Dr. Andrei Rebarber joins Dr. Fox to discuss prenatal care for twin pregnancies. In this episode, they cover specialist care for twin pregnancies, vanishing twins, genetic screening, and more.
“Prenatal Care of Twin Part 1: Early Care and General Advice for Twins” – with Dr. Andrei Rebarber
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Dr. Fox: Welcome to today’s episode of “Healthful Woman,” a podcast designed to explore topics in women’s health at all stages of life. I am your host, Dr. Nathan Fox, an OBGYN and maternal-fetal medicine specialist practicing in New York City. At “Healthful Woman,” I speak with leaders in the field to help you learn more about women’s health, pregnancy, and wellness.
All right, Andrei, welcome back to the podcast. How you doing?
Dr. Rebarber: Doing great. Thank you.
Dr. Fox: Fantastic. So, I’m in New York City. You’re in Brooklyn but we’re still podcasting. The podcast always moves forward. It’s good to have you.
Dr. Rebarber: Correct. The Williamsburg Bridge will not separate us.
Dr. Fox: So, we’re gonna be talking about twin pregnancies today and about prenatal care of twin pregnancies. And obviously, this is something that is near and dear to both of our hearts, not just professionally but personally. You are a twin yourself, yes?
Dr. Rebarber: I am. I don’t remember my in-utero experience but yes, I am a twin.
Dr. Fox: You’re a twin, I have twins, we take care of twins. It’s all twins, baby. It’s awesome. We had a podcast already talking about the, sort of, diagnosis of twins and differentiating, you know, the kind of placentation, you know, identical, monochorionic, dichorionic, and we’re also gonna have separate podcasts on monochorionic twins or twins that share a placenta. So, we’re gonna focus today on the most common, sort of, subtype of twins, which is not identical, two twins that have different placentas as well, and the prenatal care. And the first thing I wanted to ask, which is more sort of a philosophical question, do all women with twins need to see a high-risk doctor during pregnancy, like a maternal-fetal medicine specialist? Now we’re biased because we both are those people, but I’m curious what your take is when people ask you that.
Dr. Rebarber: My general take is that they should at least have a consultation with a maternal-fetal medicine specialist because often, it gives people an opportunity for one full hour to review why we do more surveillance and monitoring in these kind of pregnancies, what the risks are, and managing expectations appropriately, how these pregnancies are different can be affected by either basic things such as diet, nutrition, exercise as well as more complex things like preterm labor, cervical length, preeclampsia. And I don’t think that often enough a lot of patients have a clear understanding of what happens in these pregnancies often and they’re often surprised when certain adverse outcomes occur. And I think managing expectations is important.
Dr. Fox: Yeah. I mean, I agree. I think that for most OBGYNs in practice, when someone comes to them for first visit, second visit, there’s so much to go over. I mean, it’s daunting how much there is to go over just about pregnancy. Pregnancy, what to do, what not to do, what to eat, what not to, what kinda tests we’re gonna do, what kind of visits, how does our office work, what do you do if there’s a problem, who do you call, you know? Doing an exam, is your Pap smear up to date? There’s just so much stuff that has to be done that if someone comes and also has twin pregnancies, it’s gonna be so difficult to cover all of that in a prenatal care visit with your general OBGYN. So, I guess there are OBGYNs who might schedule a separate appointment and who have a lot of experience with twins and might do this themselves but, like you said, usually having a separate consultation with someone just to focus on twins. Like, why do we care? What’s gonna happen? You know, what might happen? What do we do to prevent that? What do we do to manage it is helpful just from an informational perspective because it’s just so unusual to get that on your first visits with your OBGYN, and it’s not their fault, there’s just so much to cover.
Dr. Rebarber: Also, I think that most people don’t even know they’re carrying twins and then they end up in their first OBGYN visit and they get an ultrasound and, all of a sudden, surprise. So particularly for dichorionic, diamniotic twins, that’s not uncommon that that happens. I mean, obviously, if they’re coming through a fertility specialist, they have already been surprised but I think that for the average patient who gets diagnosed with twins, they’re usually a surprise for the doctor as much as for the patient. And often, they’re not scheduled appropriately in the sense of the whole conversation for twins because they don’t know.
Dr. Fox: Yeah. That’s a good point. And I think that over the course of pregnancy, you know…So we practice in New York City and there’s a lot of people who take care of twins and a lot of people with twins seek us out because we take care of twins but also because we deliver twins and I think that’s…again, that was another podcast we did and it’s a separate…you know, you don’t have to be a maternal-fetal medicine specialist to be good at delivering twins. You just have to be experienced, right. Anyone who has a lot of experience delivering twins is gonna be good at delivering twins and it’s not really the high-risk training. But what we’re gonna be focusing on today is sort of the prenatal care of twins. I think that for a lot of people, it is gonna involve a maternal-fetal medicine specialist either as their primary obstetrician if that’s available, right, in some parts of the country, MFMs don’t do deliveries, or at least as a consultant meaning you’ll have your own OBGYN who will take care of you for pregnancy and delivery but you’ll be seeing a maternal-fetal medicine specialist for all of these additional tests, mostly ultrasounds, not entirely, before that. So, there’s different relationships that people might have with an MFM if they’re carrying twins.
Dr. Rebarber: Yeah. I mean, the majority is gonna be a consultative experience with ultrasound and, you know, the conversation about the risks and pitfalls of becoming pregnant or maintaining pregnancy with twins. And again, people go to midwives and OBGYNs for twin management and care and delivery. So, it is rare throughout the country that MFMs are actually involved in prenatal care and delivery of twins. It is more common in urban areas and particularly in more academic centers where you have high-risk, sort of, setups or high-risk clinics where people are dedicated to management of a more complex pregnancy. But in general, that’s not so common in the majority of the U.S.
Dr. Fox: You know, what I tell women when they ask me, “Do I need to see a high-risk doctor?” I say, “Well, there’s two things you need to consider.” The first is just for surveillance of your twins, you probably need a maternal fetal medicine specialist involved, right, whether that’s as your primary doctor or as a consultant in terms of, like you said, the ultrasounds, interpreting them, management, when’s the next ultrasound gonna be, you know, start a medicine, don’t start a medicine, get admitted, don’t get admitted, get delivered, don’t get delivered. Like, those types of decisions. And so, again, that can absolutely be on a consultative basis, and that’s, sort of, part one.
And part two, which is not related to whether the doctor’s a high-risk person or not, am I seeing someone who takes care of a lot of twins? And I think that that’s a really important part of it because, just in general, for people who take care of twins, they know what to expect, they know what’s gonna happen, they, you know, have a sense of what to do, how to deliver them, whereas people who don’t take care of twins, it becomes complicated because they just don’t have experience in that and some people just don’t. That’s just how it works out. And so, I think that’s an important question to ask your doctor or your midwife, “Do you take care of a lot of twins, and do you deliver twins?” And those are questions to sort out at the front end if you might choose to seek care elsewhere with a provider or a group of providers who takes care of a lot of twins.
Dr. Rebarber: Yeah, I mean, a lot is a loaded word anyway because I don’t know what that means. Is it 5 cases a year or 10 cases a year? On average, most OBGYNs will not do more than 10 twin deliveries a year per OBGYN. A group might take care of more but they’re not gonna do more. And so, unless it’s centralized, most places are not seeing a lot. Is it within the purview of routine obstetrical care? Sure. And again, for most obstetrical management and care, if you’re working…if a general OBGYN is working with an MFM, that’s fine but the actual delivery itself can get complicated. And that’s been shown, you know, particularly in a lot of the French studies that if you have centralized care for delivery of twins, you will decrease the chance of C-sections, in particular, C-sections for the second twin and that has to do with the expertise of the delivering physician. But in areas like in France, they have centralized places where twin clinics and twin care is done and delivery’s centralized in areas where hospitals have expertise and the management of that.
Dr. Fox: Let’s pivot and talk about the actual care of twins. So, someone’s pregnant with twins and they’ve had an ultrasound and were confident that they are dichorionic, meaning there’s two placentas, and we’re managing the pregnancy and they’re still in the first trimester, right. So, they’re somewhere, let’s say, between 8 and 12 weeks. And at that time, I think one of the complications that surprises a lot of people is this concept of a vanishing twin, which sounds, you know, sort of very magical in a sense, but it’s not great. But what is a vanishing twin?
Dr. Rebarber: Well, vanishing twin, which happens about 20% of the time, or 1 out of 5, is when you diagnose a pregnancy that has twin gestation where there are 2 sacks, 2 placentas, and across the first trimester primarily, under 10 weeks often…you might diagnose it at 6 to 8 weeks that there were 2 heartbeats and then 1 stops. And so, you are left with a singleton. And that’s not uncommon as most people think and is really a product of our science and technology now because we’re identifying earlier pregnancies than ever before. And so, because of that, miscarriage rates are perceived to be higher but a lot of this has to do with just natural attrition of embryos that are mostly abnormal. And so, at the end of the day, you’re talking about a phenomenon that years ago, we only got scanned, let’s say, at 12, 14, or even 16 weeks or first visit. People didn’t come for prenatal care until after 10, 12 weeks. And so, no one even knew. And nowadays, this concept of the vanishing twin, while probably not new but new from a diagnostic perspective, occurs.
And obviously, that’s a little frustrating or devastating because, again, you’ve had this conversation with patients about twins and managing twins, and people are often excited about having twins, and then all of a sudden you have to tell them, “You’re no longer having twins.” And interestingly enough, the likelihood of miscarriage of the whole pregnancy, while slightly higher, is very low. So, the majority of these pregnancies even after a vanishing twin phenomenon, the remaining fetus has a very low probability of miscarriage and has a low probability or really no greater probability of complications in the rest of the pregnancy if the vanishing twin occurred under 10, 12 weeks. So early vanishing twins don’t really impact on the rest of the pregnancy.
Dr. Fox: Yeah. Sometimes we diagnose people with twins and at the time of diagnosis, we say, “It was a twin pregnancy but one doesn’t have a heartbeat.” So, it’s sort of like…there are people coming who have, like you said, two, you know, viable embryos and then two, three, four weeks later, it’s only one and others where we find it at the time when one…or one may have an empty sack for example and it’s sort of these mixed emotions. Like, on the one hand, you said they were excited to have twins but maybe they were also scared to have twins, and now do they feel relieved or do they feel, you know, concerned? And there’s a lot of, you know…different people sort of process that diagnosis differently. But one of the important things to know is that it’s common, like you said, it’s not a rare event to have this happen. And sort of based on when you pick your initial point but I think, you know, 20% is a good rough number meaning it happens and we have this conversation relatively frequently. And as you said, fortunately for the remaining twin, there does not appear to be any real risk of any direct impact or indirect impact and it typically goes down to a healthy singleton pregnancy, which is good.
What about screening for aneuploidy or genetic abnormalities or Down syndrome in twin pregnancies? Is that different from singleton pregnancies? I know we did a lot of this on singleton pregnancies but are there any parts of twin pregnancies that make it unique? Again, we’re talking about not identical twins, two different placentas.
Dr. Rebarber: Yeah, we can…I was gonna go over that but I would just…just kinda sort of broad stroke about routine prenatal care. I mean, I think that there are many aspects of prenatal care in twins that are pretty much similar to singletons but what’s really important to note is that twins are associated with higher rates of almost every potential complication for a singleton except going overdue and being large, what we call macrosomia. So all [inaudible 00:13:01] of pregnancy are increased in twins and I think twins should know that, that there is a higher risk for multiple complications in there across pregnancy and we monitor these.
One of them is gonna be aneuploidy or genetic screening. So, when you’re talking about dizygotic twins, which…having two eggs fertilized by two sperm means dizygotic and most, most dichorionic, diamniotic twins are dizygotic though that’s not 100%. That means that there are some dichorionic, diamniotic twins which means two placentas, two sacks that could be identical but the majority are nonidentical. When you talk about non-identical twins, they have twice the risk for maternal age [inaudible 00:13:48] you know, singleton pregnancies for having at least one affected fetus as far as chromosomal problems so…
Dr. Fox: It’s two kids so twice the risk. Okay.
Dr. Rebarber: So, when you’re talking about that, there is a little bit of a higher risk of one of the two having a problem. And statistically, the maternal age or break point where we traditionally recommended invasive testing was always around 32, 33 for twins rather than 35. That was when the risk of the procedure exceeded the risk of the event itself and that was sort of the traditional concept.
We don’t usually use age as a, you know, criteria for invasive testing these days or non-invasive screening and there are many options for people nowadays. The most common options for screening involve the basic nuchal translucency measurement where we measure the neck thickness of the baby as a marker of risk for genetic chromosomal problems. And at that same time, a lot of us will do kind of a structural evaluation where we look at the embryos and make sure they’re developing normally and there’s no major structural problem such as abdominal wall defect, spine defect, things like that. Normally, that’s done around 11-and-a-half to about 13 weeks. The later you do it, the better you can see other structural problems besides just the nuchal itself. And so that’s the standard.
Additionally, people have done biochemical screening where they actually look at hormone levels of the placenta as a reflection of risk for Down syndrome, and when you combine the biochemical screening with the nuchal, which is kind of what’s done in singletons, it seems to perform well, but alone, it really doesn’t perform as well as it would be in a singleton. And that has to do with the fact that the hormone levels…the way the lab works it out is it just actually halves the actual hormone levels so you have two placentas and assumes that an equal distribution of these hormone levels are coming from the placentas which makes it a little, you know, unfair because you can…you may have one placenta producing more, one less, and the one that’s producing less particularly for certain of these hormones may affect risk for Down syndrome.
And then finally, something called the nasal bone. A lot of places are also looking at the presence or absence of the nasal bone as another marker for Down syndrome. The nasal bone and the nuchal are actually fetus-specific markers, which means that they actually are telling you about each individual fetus, whereas the hormone levels are actually pregnancy-specific. And so, they are not ideal in twins. And screening this way for chromosomal problems like Down syndrome, something called trisomy 18, 13 is not as good in singleton by about 5% and it’s…5% to 8% as far as sensitivity or pickup.
And then more recently, people are doing non-invasive prenatal screening where you…or what we call NIPT using cell-free DNA where they actually look at fragments of DNA from the maternal circulation, fragments of placental DNA actually, and looking at that as a reflection of risk for Down syndrome and trisomy 18, 13 as well as the gender. They can actually tell you the fetal gender. And that can be done as early as 10, 11 weeks gestation and it’s really quite accurate. So NIPT, cell-free DNA can actually perform better than the traditional nuchal screening even if you combine biochemical and nasal bone. Close to 99% in its pickup rate for Down syndrome. It may have higher what we call test failure rates depending on which company you use but…and part of that reason is that they have actually lower amounts of fetal fraction sometimes. So, there’s a lower amount of placental DNA circulating and so the test may fail as much as 3% of the time, 3.5% whereas in situations where you talk about singletons, the NIPT testing has a lower failure rate, under 2%.
So that’s kind of the difference. The additional piece of information that NIPT can give you is it also can give you information about the fetal genders. And so, you can have gender chromosomal abnormalities, something called Turner syndrome where there’s only one X chromosome, or Klinefelter’s syndrome, which is XXY. So, you can have an additional, extra sex chromosome that creates certain genetic syndromes. So that can give you more information.
And finally, depending on which NIPT company you use, one of the companies that uses a method that’s a little different than the others called SNP-based. So, they look at sequences of DNA within that fragment, simplistically. They actually can also tell you whether they’re dizygous or not, or monozygotic, which means that they’re identical, fraternal. Not all NIPT companies can tell you that. Only one of the companies out there uses SNP-based and they can give you that differential, which can be actually helpful because…particularly for genetic risks as well as some other risks in a pregnancy, it might be helpful to know whether they were identical versus fraternal. So that’s a little bit about screening.
Dr. Fox: Right. And all of these tests are the same tests…other than, of course, the identical or not identical, it’s the same information you would get when testing one baby. But like you said, one of the unique things is when you’re testing twins, other than the ultrasound portion which looks at each individual baby, if you’ve got an abnormal result, let’s say, you wouldn’t know which baby it is, right. So, it could say, for example, there seems to be a higher risk of Down syndrome on one of those screens but you would have no way of knowing which baby we’re talking about. So, if on ultrasound it’s pretty obvious, right, that one looks abnormal, one looks normal, fine. But otherwise, almost always if there’s an abnormal and even, you know, pretty much in any situation, if you’re gonna be testing, like, with a CVS or an amniocentesis, you’re gonna test both just to be sure what’s going on. And so, it really does function truly as a screening test. Like, even if it looks like, you know, it’s very clear that one of them’s abnormal, you wouldn’t know until you actually do the CVS or the amnio to figure out which one it is.
And then, you know, we talked about this little in our CVS/amnio podcast, it’s really important that the person who does that has a good sense of, you know, mapping out which baby’s where, which placenta’s where because if you get back to results that says, all right, one is normal, one is abnormal, you have to remember which one…you know, when you test it, how are you gonna find that one later? You have to figure it out. And so that’s really important.
Dr. Rebarber: If there are no features like an increased nuchal or a structural problem, you can get into…and they can be confusing, left/right on ultrasound versus the patient’s left/right as well as up/down. And the CVS itself can…unless you know what you’re doing because you can have what’s called cross-sampling error. So, the tip of your needle…you may think you’re in one placenta but if the placentas are fused, you may be sampling the other placenta, not the one that you think you were going for. So, expertise in CVS for twins is really quite important, as is amnio but at least those are separate sacks. It has been reported that people sample the same sack, people, if they…because they can’t map out even an amniocentesis. So, CVS and amniocentesis definitely needs a higher level of expertise from the operator and more comfort with that, particularly if the implications of that would be that people may want to stop the pregnancy with the affected fetus, something called a fetal reduction, because if that’s the case, ideally mapping is critical to knowing which fetus was affected or not. But if not, still, you would wanna know which fetus was affected and how you would track and follow it anyway.
Dr. Fox: Now, assuming all goes well and someone gets through the first trimester, you know, no miscarriage, both babies look good, genetic screen is normal or genetic testing is normal. And so, we’re highly confident this is proceeding as a twin pregnancy and all looks okay. How do you counsel women in terms of…let’s just start with the basics. Like, how often they may be coming to the office? Like, how frequent are their visits gonna be, let’s say?
Dr. Rebarber: So, I usually have a conversation that you’re gonna see us more. And basically, at least in our practice, we tend to do every 2 weeks from 16 weeks on. So, it’s usually every 4 weeks before that time, then every 2 weeks from 16 weeks onward until about 32 weeks, and then we see them weekly from that point on. And that’s just a good rule of thumb. Most pregnant women with twins will have a lot of symptoms that are concerning for various conditions. So, for example, preterm labor, which we can talk about little later, but that’s associated with a higher risk in twins. Most pregnant women with twins will have back pain, pelvic pressure, and uterine cramps, particularly earlier. The uterus is growing, it’s stretching at a more rapid rate. So, they will have those symptoms and those are symptoms that if you look at the March of Dimes website, they say those are the symptoms to call your doctor about for risk of preterm labor, but they almost universally have that. Most pregnant women will have, particularly in third trimester, leg swelling, and that could be an early sign of preeclampsia. And so, at the end of the day…and they’re already at higher risk for that. So, when you take into account twins, they’re gonna have more symptoms, more questions, more concerns and they’re at higher risk so they should be seen at a higher frequency. Whether that should be what we do or not, I think that is a subject to more discussion. But I feel that that’s important.
I also…usually, at the first visit beyond the discussion about frequency of visits, we talk about nutrition and I think that’s been near and dear to our discussions that, unfortunately, doctors don’t counsel well on nutrition in pregnancy. And it’s really important to understand that, you know, when you look at the amount needed…mostly…particularly for the second and third trimester, you only need about 300 kilocalories per day per fetus. And so, you may get up to about 600 kilocalories per day above that for twins, but you don’t need to eat for 2 or 3. And overeating is not healthy. Having said that, the normal weight gain for a pregnancy, which can be up to about 20 to 30 pounds, when you’re talking about normal body mass index, you’re going between 40 to 50 pounds of normal weight gain for a twin. And if you have obesity, it’s still about 30 to 40 pounds of weight gain in a twin pregnancy.
So, you do need to gain weight in a twin pregnancy and that’s really important. And you will gain weight. And I think that people should be aware of that. You’re gaining weight in a sense of two fetuses, two amniotic fluids, two placentas, increased breast mass, increased blood volume, which is increased in twins, increased water retention. So, there’s a lot of weight gain but it isn’t necessarily fat weight gain but you’re gaining a lot with twins by the time, hopefully, full term arrives. And it’s normal to counsel about nutrition and we, in our practice, are big proponents that all twins deserve to have…all twin pregnancies, a nutrition consult to go over their diet and understand how…the breakdown of fats, carbohydrates and protein in a regular meal from a practical level point of view and how that applies to that individual and their eating habits and their culture and I think those are really important that we just don’t have the time. But a good, proper nutrition consult to allow for the appropriate weight gain in pregnancy, the appropriate caloric intake should be standard of care in twins. And there’s data to suggest that inappropriate care is associated with more complications in pregnancy. And so, it is one of the most basic interventions we can do to optimize outcome and fetal wellbeing in a twin gestation.
Dr. Fox: Yeah, I totally agree. When I see twins at the beginning of pregnancy and we have a consultation, you know, they think I’m gonna be talking about, you know, high-tech fancy tests and treatments and, you know, this sort of cutting-edge research and it’s like…we spend so much time talking about nutrition. And we’ve seen this in our own studies and it’s been shown elsewhere that, you know, for twins, it’s not just, “Oh, expect to gain more weight. Like, don’t be upset if you do.” It’s like, “No, you really need to gain more weight.” And when people gain what’s recommended, which ends up being for most people, on average, about a pound a week once they’re, you know, not throwing up so much in the first trimester, which is a lot for people to gain. If they don’t do that, they have worse outcomes. And when they do it, they tend to have better outcomes. And obviously, it’s not, like, the only factor that comes into play but it’s so important. And I agree., it’s just…We’re probably gonna have a separate podcast on nutrition in twins itself because there’s so much to talk about but it is a really important topic to go over.
And then what do you tell women with twins, again, we’re talking about early pregnancy, about general things like exercise or working or having sex? I mean, what do you talk to them about?
Dr. Rebarber: Often, as far as work and sexual activity, I don’t really give any restrictions on those for uncomplicated pregnancies. Obviously, if they have a short cervix, if there’s vaginal bleeding, placenta previa, we do have restrictions on intercourse but those are about it. As far as exercise, traditionally, and I remember this from my residency, in twins, they were told at 20 weeks to go on bed rest and that was sort of the routine, or don’t exercise. But there’s actually data in singleton gestation which is just the opposite that those who are exercising and physically active in pregnancy, particularly for singletons, they have lower rates of preterm birth, not higher risk. So, the data is…we don’t have a lot of data on exercise and twin gestation and it’s not great data but we do recommend that particularly those patients who were regularly exercising may continue.
There is no known, sort of, heart rate at which they actually…it would be dangerous to exceed, though generally, most people suggest somewhere between 130 to 140 that you might at that point when you exceed heartrates in that level while you’re exercising, you might be pulling blood flow away from the pregnant uterus to muscle and so theoretically…most of this is actually from animal data. Not really great human data, and certainly not good twin data, but it suggests that they would slow it down. But exercise is healthy, it’s great. It actually builds stronger bones, muscles. It allows for better labors and lower C-section rates. So, patients should be exercising regularly anyway and they should be [inaudible 00:29:07] exercise. I don’t restrict it in routine situations and, in fact, encourage them to begin an exercise regimen or program.
Particularly if they’re just starting, I generally recommend getting a trainer or somebody who has some skillsets in management of pregnancies. We generally don’t recommend core training, core work, but cardiovascular work is fine, swimming is fine. Yoga, certain positions, probably not, but yoga’s a great form of exercise in pregnancy. There’s actually data on the safety of yoga in pregnancy. Those are the things that I generally routinely talk about. Obviously, no smoking, no drinking, and we talk about the routine things about avoiding cold cuts and well-cooked meats and things of that sort as well.
Dr. Fox: Yeah, I mean, I totally agree with exercise. I’m a big proponent of it and I also tell women, “You know, when you deliver these twins, you’re gonna have two kids to take care of and you gotta be in good shape.” I mean, it is not easy to do if you just spent the past 20 weeks in bed. You know, you have muscle wasting and just, you know, it’s just really, really tough. And so, unless there’s a complication, I encourage women to exercise. And it could be as simple as a brisk walk every day for 20 to 30 minutes where your heart rate goes up and you’re sweating a little. Doesn’t have to be high-tech. A lot of it’s just cardiovascular.
What I wanna do is we’ll talk about a couple more things related to, sorta, general prenatal care of twins and then we’re gonna sorta shift and talk about, you know, risk of preterm birth and growth restrictions. That’s its own, sorta, topic. But in terms of general care, like you said, twins are at an increased risk of everything. You know, for gestational diabetes, which they’re at an increased risk of, there’s not that much to do about it. I mean, I think good nutrition and exercise might reduce that risk a little bit but a lot of it is just related to how the body responds to the placenta. So, we screen all women with twins like we would singleton pregnancies. And if a woman with twins gets gestational diabetes, you know, the management is very similar. The outcomes tend to be good. In fact, and we could talk about this in a separate podcast, it’s really unclear if twins even have gestational diabetes or not because we’re using singleton criteria and that’s a controversial thing but it’s not something to really worry about with twins.
Dr. Rebarber: I would just say normally we screen them between 24 to 28 weeks unless they have other risk factors. Sometimes we’ll screen them earlier at around 12 weeks or so, 14 weeks if particularly…or earlier if they have preexisting obesity, or you might add PCOS, you know, advanced age. Those are, you know, situations where there might be a higher risk for gestational diabetes and you wanna catch it earlier. The data on twins and twice screening…and there are people who routinely recommend screening twice in a pregnancy for diabetes in twin gestations but I think that’s pretty aggressive and certainly the literature doesn’t support routinely doing that, only in some unique situations based on risk factors. Most of the time we just screen them with the same criteria, 24 to 28 weeks. Whether the disease exists or not in twins and, you know, needs to be treated, that’s a whole other conversation that is more academic than practical. But I think for all our purposes, yeah, we do that.
Dr. Fox: Yeah, and again, gestational diabetes is not something to be worried about. I think preeclampsia is something that is a little more concerning because it is more common in twins and there are a lot of overlapping risk factors, meaning one of the risk factors for preeclampsia is also as women get older and twins are more common as women get older. Using fertility treatments, more commonly twins. So, I mean, there’s a lot of things, or even the twins itself increases the risk but also women who have twins are frequently at an increased risk. It’s one of the things…we screen for it in terms of checking blood pressure but it’s something women know about. One of the things we do in our practice is we have all women with twins take a baby aspirin, which has been shown to lower the risk in all women, but certainly in higher risk women it’s more effective. And so that’s something we do in our practice and I think more and more doctors are recommending that, for women with twins, to take a baby aspirin every day along with their prenatal and other supplements.
Dr. Rebarber: Yeah, I mean, it’s not…we were doing this for the past 20 years with the baby aspirin.
Dr. Fox: Before aspirin was hot. We were…
Dr. Rebarber: Just before it was hot.
Dr. Fox: …early adopters, yeah.
Dr. Rebarber: But the data and now the U.S. Preventative Task Force high-risk criteria, which are endorsed by the American College of OBGYNs, suggests that multifetal gestations, patients with chronic hypertension, patients with a previous history of preeclampsia, type 1 or type 2 diabetes, chronic kidney disease and certain autoimmune disorders like phospholipid antibodies or lupus, those are the high-risk people to develop preeclampsia and in those high-risk cohort and in that…all those medical conditions, multiple gestations are included in that. They all are recommended to go on a baby aspirin and for the prevention of preeclampsia. And it does seem to modestly decrease the risk by somewhere on the order of 5% to 10%, maybe a little more depending on the risk factors. So, it’s not that it’s a cure-all but it does seem to decrease the incidence and I think that’s worthwhile to do.
So, in all of our patients, we recommend that they start at some…and it’s important when you start, ideally, it should be under 16 weeks. We generally recommend somewhere between 10 to 12 weeks to start. There suggests some data that you can even start it earlier but certainly, you wanna start it before 16 weeks. After about 20 weeks, there probably is little to no effect to start, as far as the prevention of preeclampsia, so it’s probably worthwhile to know about this early and start early with the baby aspirin. And we’re not alone because there’s standard guidelines that suggest this may be a beneficial intervention on a routine basis.
Dr. Fox: Fantastic. So, Andrei, I think what we’re gonna do is…this was a really good review of, sort of, the general overview of prenatal care of twins and what to expect and how we counsel women and, sort of, what things we do a little differently. And I think what we’re gonna do is we’re gonna stop part A here and we’re gonna then pick up again with part B, which is a really interesting and fascinating topic in prenatal care of twins, which is the prediction and prevention of preterm birth and also fetal growth restriction. So, everyone, stay tuned for that podcast next week.
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