bright spot that's not a structural abnormality, but it could raise your risk for down syndrome. But if you had already done the cell-free DNA screen and the result was low risk, that little bright spot is meaningless. We consider it clinically irrelevant or a normal variant.

So we use it quite a bit with markers and I think that really helps patients with their anxiety level. It's always hard if we find a marker and then we have to talk back to did you do the blood test? And they maybe they opted out, which is fine, but now they have the anxiety of not knowing the context of the bright spot, so to speak. So we use it a lot to give us context of some of the ultrasound findings that we have.

Erica Newlin, MD:

Sure. And similarly, many patients ask me what the point of genetic testing is if they're not planning on acting on it. How can genetic testing and diagnosis be helpful?

Courtney Stephenson, DO:

It's very helpful because conveniently genetic conditions have patterns in which the fetus will behave or we develop or grow and evolve that we can follow. So if there were diagnosis of a genetic condition, like I'll say trisomy 18, then we would know to look, get a detailed echocardiogram, look at the heart more closely, they have a higher risk of loss in the third trimester. Maybe we would increase testing, we might get other consults with NICU neonatology or other surgical consults.

So it's all about planning that delivery and also so that delivery takes place in the proper location. So information is very empowering and we respect, if people are interested in information, that's their choice. But we're here just to help them make these decisions in an informed way so that they're comfortable and that if it is something they want to know, we can help them map out the course of the pregnancy.

It could also help, and I've learned this over the years, if there are other like small children in the house and they're expecting a child with special needs while the mom, the patient is pregnant, it can help to describe what life might be like when the baby arrives so that the younger children can kind of mentally and emotionally adapt.

Erica Newlin, MD:

For sure. And I've also encouraged patients to get involved with parent groups. And have that support in place prior to delivery.

Courtney Stephenson, DO:

There's so many things you can have arranged and ready so that it's not like feeling chaos or at, at the time of getting the information. Especially with a new baby, which is already chaotic.

Marissa Coleridge, MS, CGC:

I think that's such a big question because I think there's so much discussion just about not only genetic testing but meeting with specialists and decision making around pregnancy. It's just so stressful obviously you're talking to a couple we're biased over here we are selfish when we want information to help take care of folks. And genetics getting an abnormal genetic test result, whatever the diagnosis, it's really rare.

And so I think a lot of times choosing to do genetic testing, I think there's value, like Dr. Stephenson noted, there's value in having a diagnostic test result because we can do all the things, you know, we can present all of the options. You can meet with all the providers and create a care plan, have control over a situation that doesn't feel like you're in control. You can make those decisions as much as you can and create a plan and prepare your family, learn as much as possible.

But also I think there's value in negative normal genetic test results too, which usually is the case because genetics is rare. It's a big leap to choose to do genetic testing because you're taking that huge question mark but often we are giving reassurance, not always, but often. And there's so much value for all of us in having that normal result in hand for the team, for the family. And you can go into the delivery knowing as much as we do. So I see both sides of the coin for sure. It's a big leap of faith, but we think it's helpful.

Courtney Stephenson, DO:

So we're talking about non-invasive genetic testing and then diagnostic genetic testing.

Erica Newlin, MD:

Right. I was going to say that you alluded to diagnostic testing and we've also said that the NIPT is a screening test. So let's go down the road and say that somebody does have a positive NIPT screening test. What diagnostic testing is available and what's the difference between screening and diagnostic?

Courtney Stephenson, DO:

Right. So the screening test tells you the probability or the chance or the risk to that patient of that condition. If their screening test is positive, then we usually do a very detailed ultrasound and try to see if we see any of the features of what the test is indicating. And then we can offer diagnostic tests which are black and white. We could do a C-V-S, which is a Chorionic Villus Sampling, which is a first trimester invasive test. Or you could do an amniocentesis, which is generally done after 15 to 16 weeks and can be done at any time during pregnancy.

And those are diagnostic tests because they're closer to the fetal compartment. So we're actually looking at the fetus more directly than through the mom's bloodstream. And there are caveats to some of that. But for the purposes of today's production, the CVS and amniocentesis would be definitive and they would give you that black and white.

And those genetics are that baby's genetics the rest of his life, it's, they don't change, they carry them with them. And so it's nice for the family to have the relief, be able to enjoy the pregnancy, have a baby shower without the conflict in their heads about, you know, what may be that they don't know yet. So the genetic tests can be very helpful when they're negative, equally helpful when they're negative for the patient's relief and peace of mind. But they do have risks to them because they're invasive.

And I think that's the discussion that we share is that, do you want to take the risks of, you know, a potential miscarriage which are much lower than they were once thought to be. We have better equipment, we have high intensity ultrasound machines and echo bright needles and our skill sets are better. I think that some of them have gotten a bad wrap in the past. But if the patient needs the information, then that's the diagnostic test that's available.

The amniocentesis is taking fluid from around the fetal compartment, it's just a thin needle and we drop just a few ccs of fluid. And then the chorionic villus sample is more of a biopsy in the placenta. We don't go in the fetal compartment or the space that the fetus is in, we stay behind it in the placenta. So they are the definitive, the black and white result, the bottom line.

Erica Newlin, MD:

How do you decide between the two tests?

Courtney Stephenson, DO:

It's usually gestational age dependent. The CVS can have some false positives. So depending on what we're looking for and some patients may choose to wait for the amniocentesis, the results do take about two weeks to come back. So if time is of the essence and you have this result and you're 10, 12 weeks pregnant, you might want to just do the CVS and get your information so that you can understand what's happening to your pregnancy and have the ability to make decisions without having gotten all the way through the lot of the second trimester.

Marissa Coleridge, MS, CGC:

It's very specific to what we're looking for too. So I would say it's, it's very specific to the patient's kind of story and clinical history too.

Usually, like Dr. Stephenson noted, it's these are representative, these cell types for the placenta and the amniotic fluid, which has kind of the amniotic fluid has the baby skin cells that are floating in there. So that's the DNA that we're looking at. And usually these are equivalent every once in a while we're have to be really intentional about do we want to look at the placental cells? Are they representative of the fetus? And usually they are. But every now and again based on the clinical situation, we have to kind of think that through. So it's not equal all the time. But usually we can kind of think about just based on gestational age.

Courtney Stephenson, DO:

And the, you know, the CVS being able to have results by 14 weeks in the first trimester or earlier second trimester is, I think the biggest difference between that and an amniocentesis is the timing of the information. I think a lot of families in the first trimester are still like a little bit cautiously optimistic and things are early and don't know if the pregnancy's going to stick or that. And then if, if they had a result that were screened positive and they wanted to do a diagnostic test, they can put all that behind them by the time they're 15 weeks.

Erica Newlin, MD:

And how do the risk of pregnancy loss compare between the two procedures?

Courtney Stephenson, DO:

So the risk of pregnancy loss is historically higher with CVS, but more recent literature suggests they're about the same because the first trimester has natural losses that would occur anyway. We don't know if they're attributed to the CVS procedure or not. So we usually quote somewhere around one in 700 for a loss for either procedure. If there's something that we see on ultrasound, say we look at the fetus, we find a thickened measurement behind the neck, the risk for that pregnancy is already higher for loss just with that ultrasound finding. So adding a procedure to it, we don't know the ultimate risk of loss. There are some publications that say the risk of loss is actually lower because the pregnancies that are continuing are normal.

And so those are more intentional. And so CVS it's a little bit tricky, but I personally as a physician feel that it's more about the timing. If you need to know early, then you do the CVS understanding some of the limitations of course. And that's why we work so closely together because we counsel the patients about those things and help them make an informed decision.

Erica Newlin, MD:

Perfect. And shifting gears a little bit to ultrasound. So we historically, historically being like six, seven years ago, would do very frequently what's called the nuchal translucency ultrasound. Can you talk about that test? Is it still valuable? What has replaced that test if anything?

Courtney Stephenson, DO:

So currently the recommendation is the cell-free DNA screen with a first trimester anatomy scan. We do look at that measurement still, but we don't submit it with a risk assigned to it if they've done the cell-free DNA screen. Now, if a patient came in and hadn't done the blood work, then we would assess that area, that nuchal translucency of the space behind the neck and measure it and make an assessment based on that ultrasound picture. It is part of the anatomy of the first trimester. So we still look at, we always look at it.

If it is thick, it can indicate a broad range of things from genetic conditions and syndromes to structural anomalies, lymphatic differences, you know, cardiac anomalies, it's not specific to any one thing if it's thick. And sometimes it's normal.

And so again, that's where the cell-free DNA screen could come in and be really reassuring or invasive testing if the patient wants to know all the genetic information. So we should probably say like cell-free DNA screening technically is the three trisomy and the X chromosome. We have 46 chromosomes. The cell-free DNA screen is testing the most common genetic differences that we see. But we still have a number of other chromosomes that could be different that may not be picked up on the cell-free screen.

So it's important to know that the blood test limitations, while it's very reassuring if we see something on ultrasound, we would talk about what to do next. Do we need to get an echo of the baby's heart? Should we be thinking about doing a CVS and getting diagnostic genetic information?

About 5% of cell-free DNA screens are normal and there's still an anomaly that can be picked up later. So just because the cell-free DNA screen is normal doesn't mean you're totally out of the woods. So we don't want patients to get their cell-free DNA screen result and then not come in for the ultrasound because they go hand in hand. So the first trimester anatomy scan has replaced the nuchal measurement with the cell-free DNA. That combination is now our platform for screening in the first trimester. So it's an ultrasound between 11 and 13 weeks, six days with the blood tests together. That's our screening tool for everyone according to ACOG.

Erica Newlin, MD:

You mentioned that that is the first trimester anatomy scan. What kind of anatomy testing are we doing in the second trimester?

Courtney Stephenson, DO:

So here for high-risk patients, whether they're taking a medication that could make them high risk for structural differences, whether they had a positive screen and they opted out of the cell-free and they just want to look again later and see if there's anything that we can detect. Anyone who's high risk. And there's a list of categories that that would pertain to, would have an ultrasound around 16 weeks and then a detailed ultrasound at 20 weeks.

There are structures, and particularly in the brain that we can't see major things we can see, but like subtle things we still need to do that 20 week scan to look at some of the more subtle differences.

So the major things that are life-limiting can be detected up to 90% of them in the first trimester. So that's where the real value of that first trimester ultrasound comes in. And then the fine details which aren't as catastrophic, we can detect in the second trimester. So like that 16 and 20 week scan.

If you're not high risk, if you're young and healthy and don't take any medications etcetera then you might just come in for the first trimester ultrasound cell-free DNA screen and then come back at 18 to 20 weeks for the detailed anatomy. It's the high-risk patients that do the 16 and then the 20 again.

Erica Newlin, MD:

Great. And then I know there are different levels of anatomy scans. Here at the Cleveland Clinic, we have the luxury of a very high-level anatomy scan. But can you tell us about those different levels and when a higher level might be indicated or when someone might want to seek that specifically?

Courtney Stephenson, DO:

Right. So the first anatomy scans standard, everybody gets the same standard images. Then in the second trimester there's a detailed or standard anatomy scan. The detailed anatomy scan is for the high-risk patients. Again, drug exposures, medications, differences and body habits or risk factors. And then the standard test, the standard ultrasound. We still look at everything because we have the skillset, we have the equipment. We will look at the aorta arch even though it's not on the list, things like that. And we do screen everybody the same.

A low-risk patient could still have a very subtle anomaly that you don't want to miss. And then in the third trimester is a big problem.

Erica Newlin, MD:

And I have a 6-year-old and a 1-year-old and having the five years in between, it's incredible to me the resolution of the ultrasounds and how many more things we can see even in a five-year span.

Courtney Stephenson, DO:

Yes, and I think I, that's why I kind of started with a little bit of, I think all these invasive tests need to be restudied because the ability to see the tip of the needle and know exactly where you're going and avoid the tiny little edge of the placenta or some other areas is really, really remarkable. So since I do fetal invasive procedures, this equipment's imperative and really allows us to do incredible things safely. That's the point is when you can see, and even, if the acoustics 20 years ago would not be good and a patient with an increased BMI now we can see just as well, it's really quite amazing what they've done with the technology.

So yes, it has advanced quite a bit and it does help us to do the nitty gritty. Like we literally count every finger and lenses in the eyes and we can look at ears and things that weren't looked at before. So it's really remarkable what we can see.

Marissa Coleridge, MS, CGC:

It is interesting because people that I talk to, we lean so much on our family and friends and of course, and then they'll tell me like about testing results and their ultrasounds and they'll say like, well I talked to my mom and this happened to her, or I talked to my aunt and this happened to her. And we all honor that because that's what, that's what our lived experience is. But things have changed so much and it for good, but also it's a lot of information in our faces and it's so it can be overwhelming.

And so to your point, like things have gotten better, but it's all so much different than our family and especially the past generation have experienced. So that's a really hard thing especially as each pregnancy is different from the last, I think it's a big change to experience.

Courtney Stephenson, DO:

Yeah, I agree. I think when a patient gets a positive cell-free DNA screen for down syndrome now, that's not the same quad screen from the early two thousands, there's a huge false positive rate in those blood tests. And so I think that's very true that the parents of the patient had maybe an experience where they got a false positive and the test that we have, the cell-free DNA test is much more reliable and accurate than that quad or triple screen that was once done.

So it's an entirely different test. The quad screen, triple screen look at markers in the bloodstream for proteins and the hormones and the cell-free DNA screen is actually looking at the fetal DNA in mom’s circulation. So way closer to the baby and more accurate. Yes, I agree that things have changed and people have had past negative experiences with screening tests and maybe want to avoid them because of all that history or the influence of family members or the experiences maybe themselves, but the testing's gotten much better and more reliable.

Erica Newlin, MD:

And on that note, what do you anticipate changing about prenatal testing in the next five or 10 years in the future?

Marissa Coleridge, MS, CGC:

I want to hear what you have to say Dr. Stephenson about the imaging, but from the genetic standpoint, things are moving fast, which is surprising for genetics. But I think from blood workwise, I think cell-free DNA screening is expanding so that there'll be more screening available that's just more like, so single gene.

So we think about the analogy of, and this is maybe not the best analogy, I apologize everyone, of like a bookshelf. So when we think about chromosomes, that would be just books, your old school set of encyclopedia is up on the bookshelf or pick your favorite novel set and then your trisomies like down syndrome or trisomy 18, that would be just your book. You take it off the bookshelf and you're able just to say like, are there any extra books? Are there any missing books? And that's what we have the capability of right now with the cell-free or the NIPT test.

What's happening now and kind of at the brink of being available or starting to be available is, it's called single gene testing. So looking for like patients that are both sickle cell carriers or cystic fibrosis carriers. And so we're starting to be able to do single gene testing through mom's blood. So basically taking that book off the bookshelf, opening it to a particular page, looking at page two, paragraph seven and saying, is that word missing? Is that sentence present and accounted for? Or is there a mutation or misspelling? Which is really neat.

It's still screening so saying are we at high risk or low risk? So it's not to the point of saying diagnostic testing, absolute yes or no, but it gives us a better idea without having to go through an invasive test. We're starting to get to that place in prenatal genetics medicine and I think that is just going to grow and grow, which is really exciting.

Actually, I was talking to folks in the office that I'm envious of the next generation of practitioners because I think this'll be a really a neat place to be that eventually a lot more will be available just through blood work. So that's kind of where things are going from prenatal genetics that I'm aware of right now.

Courtney Stephenson, DO:

From an imaging standpoint, we just get better and better and more clarity with each generation of ultrasound machine. I personally feel like the ultrasound imaging of the fetal brain is just as good as MRI for a lot of conditions. And so we're not relying on very expensive secondary tests anymore.

And I also hope that in the future we'll develop more tests that reflect fetal physiology so we can have additional tests that tell us that the babies are or baby are stressed or at risk. I think that those things will be coming too with blood flow studies or behavior studies. I think there's a lot that still can be detected that we don't know yet. They seem to get better and better all the time. The 3D imaging is really fascinating.

Erica Newlin, MD:

Yeah. That's all very exciting. Any last notes or anything you'd like to add? Dr. Stephenson?

Courtney Stephenson, DO:

I think probably the take home messages I would add would be if you do cell-free DNA screening and you get a low-risk result, you still need the ultrasound. The first trimester anatomy scan is very valuable and that it doesn't replace the second trimester scan. So whether you're high risk, you need the 16 and 20 or you're low risk, you need the 18-week scan. They're really important and we can see a lot more detail than we used to. So I know there's some families are like, well we didn't do this with our prior child. And that's just because we can see so much more and so much earlier.

Erica Newlin, MD:

What about you, Marissa? Anything to add?

Marissa Coleridge, MS, CGC:

Yeah, I would totally agree with what you just said, Dr. Stephenson. As a fellow anxious girl, I would support that statement and I would just say genetic testing, either prior to pregnancy, during pregnancy, after delivery, if something was identified and you want to come in and talk about recurrence risk, it's never required. It's absolutely a discussion.

And I think our job is always just to talk through and let you know what we know and figure out what's going to be a best fit for you, for your family. Figure out like what's going to best meet your needs. And things are always changing and growing.

And so as we discussed earlier, this pregnancy may be different than the last pregnancy, which is an odd feeling. I think sometimes for folks. My big takeaway message is, you let us know how we can help you and we'll do that.

Courtney Stephenson, DO:

Yes. Everything we do is patient-centered. So our role is to help patients make the best decisions they can for themselves. We're not here to tell anybody what to do, we're just trying to help them navigate all of the complexity, genetic information, and then apply it to the context of the ultrasound imaging. Put the whole picture together and we love our jobs.

Erica Newlin, MD:

Well, thank you both so much for joining me.

Courtney Stephenson, DO:

Thank you.

Erica Newlin, MD:

Thank you for listening to this episode of OB/GYN Time. We hope you enjoyed the podcast. To make sure you never miss an episode, subscribe wherever you get your podcast. Or visit clevelandclinic.org/obgyntime.