Dr. Fox and Dr. Simi Gupta discuss placenta previa, a relatively common condition that occurs early in pregnancy. Dr. Gupta urges patients not to Google the condition, because it is typically much less serious now than in the past. They also discuss diagnosis and treatment plans for placenta previa.
“Placenta Previa: Don’t Rely on Google!!” – with Dr. Simi Gupta
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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’m 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.
Dr. Gupta: Thank you, Nathan. I’m happy to be back.
Dr. Fox: How have you been?
Dr. Gupta: I’ve been good.
Dr. Fox: Good. Enjoying the pandemic?
Dr. Gupta: I guess as much as any of us can say that.
Dr. Fox: Well, it’s nice to see you in person, which is always good. We’re not doing this over Zoom, so that’s good. So we’re gonna be talking today about placenta previa, which is something we talk about a lot, actually, during pregnancy.
Dr. Gupta: We see it very, very often early in pregnancy. So, I honestly have this conversation with patients at least once a day.
Dr. Fox: Yeah. And I think that it’s important to sort of get information out there because, you know, this is one of the things where Google can take you to a very bad place very quickly. Someone finds out they have this, and they think it’s like, all right, that’s it, game over. When, in fact, that’s not the case for pretty much almost all women who may have this early on pregnancy.
Dr. Gupta: This is correct. It’s so common early in pregnancy. And if patients do go to Google, then they can be taken down a scary road.
Dr. Fox: So, let’s just start from the basics for our listeners. What exactly is a placenta previa?
Dr. Gupta: So, a placenta previa is where the placenta is close to or covering the uterine cervix.
Dr. Fox: Okay. So if it is covering the cervix it’s called placenta previa, and how is it sort of determined where the placenta ends up? Is it by chance sort of, or is it some women are more likely to have it than others, or what’s the most common reason we end up low down by the cervix?
Dr. Gupta: Right. Usually, it’s by chance, but there are definitely some cases where it’s more likely to be lower down. So, the most common reason would be somebody who’s had a prior surgery on their uterus like the cesarean section, and those patients, it’s more likely to be lower down. Or if you have twins or multiple gestations, then there’s more placentas or a larger placenta. And so, it’s also more likely to be lower down or close to the cervix.
Dr. Fox: It’s almost like a game of darts where the placenta ends up. And most of the time when the embryo implants in the uterus, it’s sort of in the middle portion or higher up and so the placenta does not come anywhere near the cervix. If it implants the lower down at implants, the placenta is certainly at least gonna start over the cervix and then as we’ll talk about, maybe it won’t end up there, but it may start there. So, okay. So that’s what a placenta previa is and why do we care? Like, why is it such a big deal if the placenta’s over the cervix for those who may not know?
Dr. Gupta: For most of the pregnancy, it doesn’t matter. The issue is, is that when a woman goes into labor, her cervix is gonna dilate or start to open because the baby needs to make its way out. And if the placenta is covering that area or close to it, then it can start to bleed when a woman’s in labor or contracting.
Dr. Fox: Right. And so in the past, and by in the past, I mean, let’s say 100 years ago, this was a cause of mortality. Women would die from having a placenta previa because it wasn’t known because we didn’t really have ultrasound to look at it, and they would be going about their way in pregnancy and then they go into labor and they’re hemorrhaging when they’re in labor and they didn’t really… You know, 100 years ago, I guess they did, but, you know, 115 years ago to have a C-section for this, it really wasn’t done enough and it wasn’t safe enough, and so it wasn’t an option.
Dr. Gupta: Right. Exactly. And 100 years ago, you didn’t know you had a placenta previa until you were actually bleeding in labor and then it turned into a true emergency.
Dr. Fox: Right. And so, like, one of the issues that we’re talking about with the Google is, you know, if you open up an obstetrical textbook or any article, they’ll always talk about placenta previa and it’s crazy dangerous. It’s a risk factor for every…the mom dying, the baby dying, horrible, horrible things. And that is all true. And it all used to be the case, but nowadays that’s really not how it happens because nowadays it’s unusual that we wouldn’t know about it before labor and that the doctors know, the patient knows, everybody knows. And so at the first sign of bleeding, we know what to do and we can always do a C-section if we have to. And so, nowadays, it’s very unusual to lead to those events. If we manage it appropriately, obviously you ignored it, you can have that, but who’s gonna ignore it? And so, it’s one of the reasons you have to sort of be careful when reading about it, to make sure that you don’t, like, think it’s suddenly gonna, you know, you have to like, you know, get your affairs in order, so to speak, if you have a placenta previa.
Dr. Gupta: Right. Exactly. So the old literature would be somebody comes in bleeding and then you would diagnose this placenta previa. In modern day, we know about them in advance. And again, most of the time it turns out not to be anything concerning. So it’s rare for somebody’s first knowledge of them having a previa to be bleeding in this day and age
Dr. Fox: It happens, but it’s really the exception now. And so, what is it that we have now that allows us to know about this in advance that wasn’t being done routinely before?
Dr. Gupta: Right. So, of course, the big difference now is ultrasound and the quality of ultrasound that we have now. Obviously, the vast majority of patients in this day and age get an ultrasound somewhere in the middle of their second trimester of pregnancy to look at the baby. And in addition to looking at the baby, it’s routine to look at the placenta and specifically where the placenta is. So this may be picked up as early as 16 weeks of pregnancy or at 20 weeks of pregnancy. At that point on everybody’s routine ultrasound, they will look at the placenta and see where it is and know if it’s a placenta previa or not.
Dr. Fox: Right. And when we do the ultrasound, sort of the standard that everyone gets would be what we call a transabdominal ultrasound, which basically means the ultrasound probe goes on the mother’s abdomen and her belly and we look. And most of the time we can see the placenta and exactly where it is and say with pretty high confidence, it’s not a placenta previa. But if we suspect that it is, or that even it just might be a placenta previa, then the better way to know for sure is we do a transvaginal ultrasound because then we have the tip of the probe of the ultrasound, right at the cervix, and you can see, as clear as day, what is the point that’s the inside of the cervix. We call that the internal cervical OS, O-S, and where’s the edge of the placenta. And you can see, is it overlapping the cervix? Is it near the cervix? Like, how far away is it from the cervix? And we can make that measurement very easily pretty much in anybody.
Dr. Gupta: Correct. We start with a transabdominal ultrasound on everybody. We kind of get an idea of where the placenta is. And if we’re worried about it, then those patients would get a transvaginal ultrasound to see if it’s a placenta previa or not.
Dr. Fox: Right. And if you get the right picture and it’s almost impossible to miss if you’re doing a vaginal ultrasound. Abdominally, it happens sometimes that we think the placenta is not a placenta previa and perhaps like the edge of it is near the cervix. And that could be the instance where someone shows up later in pregnancy bleeding, and then you do the transvaginal and diagnose it. But again, even that is rare. Almost always, it looks low enough that you’re gonna do a vaginal.
Because even though the vaginal ultrasound might be annoying, let’s say, or uncomfortable potentially, but it’s not dangerous to the mother. It’s not dangerous to the baby. If you have a previa, it’s not gonna cause bleeding, it’s just a way to diagnose it and you really get all the information you need. And so, it’s really, really rare to go through pregnancy and get routine ultrasounds and not know that you have this.
So that’s good. So knowing is good. Now, just in terms of some terminology, because there are a lot of modifiers for the term placenta previa, there’s complete previa, partial, marginal, low lying, you know, all these different terms. So, just so people understand, when we refer to a complete placenta previa or just placenta previa, what do we mean by that term?
Dr. Gupta: Right. So a complete placenta previa means the edge of the placenta is covering the internal cervical os, so covering the inside of the cervix.
Dr. Fox: Right. So basically when people say placenta previa, they really should be meaning this, like I have a placenta that is covering the cervix. In our terminology, we say complete only because there are other types that have the term previa. And it’s just to be very clear. And so, when it’s near the cervix, but not covering the cervix, there’s different terms. Some people will call that a partial, some people call that marginal, some people call that low lying. Based on who you ask, when you ask them, those terminologies have changed over time. But they essentially indicate that the placenta is close enough that she may end up bleeding in labor, but not actually overlapping the cervix so the risk is lower than a previa, meaning it’s somewhere between “normal” and a placenta previa.
Dr. Gupta: Exactly. And, you know, again, right, like you said, there’s different terminology for it, but we would worry if the edge of the placenta is within 2 centimeters of the internal os or the cervix, we call that a marginal placenta previa. But like you said, there’s other terms for it. And that’s when we would worry about it.
Dr. Fox: Right. I think one of the important points there is, for example, in our ultrasound unit, the terminology to us is almost irrelevant, right? For us, I’m gonna wanna know, is it a complete previa? And if it’s not, how far away is it from the cervix? Is it 3 millimeters, 1 centimeter. 1.5 centimeters? I’m not gonna care if someone calls it marginal or partial, it doesn’t matter. You wanna know the number. And so, a lot of women, they’ll come to us and they’ll say, “My doctor said my placenta was low.” And I’m like, what do they mean by that? And because, you know, I don’t know what that means that the doctor may have meant a complete previa or he or she may have meant it’s not a previa at all.
So, for women who have this diagnosis, it’s important to clarify with your doctor, what do you mean? Is it a complete previa? Is the placenta covering my cervix? Is it just near the cervix? If so, do you know how far away it is? Have you done that measurement? Because it helps identify how much of a risk she’s at, but also as we’re gonna talk about the likelihood that it might move away from the cervix over the course of pregnancy.
Dr. Gupta: Right. I agree. And especially, if for some reason you’re getting ultrasounds done in different locations, then the number is the most important part about that.
Dr. Fox: Right. And it’s also, as you said, it’s pretty common. I mean, at 20 weeks, probably about 5% of women, 1 in 20 have it. At 16 weeks, that number is even higher. It’s probably, you know, 10% to 20% of women have it. So, again, you’re running an ultrasound, you’re checking, you’re gonna see this all the time, tell people. But by the time women deliver, it’s actually less than 1% of the time, which means that most of the women who have it at 16 to 20 weeks, they’re not gonna have it anymore. So how does that happen? How does the placenta move away from the cervix?
Dr. Gupta: Right. So that’s, you know, the first thing that I like to tell patients when I make this diagnosis at 16 or 20 weeks, is that even if you have a placenta previa at that point, it is likely to move. And by moving, we just mean that the placenta is no longer within 2 centimeters of the cervix. And that usually happens just because the uterus gets bigger over the course of the pregnancy. So the baby grows, the uterus grows and there’s more space between the placenta and the cervix.
There’s also another theory that the placenta kind of starts to migrate towards the top of the uterus and therefore migrates away from the cervix. In either case, the truth is just that there’s more room between the cervix and the edge of the placenta over time. And that’s why the vast majority of patients who have one at 16 or 20 weeks will not have one around the time of their due date or delivery.
Dr. Fox: Totally true. And it’s important for two reasons. The first reason is like what you were saying is for the majority women who have it, it’s going to move out of the way. And so they won’t have it at a time they deliver. And it’s something we follow over the course of pregnancy. We can tell has it moved, how much has it moved? How much does it have to go? All these things. That’s number one. Number two is since the placenta only moves up and away from the cervix, if you don’t have a placenta previa at 16 or 20 weeks, you are not gonna have it at the time of delivery unless someone just got the picture wrong, right?
Dr. Gupta: Exactly.
Dr. Fox: Unless it’s misdiagnosed, which is not really typical. So if we know that the placenta is away from the cervix a certain amount, it’s at least that far away as you move further in pregnancy and generally more far away. So that’s a really important thing it’s it only moves up, it does not move down towards the cervix.
Dr. Gupta: Right. And in that same kind of line, once it’s moved away over the course of the pregnancy, it’ll never move back down. So it’s one direction only, which is good.
Dr. Fox: It’s a one-way street. Okay. So we know what a placenta previa is. We know why we care. We know how common it is and the fact that it’s most likely gonna move away, but still when we see it, we do take it seriously because there is the potential of problems happening between then and delivery, right? So what kind of things could happen to someone who has a placenta previa between when we diagnose it and either it moves away or the time of delivery?
Dr. Gupta: Right. Prior to delivery, the biggest concern is that patients have bleeding. And kind of classically, we say it’s painless bleeding at some point during the pregnancy from the placenta previa. And that’s why we watch it. You know, in small amounts, the bleeding may not be anything concerning, but heavier bleeding can be dangerous to the mom and to the baby and that’s why we watch for it
Dr. Fox: Even, I mean, with labor, their risk of bleeding is very high. Without labor, you know, some women don’t bleed at all and some women bleed all the time. And we don’t really understand why that is, why one woman will have no bleeding with the same looking placenta and cervix in terms of their relationship, and another woman may have bleeding continuously and get admitted to the hospital. There’s something about that interface between the placenta and the cervix that’s a little bit more tenuous than maybe between the placenta and other parts of the uterus. And so, it’s more likely to shift a little and move a little and the placenta, there’s a lot of blood flow through there. And so, there’s a potential for bleeding. Now, the bleeding is the mom’s blood, not the baby’s, it’s maternal bleeding. So that’s important because there’s other conditions where that’s not the case. And so, if a woman has a placenta previa and she’s not bleeding, do we give any special instructions in pregnancy? Or what is our typical management in that circumstance?
Dr. Gupta: If this is just something we diagnose on ultrasound at 20 weeks, and as you said, the patient’s not having any bleeding, then we’ll usually just monitor it with ultrasound and we’ll look periodically every month or less frequently than that to see if the placenta’s moving and what the location is. And then the biggest precaution we give patients is we don’t want them to do something that might trigger bleeding. And classically, this would be vaginal intercourse. So no vaginal intercourse if you have a placenta previa because it may lead to bleeding. And then from a doctor’s perspective, you don’t wanna do any pelvic exams in that case because that may also trigger bleeding.
Dr. Fox: Right. And by pelvic exam, that means to try to put your finger through the cervix.
Dr. Gupta: Correct. Not an ultrasound.
Dr. Fox: Right. Because when we do something like a speculum that goes in the vagina, but not in the cervix or an ultrasound that goes in the vagina and not in the cervix, those have been proven to be safe but they’ll cause bleeding. But, you know, no one’s really done a fantastic study that proves that, you know, having sex is gonna cause bleeding. But I think everyone’s sorta like it’s better to be cautious in this circumstance because the bleeding can be pretty severe. So we tell people don’t have sex. In terms of activity, we do not tell people they need to be on bed rest. We usually tell them with their exercise to, like, modify so they’re not doing anything too active, you know, like jumping up and down, things like that. Everyone has different instructions exactly, but somewhere between lying in bed and exercising, there’s a happy middle ground for what should be done. And then we just follow.
And like you said, most of the time, it just moves away and then we lift all the restrictions and it’s literally as if it never happened. There’s a few things we do look for in women who used to have a placenta previa and it’s now gone. Specifically, there’s a condition that’s for another podcast called the vasa previa where sort of the placenta leaves a blood vessel behind, which is actually a baby’s blood vessel. But other than that, if it’s not there, when the placenta moves, we sort of say, all right, you’re done. We don’t have to think about this anymore. We like cross it off the list of problems and she doesn’t have to worry about it. Now, what about in someone it doesn’t move away? So the placenta is just not moving, they’re in that 1% or whatever it is that is persistent and they’re not bleeding. When do we deliver them in that case?
Dr. Gupta: So, you know, these are the patients that we’re, obviously, the most concerned about. And again, the concern is if you have a placenta previa and you go into labor, there can be bleeding in that case. And so, these are the patients who need the caesarean section to safely deliver the baby and the placenta. And we try to plan these C-sections to the best of our ability before a woman goes into labor. But we also don’t wanna do them too early because we don’t wanna take the risks of prematurity for the baby. And that line is somewhere around 37 weeks or so.
Dr. Fox: No one knows for sure that the earlier you go that less likely she’s gonna show up in labor bleeding, but the higher the risk the baby will be in the NICU and have potential complications the later you go. So, we usually draw the line somewhere in that range, 36, 37 weeks and we do a C-section. Now, if she came in labor beforehand or bleeding, obviously, we might do it earlier sort of on a more emergent basis, but as a scheduled basis, if the placenta is covering the cervix, a placenta previa, usually 36 to 37 weeks. If it’s near the cervix but not covering, there’s a lot of debate. A, if you should do a C-section as opposed to laboring and, B, when you should do that C-section and there isn’t one way to do this. Some people think it’s not a good idea to labor at all if the placenta’s within 2 centimeters of the cervix. Other people will allow it, but with the understanding that she may bleed a lot in labor and then plan will have to change. And a lot of this is also discussion with the patient, what kind of risks she’s willing to tolerate.
And those settings will sometimes wait longer for the caesarean because also, it gives more time for the placenta to move, which it may do at the end. And the baby can mature a little bit and the risk of bleeding is lower. So that’s, again, for someone with a placenta previa, not bleeding, follow, hope it moves out of the way, give some precautions. If it doesn’t move out of the way, we’ll do the C-section usually 36, 37 weeks. If it moves out of the way, it’s done. Okay. Now what about the woman that comes in bleeding with a placenta previa, then what?
Dr. Gupta: For this, it kind of really depends on how far along in the pregnancy she is. But our first steps, if we know a patient has a placenta previa and they’re bleeding, is we do want to evaluate them in the hospital and make sure that they are stable and the baby’s stable. And by saying that, you want to see how much mom’s bleeding, how much blood has she lost? Does the baby look okay on ultrasound and on the monitor, just to make sure everybody’s stable? And if everybody is stable and the bleeding slows down and stops, then we can usually watch mom and baby in the hospital for a couple of days and then let her go home and manage as an outpatient. If mom is bleeding significantly or if there’s some concerns for the baby not kind of tolerating this, then we may have to, like you said earlier, do the C-section earlier. So if there’s some kind of emergency, then we would do the C-section earlier in the pregnancy.
Dr. Fox: Right. I mean, part of the problem is we don’t have any treatment to stop bleeding from a placenta previa. I mean, if it’s happening, we’ll generally tell them, they’ll be lying in bed. They’ll be staying mostly still. Whether that helps or doesn’t help, we don’t know. But there’s no medication I can give. There’s no procedure I can do. There’s nothing other than we literally hope that the bleeding stops or slows down.
And as you said, most of the time, it does, but we hope. And then we also prepare for the possibility that she’s gonna need to be delivered early. So if a woman comes and she’s 30 weeks pregnant, and she has a placenta previa, and she’s bleeding, again, if it’s very light, hopefully it’ll stop, and things will come down. But if it’s continuous, we’re saying to her, like, “Listen, if this progresses, we may have to do this C-section now, and, you know, you’re 30 weeks, the baby’s premature.” So there’s medicines we give potentially to sort of improve the baby’s lung function. We give steroids, sometimes something called magnesium. So if the baby has to be born prematurely, the outcomes tend to be better if we can give these medications. And that’s so we sort of prepare for a possible preterm delivery even if it doesn’t end up happening.
Now, you said it’s interesting, if someone, they come, they’re bleeding, they stop bleeding, then we send them home. That’s also somewhat controversial about exactly who should go home and who should stay in the hospital. And I’m not claiming there’s a right answer, but let’s sort of just talk about the back and forth there. Like, why would we think someone should go home versus stay in the hospital in that circumstance?
Dr. Gupta: Like you said, there’s no kind of magic ball to kind of see if someone bleeds and then stops bleeding, are they gonna bleed again? When are they gonna bleed again? How heavy is their next bleed gonna be? So a lot of this is just kind of, you know, coming up with the optimal plan with the patient. One thing we use is how many times has a patient bled? So after a first bleed, we may be more inclined to manage the patient as an outpatient. After a second bleed, or definitely after a third bleed, we usually say, okay, now we really think you are, or this specific patient is prone to bleeding and they should stay in the hospital. So the number of bleeds is definitely one of the big factors that we use.
Dr. Fox: Yeah. People who bleed tend to bleed. It’s just, you know, if you take two women with placenta previa and one of them in the past month has bled three times and the other one’s blood zero times, they each could show up with a heavy bleed, but the one who’s bled before is more likely… Which makes sense, obviously. And the other thing is you can’t predict how heavy the bleed is gonna be. So someone says, “Oh, I’ve had light bleeding every time. It wasn’t… You know, I got to the hospital in an hour and everything is okay.”
Yeah. If I knew the next bleed is gonna be light, then I would say, “Sure, just come when you start bleeding.” But sometimes, it just is profuse from the very beginning of the bleed. And then, you know, you’re away, you go to another hospital, it’s an ambulance, it’s a whole situation. So that’s one thing if they’re bleeding. But also, sometimes it’s just logistical, where do they live? So, yeah, someone lives in… We deliver in New York City. If someone lives in the city, that’s one thing. But if they live two hours away in Southern Jersey, that’s a different situation.
Dr. Gupta: Right. Because once you start bleeding, you know, obviously, it’s very nerve-wracking for everybody involved. And in many cases, if you go to your closest hospital, they may not be a hospital equipped to handle this type of situation.
Dr. Fox: Or the baby.
Dr. Gupta: Or the baby. Right.
Dr. Fox: If the baby is premature.
Dr. Gupta: Exactly. There is no timeline, but if you live close to the hospital where we feel more comfortable with managing you as an outpatient versus if you live further away.
Dr. Fox: Yeah. It’s always a tough conversation because if you’re sitting with someone, you know, they’ve had a bleed again at 30 weeks pregnant, let’s say, and it slows down after a couple of days. In the one hand, you can say the safest thing is to stay in the hospital. But the vast majority of people don’t need to stay in the hospital. And you’re talking about staying for six weeks in the hospital, which is a big…
Dr. Gupta: Or longer.
Dr. Fox: Yeah. Which is a big burden potentially for her financially, logistically, she has other kids at home, it’s depressing to be stuck in the hospital. It could be expensive. I mean, there’s all these reasons people don’t wanna be in the hospital for a long time. And so that’s the downside, but what if she has a huge bleed in two weeks then, yeah, you wish you were in the hospital when that happened because you can intervene sooner. And so, there isn’t…it’s a conversation and there isn’t really a great way to figure this out other than to just go through it and see what the options are. I always tell women when they’re going home, the truth is, I tell all women with placenta previa that these recommendations that they’re after 20 or 24 weeks. But certainly, those who’ve got admitted and sent home, like, you need to have a jump plan. At every moment in time, you need to know like, what am I gonna do if I start bleeding?
And the reason that’s important is, for example, if you have another child at home, don’t be like in the park 20 minutes from home with your child because what if you start bleeding, right? Like what are you gonna do with your kids? So you need some sort of plan at all times, who’s gonna come, where am I gonna go? Am I calling a cab? Am I calling an ambulance? And it may sound like being too cautious, but it’s not because when these things happen, you don’t want it to be a disaster.
Dr. Gupta: Right. Because that’s not the point to be considering the backup plan.
Dr. Fox: You want the plan to be ready. And for some women, the right thing is to stay in the hospital. And they do. Hopefully, they’re there for a very long, boring time and nothing happens, and we just do their C-section. And for some of them, they do bleed over, and over, and over and we have to make a decision to deliver them at some point. And when women are delivered with a placenta previa, so we do it by cesarean as you said, one of the things we also talk about is anyone with placenta previa has a higher risk of another condition, which again, is gonna be another podcast, called placenta accreta. So just in broad strokes, what is a placenta accreta? It sounds like previa, but it’s different.
Dr. Gupta: Right. So in general, there is like a layer between the placenta and the uterus, which allows the placenta to come out after the baby’s born. And that’s why, usually, it’s very easy to remove the placenta after a baby’s born. With a placenta accreta, the placenta actually grows into the muscle of the uterus and there’s different versions of it. But essentially, it grows into the muscle of the uterus and makes it difficult or nearly impossible to remove the placenta in those cases. And in those cases, you actually have to do a hysterectomy or remove the entire uterus after the baby’s born in order to stop the patient from bleeding.
Dr. Fox: Right. And those are, again, different conditions. The previa is based on the location, where it was the placenta is covering the cervix. Accreta is whether it’s stuck or not stuck. They both put you at risk for bleeding, but there is overlap. Meaning if you have a placenta previa, the risk of an accreta is much, much higher than if you don’t because that layer is not as well-developed lower down in the uterus. So, for example, if someone has a birth and they don’t have a placenta previa, it’s their first baby, the chance that they have an accreta is one in thousands. I mean, it happens, but it’s very, very, very unusual. But if they have a placenta previa, it’s like 1% to 2%, which is a low number, but it’s a lot higher than one in thousands. And that’s on a first baby.
If someone has a history of a cesarean, I mean, this is their second baby and the first was a cesarean and now they have a placenta previa, it actually goes up to like 10%. And then if this is your third cesarean, you’re talking somewhere between 25% and 50%, meaning it starts to get really likely. And so, when we see women with a placenta previa, we’re always thinking that maybe she’ll have a placenta accreta, particularly if she’s had prior C-sections and we prepare her for that possibility as well.
Dr. Gupta: And the correlation between that, between a C-section and a previa is this idea that the area where you cut into the uterus for a prior cesarean section, that area is somehow stickier. And so, for some reason, the placenta is more likely to attach in that area or to grow into the muscle in that area.
Dr. Fox: Right. And so that sort of likelihood also comes into our, you know, thinking about how to manage when to deliver, whether to send her home or not. Meaning if it’s someone with a placenta previa and three prior C-sections who’s coming and bleeding, we’re much, much more worried that she has a placenta accreta and is gonna need an earlier delivery, you know, higher chance of hysterectomy. And so, she’s more likely…we’re more likely to give her stricter precautions, be in the hospital, deliver earlier, those things than if it’s her first baby, for example, when those things are possible, but not quite as likely. So, again, accreta is its own podcast. It’s a fascinating topic. Also, it’s much, much more common now. But for now, for placenta previa, let’s just stick to this.
So now that we sort of know all these things, I think it’s important to maybe summarize what we think people need to know about placenta previa. And I think the first thing is just, you need to know if you have one or not. It’s really the simplest thing. If you walk out of your 20-week ultrasound and you’re not sure what’s going on, just ask, say, “Do I have a placenta previa?” If the answer is no, great. You basically never have to think about it again, the entire pregnancy. And if the answer is yes, well, let’s be clear. Like, what exactly is it? Did they do a vaginal ultrasound? Do they know precisely if it’s covering the cervix or near the cervix? And if not, that’s something to follow up on and ask, “Hey, like, how do you know I have one if you didn’t do a vaginal ultrasound and maybe let’s figure that out?” I think most people will be doing that already, but it’s good to sort of know what the story is.
Dr. Gupta: Right. It’s definitely good to know. But if you’re listening to the podcast and you’re saying, “I forgot to ask in my 20-week ultrasound,” most of the time your doctor would have told you if you had one. But always good to ask.
Dr. Fox: Yeah, this is something people will clue the patient in on. But sometimes, again, people sometimes don’t always explain our terminology because, you know, we speak in medical talk and we’re always confusing unnecessarily. And frequently, we’ll tell people what we think is very clear and they walk out like, “I have no idea what she was talking about.” [inaudible 00:29:32] I don’t know. And so, if you’re not sure what’s going on and they’re talking about where your placenta is and it’s not clear, ask them to maybe clarify, “Hey, like, is it covering the cervix? Is it near the cervix? What are we doing? How concerned are you?” Those types of things.
And then I think the second thing is if you have one, a good question might be, how likely is it gonna be to resolve? And we could frequently give people odds based on is the cervix the middle of the placenta, we call a central previa where it’s like a smack in the middle, in which case it’s less likely versus it’s just barely covering the cervix. And then we’ll say, “Oh, it’s for sure gonna move. Don’t worry about it.” And maybe the doctor knows maybe the doctor doesn’t know, but people who do this a lot have a good sense of whether it’s probably gonna move or not, because should I expect a C-section at 36 weeks or expect it to resolve? It just sorta changes the tenor of the pregnancy, I think.
Dr. Gupta: I agree. It’s definitely good to kind of get a general idea of how worried your doctor is of whether it’s gonna move or not. For two reasons, most of the time they’re gonna probably say they think it’s likely to move and then you can go home and feel reassured that it is likely to move. And if it’s not likely to move, it’s good to start, you know, kind of thinking in advance of things that you might need to be doing differently.
Dr. Fox: Right. Generally, the things we use to determine as the earlier in pregnancy it is, the more likely it is to move, and how much is it covering that cervix. How much should we call overlapping? So if it’s just barely overlapping and you’re 16 weeks, the vast majority move, whereas if it’s, like, completely overlapping. And sometimes you don’t always know unless you do a lot of complex imaging. Sometimes we’ll do what’s called 3D imaging to see exactly what’s the relationship between the placenta and the cervix. Again, a lot of that is just so we can help predict for her how likely is it to move because I think it’s helpful, but there are ways to look in a very comprehensive way to help predict that for her.
Dr. Gupta: Right, exactly. Doing the different types of imaging or 3D imaging can help in some situations. And then the other way that imaging is very useful is to kind of determine if we think there’s a higher risk for accreta or not.
Dr. Fox: Right. The ultrasound can sort of suggest there is or suggest there isn’t, which is good. And then I think if women, you know, they have a placenta previa and they’re not sure if it’s gonna move and they’re sort of moving along, really the most important variable is are you bleeding or not? And if the answer is no, okay, based on how far you are, you may have to take precautions, you may not. But if you’re not bleeding and you haven’t been bleeding, then everything’s going okay until now, for sure. Hopefully, it’ll continue that way, but you need to sort of have your plan, what do I do if I start bleeding? Which is really important. It’s not being too cautious to just have a plan in place for whatever that is. And so, everyone’s situation is different. You know, do you live alone, or do you have a partner, do you have kids? You know, how far do you live? You know, what kind of work do you do? All these things. It’s just important to have that plan in place is what I would say.
Dr. Gupta: And I often get asked, when am I gonna feel like I have more information about whether or not this is gonna be a C-section or not? And I often tell patients, you know, if we’re diagnosing it for the first time at 16 or 20 weeks, somewhere around 28 weeks I can give you more information. Meaning if it’s resolved by 28 weeks, then it’s a much different story than at 28 weeks if it’s still covering the cervix entirely or close to it. So, 20 weeks is a good check-in point to see, you know, to kind of think about whether or not you’re gonna need a C-section or not.
Dr. Fox: Yeah. We’ll often map out the trajectory. Like, you know, like at 20 weeks it was overlapping the cervix by 1 centimeter. At 24 weeks, it was just at the cervix. At 28 weeks, it’s one cervix away. We’re like, all right, it’s moving a centimeter a month. We have a pretty good sense. You know, in the recommendations, you know, when we diagnose at 20 weeks, you don’t have to look at it again until you’re 28 or 32 weeks. And that’s fine. We generally look earlier, not because it makes a difference in terms of what’s gonna happen, but, you know, if we’re telling women don’t exercise, don’t have sex, and come back in three months, I just think it’s kind to like, let’s check in a month, maybe move by then and you can sort of get back to your normal life.
And it’s one of these things where these recommendations are, yeah, medically, you don’t need to look for two or three months if they’re not bleeding because what’s the difference. But from, you know, just a practical perspective or live your life perspective, it’s nice to know. And also people are anxious about it and, you know, it’s frequently very reassuring to know either is gone or hey, it’s moving in the right direction, I’m pretty confident it’s gonna move. So we tend to look again in a month. I think most people do appreciate that.
Dr. Gupta: Right. And it’s also, you know, of course, if you have spotting and you go to a hospital, the first thing somebody is gonna know is did your placenta previa resolve or not? And so, if you already have that information going in, it does make the first evaluation or triage so much better.
Dr. Fox: Yeah. It’s nice to know where your placenta is when you come into the hospital because it’s hard to do the vaginal ultrasounds in a lot of triage assessments because the probes are they’re expensive, they have maintenance, they have to be cleaned in a certain way. So it’s hard to just, like, have them around. Some places are fortunate to have them. But some don’t and sometimes the only ultrasound you’re gonna get within the first eight hours of admission is an abdominal one and you have to go to, like, the radiology unit or maternal-fetal medicine unit later to get the other one.
Another question I get asked a lot, which is important is for women who have a placenta previa, aside from what we talked about, which is, you know, bleeding and the risk of being admitted and a cesarean and early, is there any other downside to having a placenta previa in a pregnancy? I mean, is there a risk to the baby, or the growth, or anything else to the mother aside from these things?
Dr. Gupta: Right. So outside of that, the really kind of only association we talk about is an association with the babies being what we call growth restricted or a lower birth weight, because there’s some association that if the placenta is a previa in one of these abnormal locations, it can be associated with fetal growth issues. And so, it’s for that reason that usually when we are following a placenta previa, we’re also following the baby’s growth to make sure the baby’s growing okay.
Dr. Fox: Right. And so she’s coming every month anyways, to look at the placenta, it’s easy to measure the baby. And the vast majority of the time, the babies are growing fine. And so, I tell people it’s like on our mind, but it’s not something we’re really concerned about. Our bigger concern is the previa itself, not sort of the effect on the baby. There really is almost usually not affect on the baby. And certainly, then it moves away and that it’s not really a concern. We don’t have to follow people after it comes.
Simi, this is great. What a good review of placenta previa? I appreciate you coming on. Again, if you have concerns about it or questions, this is a really good thing to clarify with your doctor, what’s going on with your placenta and if there is concern or no concern. And again, for the vast majority of people who get told they have this, everything is gonna be fine. You’ll either resolve or you’ll get delivered safely by cesarean and everything’s gonna be okay and you don’t have to start looking at the stuff that happens in 1860 for these women, because that is pretty scary stuff. So great. So thanks for coming up.
Dr. Gupta: Thank you. Thanks for having me.
Dr. Fox: Thank you for listening to the “Healthful Woman” podcast. To learn more about our podcast, please visit our website at www.healthfulwoman.com, that’s healthfulwoman.com. If you have any questions about this podcast or any other topic you would like us to address, please feel free to email us at email@example.com. Have a great day.
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