Dr. Warner Huh (Host): Hello, everyone. This is Dr. Warner Huh, the Chair of Obstetrics and Gynecology at the University of Alabama in Birmingham. And I would like to walk you to this monthly episode of Women's Health with Dr. Huh. I'm excited about the summer officially.

So, we're going to talk about something I'm pretty sure most of our listeners know very little bit about, but the topic is exceptionally important, and that topic is placenta accreta spectrum. We call it PAS for short. And so for our listeners, we're actually going to do two separate podcasts on this. One is a little bit about what PAS is, how it's diagnosed, and how we manage it. And then, the second part is going to be dedicated solely to treatment, particularly the surgical treatment of PAS. So, I think this is going to be interesting.

We wanted to keep this at a high level, but I think this is a really important topic for the audience to kind of understand because the significance of it is pretty dramatic as you'll hear shortly. So, I have two great guests with me today. First, Dr. Akila Subramaniam, who is our Division Director for Maternal Fetal Medicine here at UAB, and she's also the Fellowship Director for the Maternal Fetal Medicine Fellowship in our department.

And then, our other guest is Dr. Haller Smith, who is an Associate Professor within the Division of Gynecologic Oncology. And we'll explain shortly why a gynecological oncologist is on this podcast, but she's also the Fellowship Director for the Fellowship Program for Gynecologic Oncology in our Department. So, I'd like to welcome both of you to the podcast today.

Dr. Haller Smith: Thanks for having us.

Dr. Akila Subramaniam: Thank you.

Host: Okay. So, let's just dive into it. So, I've thought about doing this podcast for a while and I know the two of you have extensive experience over many, many years on placenta accreta spectrum. So, maybe start with you, Akila, and just maybe you can share with the listeners what exactly is placenta accreta spectrum and maybe comment on the risk factors and why pregnant women should care about this.

Dr. Akila Subramaniam: Yeah. So, I think, first thing to consider is this is a spectrum of disorders, but it really boils down to that the placenta is a little stuck to the uterine wall. So, for those of you who might be a little bit unfamiliar with this, the placenta is also known as the afterbirth. It's what actually connects maternal blood circulation to the baby to nourish the baby inside the womb. And so, typically, what happens after delivery is after the baby is delivered, the placenta should spontaneously detach as the afterbirth. In the placenta accreta spectrum, that placenta doesn't detach and it's abnormally adherent. So, you may also have heard it called adherent placenta. That placenta is stuck to the uterine wall, which can cause a number of problems with delivery and immediately postpartum, which is why we're here talking about this today.

In terms of the risk factors for this, the simplest one is the number of C-sections. So, you may have heard your OB-GYN talk about trying to avoid multiple C-sections, but there's a considerable amount of data out there that the higher the number of C-sections you've had, the higher the risk of having a placenta accreta spectrum disorder. Some other risk factors that also are there include having multiple pregnancies. So, people who have six or more pregnancies, have a higher risk of placenta accreta. Also, instrumentation of the uterus, so not just a cesarean delivery, but things like dilation and curettage is hysteroscopies and polypectomies inside the uterus. And finally, one of the things that we're seeing more and more in the current population is an increased risk factor of PAS with in vitro fertilization, so IVF pregnancies.

I think the last big risk factor is where your placenta is located. So even if you've had multiple surgeries, if your placenta is on the front of your uterus, as is most commonly the back or the top, that risk is much lower for PAS than if your placenta covers the birth canal, which is what we consider a placenta previa. But these are the biggest risk factors and, like I said, the one we talk about the most is prior surgeries, especially cesarean deliveries.

Host: So, I thought maybe you could comment-- like, so when I was a resident many years ago, we would see occasional cases of placenta accreta spectrum. But am I incorrect in saying that it seems that the incidence of this has gone way up in the last decade or so? That's what it feels like to me.

Dr. Akila Subramaniam: Yeah. And I would say that's very true. I think if you look at the rates of the placenta accreta spectrum disorder, it sort of correlates with the same timing as which people decrease the likelihood that they were having a vaginal delivery after cesarean. So, you actually see those two things highly correlated. So, for a lot of patients who've had one cesarean, a lot of times they can have a normal trial of labor afterwards. But there was some data, some challenges with anesthesia where the rates of that being offered were significantly lower and that actually correlates with this increased risk of placenta accreta because we have a number of patients who've had repeat sections.

I think also alongside that is there are a number of providers who are in smaller hospitals that don't have all of the resources needed to support a trial of labor after cesarean. So, there's just a higher rate of repeat cesarean now in this country than previously, which then correlates with the increased risk of PAS. I think that combined with the higher rates of IVF is responsible for what we're seeing.

Host: So Haller, let me ask you this question because obviously we started off the conversation and the topic with placenta accreta spectrum. So obviously, the listener was probably wondering why is it to call the spectrum? So I thought maybe you could define that for the audience, but also more importantly, you know, why should pregnant women be aware of this and why is this ultimately important?

Dr. Haller Smith: Yeah. So, that's a great question. So, we call it a spectrum because it's not just one disorder, but it's actually a range of findings that vary in severity. So, you can have a placenta accreta, which essentially just means that the placenta is abnormally attached to the uterine wall. And then, there are other increasing levels of severity where the placenta is actually growing into, or actually all the way through the wall of the uterus and sometimes even invading into surrounding structures.

So, you may wonder why a GYN-oncologist is even involved in this conversation. But in some cases, these placenta accreta spectrum cases can behave almost like a cancer and that the placenta can grow all the way out of the uterus and into the bladder, for example, which will be the most common other organ that's involved.

Host: So, there's a spectrum. So obviously, it's essentially the invasiveness of the placenta that basically almost burrows into the wall of the uterus. And it can go through the wall like you're saying. And again, to kind of recapitulate what you just said, it could actually go into the bladder, which is--

Dr. Haller Smith: Yeah, it can. So, it can grow into really any organ that's immediately around the uterus, but the bladder sits right on top of the front wall of the uterus, and usually is right where we make the hysterotomy or the incision to deliver the baby. And so, that's the most common organ. Because the wall tends to be thin there, the placenta can actually grow through that prior scar and into the back wall of the bladder.

Host: Okay. So i'm pretty sure our audience can connect the dots and say this sounds all really bad. So, what should pregnant women be aware of and what's the significance of this accreta, and potentially going to the bladder? Like, why does that matter at the end of the day to the individual pregnant patient?

Dr. Haller Smith: So, these disorders can be very dangerous for patients, and I think it's really important to know ahead of time. So, we want to identify this early so that patients, and their care team are prepared to handle the potential complications of these deliveries. And I think the main risk in these cases are not necessarily risk to the baby, but risk to the mother once the baby has been delivered. So if we identify one of these disorders, the treatment is almost always a hysterectomy at the time of the delivery or the C-section. And a hysterectomy at the time of a c-section is much different than a regular hysterectomy because of the increased blood flow to the uterus during pregnancy. And also because the placenta can invade into these other organs, it can really distort the normal anatomy and make these cases really challenging.

The biggest risk to patients other than the loss of future fertility, which is obviously a really big deal, is actually a very significant risk of hemorrhage. And so, that's the main thing that we want to make sure that we're prepared for and that we counsel patients about ahead of time. So, these cases can be associated with very significant blood loss in a high likelihood of needing what we call a massive transfusion protocol. And so, I think it's very important to be sure that these patients are identified early and are delivering in a hospital where the blood bank has the capability of handling a massive transfusion protocol, and where you have an entire care team, including anesthesiologist and surgeons that are capable of managing the potential effects of that.

Host: And we're going to get into that later on. And this is the exact reason, and you answered the question perfectly, which is why we're talking about this today, is to drive some additional awareness for particularly pregnant women. Because, as we mentioned, we see the incidents increasing, so they're more new cases and these are fairly morbid cases, like you said. Like, I mean, my experience and I know that a lot more of these, we have patients where their entire blood volume has to be replaced because there's such a significant hemorrhage.

And I wanted to pass that on to the audience so they understand the significance of this. So, let's kind of repivot back to you, Akila. So, how is this diagnosed? Because I'm pretty sure individuals like, well, how do you diagnose this? And is there a way to diagnose it accurately? What studies are used? So if you could just comment on that.

Dr. Akila Subramaniam: Yeah. I think that when we are talking about diagnosis, the first thing is having a good screening tool and suspicion that this is a possibility. So, for patients when going in to see your doctor, if you've had multiple C-sections and your placenta is low-lying or covering the birth canal, that should ring a kind of a little bell in your head to say, "Hey, I need to see what this placenta looks like."

In terms of the best diagnosis modalities, we typically use an ultrasound. So, it's been shown repeatedly in studies that an ultrasound in the hands of someone who has expertise in placental imaging is about 90-95% accurate. I know people will ask, well, what about an MRI? There have been a lot of studies that have shown that an MRI doesn't add additional accuracy to an ultrasound in a good center with experience and tends to overcall some of the findings. So, we've seen in our practice MRIs talking about placentas invading nearby blood vessels and all kinds of different organs and the patient is relatively stable. And then, later we go in there don't see those things. So at the end of the day, the ultrasound is the most sensitive and the most specific for being able to diagnose placenta accreta.

I think one thing that's really important is that when we think about placenta accreta, these are mostly histological diagnosis. So, this is done under the microscope by the pathologist, meaning, you know, we can give an accurate assessment of risk. We think this is a placenta accreta, but we're never going to really know with a hundred percent certainty until we go into that delivery. And in that case, you know, sometimes we go into the delivery, start the cesarean delivery, and then we can see the placenta coming out. So if we see that, we have a pretty good idea and can diagnose a placenta accreta at that moment. But then, there are going to be other patients where, even after you do the delivery, the placenta may partially come out or not come out. And then, it's going to need to be looked at at the microscope to diagnose the type of accreta spectrum disorder it is. So at the end of the day, diagnosis is really at the time of surgery or even when the specimen is looked at, but the ultrasound is the most key element of making that diagnosis.

Host: And just for clarity purposes, it is safe for pregnant women to undergo an MRI. Is that correct?

Dr. Akila Subramaniam: Correct. So it is safe to go undergo an MRI. Typically, what we do is we don't use the contrast. So, we do MRIs all the time, especially if they're needed. If your provider suggests you get one because they don't have that ultrasound expertise, it's very safe in pregnancy.

Host: Okay. So then, let's go straight to, let's say you have a pregnant patient who has a strongly suspected placenta accreta. What happens next? I'd be love to know from both of you, like, what happens at this point? What kind of counseling? What do you tell patients? What should they expect? I think is really important for us to discuss this.

Dr. Akila Subramaniam: Yeah. So when we see patients in our clinic, the first thing we do is assess. You do an ultrasound. Usually, it requires a transvaginal ultrasound to characterize the placenta. And this gives us a good assessment of how high of risk is it for a PAS, and potentially how extensive. And so, that severity, or looking at the severity, or estimating the severity on an ultrasound kind of helps us stratify patients into one of two pathways in terms of management. So if a patient has a very low risk of PAS, or it doesn't look like it involves extensive external organs or the lower uterine segment is appropriately shaped. Those are cases that we can follow sometimes to about 36, 37 weeks and deliver on our Labor and Delivery Unit.

There are going to be these other cases where we look at them and we can tell it's not just an accreta, it's probably an accreta or a percreta, some of the more severe types of PAS, and potentially have bladder involvement. And in those cases, because of the potential morbidity associated with a hysterectomy. That is when we get our GYN-Oncology colleagues, like Dr. Smith, involved to help us with the surgical planning, as well as the surgical procedure.

Host: Okay. And to be clear, there are going to be some patients with suspected PAS going into a C-section that may not have PAS at the end of the procedure. Is that correct?

Dr. Akila Subramaniam: That's correct. I mean, so there are going to be some patients-- I think in our internal data, it's less than 10% of patients that we think have a high suspicion of PAS and their placenta just comes right out. And it goes the other way too. I think there are patients that we look at and say, the placenta looks reassuring, and then we get into the OR and we're not right, with about 10% as well. So, it can go either way, which is why I think it's always important to tell patients in this case that we aren't going to know with a hundred percent certainty until that point. But because of the morbidity. It's important to plan for all of the different contingencies that could happen.

Host: Going to you, Haller. So, tell me a little bit about your discussion with the patients. So what do you tell them as part of the pre delivery, pre-surgical counseling? What kind of conversations do you have with the patient?

Dr. Haller Smith: So typically if the patients are seen by Akila or one of her partners and identified as having a high risk of a placenta accreta spectrum, and especially if they're worried it's one of the more severe versions, they usually get sent to me or to one of the other GYN-oncologists on the PAS team for a preoperative appointment and counseling. And I think it's really important just to have the opportunity to know the patient and do some of that counseling myself so that they know what to expect ahead of time.

So like I already mentioned, a hysterectomy at the time of a c-section, and especially a hysterectomy for one of these potentially severe PAS cases is very different than what their experience would've been for a prior C-section. So, these can be really big surgeries. They're some of the most challenging surgeries that we do, even as cancer surgeons. And I think these surgeries can be associated with a really high risk of complications and even a risk of death for patients. And so, I think it's important just to have the opportunity to really review those risk and answer any questions. So, I usually at that appointment just sit down with the patient and talk to her about the type of incision, which is often a vertical or up and down incision for these cases as opposed to more of the bikini line incision that we often use for C-sections. And that's just to improve exposure.

We talk about the high likelihood of hysterectomy and the implications for that. So we plan to leave the ovaries, but the uterus and cervix are often going to be removed, at the time of these procedures. And so that definitely has implications for future family-building goals. I think it's important to talk about the risk of blood loss. And again, it's not uncommon for patients to lose their entire blood volume in these cases. And there is a fairly high likelihood of needing to go to the ICU postoperatively. I would say in cases that Akila feels like have a high likelihood of being the more severe ends of the PAS spectrum, the likelihood of bladder injury is probably close to 40 to 50%, which means that the patient may need to go home with a catheter for one to two weeks after delivery.

And so, I think it's just really important to make sure that everyone has a clear understanding ahead of time of what those potential risks are and how we're going to do the best we can to avoid those things.

Host: Yeah, I mean, I guess the bottom line is that you're saying it's a huge surgery.

Dr. Haller Smith: It's potentially a huge surgery.

Host: Right. And obviously, one in which, you know, the patient may lose their uterus as a consequence. But there are a lot of things that could happen during the course of that surgery. And for our listeners, again, there's a ton of blood supply that goes through the uterus, particularly at the end of the pregnancy. And so, the risk of blood loss is enormous. But, no, just a lot going on. So, I can imagine the conversation can be somewhat shocking to patients because they don't realize the gravity of the situation.

Okay. So, we talked about this briefly, but I would love for one of you, or both of you to comment on sort of the unique team-based approach that we have in this department and at UAB. Years ago, it was sort of like if the patient came in and they had accreta, it was a big emergency and lots of morbidity, complications, but your team has done an amazing job at coordinating care and I'm very confident that the outcomes are substantially better, because we can do these cases under a more controlled set of circumstances.

But I would love for both of you to comment on just your experience with the team-based approach, why you think that's important, but to comment on what one of you mentioned, which is why some of these cases really do need to be done at a tertiary care medical center. I think you said it, Haller, making sure that there's enough blood to be given because not every community hospital has enough blood, but I would love for you both to comment on that.

Dr. Akila Subramaniam: Yeah. So, I think that there's a lot of data out there that shows that, in very complex medical care cases, whether it's surgical or not, a team-based approach is always better because it allows people with their unique set of expertise to work together. As you'd mentioned in the past, patients just came in and got their surgery by whoever was there. And in the last probably about seven to ten years, we've assembled this team, bringing together some unique skill sets. In terms of the team-based approach, it allows us to do a couple things. I think, despite like how morbid this is and the potential risks, it is still childbirth. And so, it is a unique time for patients and trying to be able to stratify, hey, who's a lower risk case and can have kind of a normal childbirth experience versus who cannot I think is really important. And that involves communication. It's in communication between me and anesthesia, me and Dr. Smith's team.

And having that team-based approach allows us to take an individualized approach to each patient to kind of meet their goals in the safest way possible. I think in the past we just kind of did things all the same way. I think with all of our unique areas of interest and we can really work to help the patient's experience using this team-based approach in addition to improving some outcomes.

Dr. Haller Smith: I would totally agree with all of that. And I think there actually is good data in the placenta accreta spectrum disorders, in particular that a team-based approach improves outcomes for patients. So, having a team of people that do these cases all the time is associated with lower morbidity, less blood loss, lower chance of an ICU stay, and a lower risk of death from complications of some of these things. And so, I think we have a relatively small team of surgeons that do all of these cases. So again, these can be really challenging cases. So, we want to make sure that the people that are doing them have experience in navigating some of the complications.

And I think the other great thing about the team-based approach is that it just allows us all to be prepared ahead of time. And I think that's something that's also really critical. And that the anesthesia team prepares differently and has different IVs and different lines in place to help keep the patient safe and monitor her if they know that we're at risk of having significant amount of bleeding and we can have blood already on standby and available so we're not scrambling to find blood that's appropriately matched to the patient.

And so, I think the team-based approach has really been huge. And I think looking at our outcomes of these cases, they're very good in terms of the surgical outcomes for these patients.

Host: I'm listening to you guys talk, and then I'm just recalling a lot of events in my career where I get called into these emergent PAS cases. And there's nothing more unsettling than having to do an emergency life-saving hysterectomy on a patient that you've never met before. They have no idea that you're ending their fertility. They're getting tons of blood. And it's supposed to be a special time because they're delivering a baby, but you're literally trying to rescue an individual's life. And I think what's game-changing is that you guys have done it under much better controlled circumstances. Like you said, Haller, the data speaks for itself, but I think our experience here is actually very much consistent with that as well.

So, Akila and Heller, I really appreciate both of you taking the time to come in and kind of speak on this topic. I think it's really important. I'm not sure there's as much awareness in the general public as there needs to be, but I think you guys have done a fantastic job kind of mapping out highlights in terms of what pregnant women, but also their partners and the general public need to know about PAS.

So again, in closing, I like to thank Dr. Subramaniam and Dr. Smith for sharing their thoughts and really kind of giving you guys like a primer on PAS or placenta accreta spectrum. And as always, please rate this podcast and we welcome any comments, particularly on topics that you're all interested in. And for more information on women's health services that UAB provides, please check out uabmedicine.org. And until next time, thank you. Have a great day. Enjoy the beginning of summer, and peace out. Bye-bye.