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Placenta Accreta Spectrum Overview

Author Melissa Malena covers Placenta Accreta Spectrum Overview on BackTable OBGYN

Melissa Malena • Jul 19, 2023 • 134 hits

Placenta accreta spectrum (PAS) occurs when the placenta attaches to a previous scar and the uterus undergoes remodeling as a result. According to OBGYN Dr. Brett Einerson, severe placenta accreta spectrum creates a significant risk of maternal hemorrhage that requires intensive preemptive monitoring. Implementation of this monitoring by specialists poses a challenge to both the patient and physician. Placenta accreta spectrum diagnosis and treatment are often complicated and difficult, requiring early referral to specialist centers. Dr. Einerson’s team attempts to negate maternal risk and neonatal risk by delivering as close to term as possible and extensively monitoring pregnant patients in both outpatient and inpatient settings. This article features excerpts from the BackTable OBGYN Podcast. We’ve provided the highlight reel in this article, but you can listen to the full podcast below.

The BackTable OBGYN Brief

• Traditional grading of placenta accreta spectrum includes accreta, increta, and percreta, indicating increasing depth of placental invasion into the uterine wall. Remodeling of the uterus by the placenta can distort the normal pelvic anatomy, transforming it into a "superhighway of blood flow", posing high risk during delivery.

• Prioritization should be given to screening for risk factors and understanding the patient's risk profile, rather than solely focusing on definitive PAS diagnosis. Physicians should maintain a high level of suspicion in patients with risk factors and should have a low threshold for referrals to specialty centers.

• Placenta accreta spectrum poses a significant risk of maternal morbidity with severe cases leading to ICU admission, massive blood loss and transfusion, bladder injury, uterus removal and even maternal death. Neonatal morbidity is almost entirely related to prematurity, not fetal growth restriction or congenital abnormalities.

• Dr. Einerson’s team follows and recommends a comprehensive approach involving regular ultrasound checks, early involvement of the entire medical team, a low threshold for patient admission in case of bleeding, and aiming for delivery around 34 to 35 weeks.

Placenta Accreta Spectrum Best Practices in Diagnosis, Treatment & Risk Management

Table of Contents

(1) Placenta Accreta Spectrum Pathogenesis, Clinical Stages & Surgical Challenges

(2) Placenta Accreta Spectrum Diagnosis and Early Intervention

(3) Balancing Maternal & Neonatal Risks in Placenta Accreta Spectrum

(4) Placenta Accreta Spectrum Clinical Recommendations & Best Practices

Placenta Accreta Spectrum Pathogenesis, Clinical Stages & Surgical Challenges

Placenta accreta spectrum occurs when the placenta attaches abnormally into the uterus, leading to severe hemorrhaging if forced removal is attempted. Dr. Einerson explains that PAS, which is more common in patients with multiple prior C-sections, occurs in a spectrum with varying degrees of severity. The traditional grading of the condition - accreta, increta, and percreta - indicates increasing severity of placental invasion. However, he highlights that this traditional classification is evolving, with more emphasis now being placed on clinical grades that better reflect the disease's appearance during surgery. Finally, Dr. Einerson elaborates on the remodeling of the uterus by the placenta, and how this process can distort the normal pelvic anatomy, leading to a higher risk of severe complications during delivery.

[Dr. Amy Park]
What's the average parody of the patients, would you say?

[Dr. Brett Einerson]
It's funny because I read placenta accreta studies from other countries and the median number of prior C-sections is sometimes zero or one in these studies from overseas. Our average, accreta patients have had at least two or three prior C-sections. I've had patients who've had 5, 6, 7, 10 babies. Overall, in Utah family size is almost twice as large as the national average.

[Dr. Amy Park]
Wow. Well, tell us what is PAS? What is the nomenclature? How do you even define it?

[Dr. Brett Einerson]
Sure. A lot of probably what we'll talk about today, this is an evolving area, but placenta accreta spectrum has always been known to be this obstetric complication where the placenta attaches abnormally into the uterus and doesn't let go at the time of delivery. And as a result, if you force the placenta to come off when it's attached abnormally, it results in significant hemorrhage that's much worse than it would be if it was uterine atony or some other cause of postpartum hemorrhage.

We think placenta accreta spectrum happens and starts off very early in pregnancy. The placenta probably attaches abnormally very early on in its development in an area that's scarred or damaged within the uterus. Placenta accreta spectrum exists on a spectrum. There are milder cases really where the placenta is just abnormally attached. It may not even look all that different either sonographically or physically at the time of delivery.
Then there's very, very severe cases in which the placenta essentially attaches into the prior scar, totally remodels the uterus, distorts the normal pelvic anatomy, and changes the normal pelvic vasculature into a superhighway of blood flow. In short, it's an attachment problem and it's a remodeling problem. No matter how you think it develops or forms or what it's caused by, the end result is pretty clear. It's a really difficult delivery that's at high risk for massive bleeding.

[Dr. Amy Park]
How do you even describe it in terms of are there grades? I don't know, it's been a long time and maybe things have evolved. I don't think that we just had accreta, increta, percreta. I mean are there stages now or how do you even describe it?

[Dr. Brett Einerson]
This is confusing because it's changing really rapidly over the last three to five years. Traditionally, the way we describe placenta accreta was in the framework of a placenta that's abnormally growing into the wall of the uterus, and so there were different grades. A placenta accreta spectrum which includes accreta or creta, which is the mildest form, where the placenta is abnormally attached but not necessarily invading into the wall of the uterus. Then increta and percreta are progressively worse manifestations of a progressively invading placenta, where the placenta invades further through the wall. In percreta, you can even have an invasion past the serosa into the bladder or into other organs in the pelvis.

That's really the way that the disease has been described since the '60s or even before. The nomenclature didn't really change much for this, which used to be a relatively rare disease through the 20th and into the 21st century. Increasingly, pathologists and clinicians are noting that that description of placenta accreta maybe doesn't capture what the disease looks like in the hands of the surgeon. It may look like that when the pathologist gets a specimen that we've wrestled out of the abdomen and torn out the side wall of the uterus.

In general, the way that the disease acts in the body and at the time of surgery, in my opinion, is that the placenta attaches into a C-section scar, remodels or doesn't remodel the uterus and really transforms and remodels the uterus. We're starting to talk a lot more about clinical grades, what the disease looks like at the time of delivery, if you can actually see it. That's defined by the FIGO staging.

FIGO in 2019 came out with a clinical staging that's FIGO 1, 2, 3, based on the appearance of the disease in utero, with 1 being essentially attachment without other changes. 2 being vascular appearance changes on the outside of the uterus but no placenta extending all the way to the serosa. Then percreta or what used to be called percreta, now stage 3 being placenta that extends all the way to the serosa. You can see it at the time of surgery underneath a thin layer of serosa and then significant vascular changes.

[Dr. Mark Hoffman]
When you say remodeling, can you be more specific or more-- I guess talk to a gynecologist. What do you mean when you say remodeling?

[Dr. Brett Einerson]
That's a great question. The remodeling that we think happens during placenta accreta spectrum is that you've got an embryo or an early placenta that attaches into a very small area of C-section scar or other scar from prior surgery. Those cells that are microscopic at the time of an implantation grow into a full-blown organ, a placenta that has to grow somewhere. In the most severe forms of placenta accreta spectrum, it grows within a C-section scar. That early placenta, which is microscopic or very small, turns into a full organ, the size, you remember placentas from residency, size of a flat volleyball.

[Dr. Mark Hoffman]
I do remember those.

[Dr. Amy Park]:
It's been a minute for me, it's like since 2006 really.
[Dr. Brett Einerson]
It's got to grow somewhere. If it's attached abnormally into a small area of scar, it's going to stretch and distort and grow into that scar, distorting the part of the uterus that it's attached to. Remodeling to me means sometimes you open up the abdomen, what you see is a snowman. You've got the baby in the amniotic fluid at the top and then you've got this placenta that's totally remodeled, the lower part of the snowman or the lower part of the peanut shaped uterus.

It really is, we think, growth within a confined space and lack of freedom for that placenta to develop normally like it should on the side of the uterus. Instead of that, it's growing within a confined space, within the scar remodeling not only the uterus but the parametria and the bladder and the vessels in that area.

[Dr. Amy Park]
I just want to shout out that Brett just published this exact thing in The Green Journal, March 2023. I think you even appeared on a podcast or it was one of the featured articles and there's a journal club. It was really cool and I encourage our listeners to read it because even for me, I'm not an obstetrician anymore, but cool clinical pictures from the time of surgery, imaging pictures, and the pathology. Just mind-blowing paradigm shift in terms of how we conceive of placental-- It's not placental invasion as much as it's the uterine remodeling part that I really thought was very interesting.

The other thing I wanted to ask you about is that, this point brings up doing abstract and video reviews for all of these conferences like SGS and AGL. Treating the uterine niche is so hot, isthmocele, like people are doing tons of it. I've seen lots of different techniques. Section D and C, you can do a resectoscope, you can laparoscopically fix it, robotically fix it. Lots of different ways. I've seen wedge resection. What is your take of the niches and does that work really well? What's the data behind it? Presumably, that's the beginning of PAS. I don't know, tell me.

[Dr. Brett Einerson]:
I love that question in part because it gets at the heart of the work that we've been trying to do including in that study that you mentioned. The way that I have come to think about placenta accreta spectrum is more a disorder of the uterus in which the placenta is not an innocent bystander but the placenta is not the offending organ. To me, the uterus or a defective scar specifically is the issue.

It stands to reason that if we can make a better scar in the first place or fix bad scars that form after prior uterine surgery specifically C-section. Maybe it's a cesarean scar pregnancy treatment or a myomectomy or a prior other intrauterine surgery, it stands to reason that we would reduce the risk for placenta accreta spectrum in the future. Those studies are very hard to do because following people perspectively after those surgeries would still require a ton of people to even get a few cases of placenta accreta spectrum. This continues to be a relatively rare problem, about 1 in 1000 pregnancies we think.

Prospective research is really lacking and very, very hard to do outside of large multi-state even multinational studies. My hunch is that if there is a large keeping niche in the lower part of the uterus that serves as a really hospitable home for a future case of placenta accreta spectrum. There is some data to suggest that embryos may be more likely to implant in a large niche versus just a prior cesarean scar. I think that data are currently lacking to overwhelmingly or full-throatily say, "We should be fixing all of these," or, "Here are the characteristics of niches that we should be fixing."

That being said, people are moving forward full bore. Even in MFM, it's leaching into our world, like what the heck do we do with this preconception consultation that comes with a uterine niche or isthmocele? Are we supposed to be repairing those, resecting those? We honestly don't know. I look forward to researchers informing that question more because in part I wonder are you taking out one scar and adding another? That gives me a little bit of pause.

If you take out a gaping niche and make it a little bit better does that reduce the risk? I'm not sure that it does. I think we need more data. The jury's still out. I'm really looking forward to the collaborations between MIS and REI and MFM and really across the breadth of our specialty to figure this question out because it's an important one. More and more patients with ultrasound being performed preconception and early in pregnancy, more and more at the time we're seeing this and we don't know what to do with it.

Listen to the Full Podcast

Placenta Accreta Spectrum (PAS) with Dr. Brett Einerson on the BackTable OBGYN Podcast)
Ep 25 Placenta Accreta Spectrum (PAS) with Dr. Brett Einerson
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Placenta Accreta Spectrum Diagnosis and Early Intervention

Dr. Einerson emphasizes the limitations of relying solely on ultrasound and MRI, which may be misleading given the high rates of false positives and negatives in real-world scenarios. He advocates for a focus on screening and risk factor assessment rather than seeking definitive PAS diagnosis. He also emphasizes the importance of understanding the patient's risk profile, maintaining high suspicion in patients with risk factors, and a low threshold for referrals to specialty centers. Additionally, early detection and intervention for low-implantation pregnancies, specifically in patients with prior cesareans, act as a significant preventive measure for severe placenta accreta spectrum.

[Dr. Amy Park]
Anyway, I want to circle back to just making the PAS diagnosis. How do you do it? Are there any biomarkers? Are you using ultrasound, MRI? How are you even figuring out early on that they have it?

[Dr. Brett Einerson]
How do we do it is a funny question because my first response is to say very poorly.

[Dr. Amy Park]
Good. There are some acupoints in this question.

[Dr. Brett Einerson]
I think it's very difficult. It's very easy to miss this PAS diagnosis and it's very difficult to know exactly what you're getting yourself into before surgery. I think one of the disservices that our literature has done around this topic is to take highly specialized centers and patients who almost exclusively have extraordinary risk for accreta and get a bunch of ultrasounds and MRIs on it and say, "Oh, ultrasound and MRI are fantastic for making this diagnosis. 90% sensitivity, 95% specificity, positive predictive values and you're perfect."

That's not accreta care. That's not how it exists in the real world, but an obstetrician trying to figure out if they need to make their referral to my center does not have that same specificity and sensitivity of the imaging that they will get in routine obstetric care. It's a really difficult diagnosis to make.

We continue to be surprised when we're wrong about the severity of disease or the presence of disease, even at a busy place that's doing multiple cases a month. I want to just acknowledge that part because I feel like you should have a healthy skepticism about how good your tools are. That's important. I also think that people shouldn't feel bad when they get it wrong. Well, you're going to get it wrong, I'm going to get it wrong.

There's something missing from our current way of making the diagnosis that we haven't yet figured out. Maybe biomarkers will be fixed, but let me give you preamble now, I'm going to actually answer your question, Amy. I think it's helpful to split this into screening and diagnosis.

To me, it's very important for people to think about their role in general obstetric practice or even general ultrasound practice as screening for risk, not making the diagnosis with certainty. To me, it's very important to have a healthy understanding of risk profile, a high suspicion in patients with risk factors and a low threshold for referral to a specialty center for a second opinion.

If you're the average ultrasound practice not connected to a busy PAS center, I think your role with diagnosis really starts with the intake form. Does this patient have risk factors for placenta accreta spectrum? That is at least half the bat. If the person's got two prior cesareans and they have a low placenta, it almost doesn't matter what ultrasound findings you see, that person needs a referral and an expert to take a look at their placenta if it's low over the C-section scar.

To me, as I imagine the future of PAS care, I imagine ultrasound units really being screeners of risk factors at definers of placenta location. I think focusing too much on the individual signs like placental lacunae or myometrial thinning or bulging in the lower uterine segment or absence of the clear space or some of the modern rail signs or some of these really in-depth doppler findings. I think focusing on that is less important than defining the patient's risks and knowing the placental location, and in patients who have risk factors, I think referral on for diagnosis, the next phase, is what should happen.

[Dr. Mark Hoffman]
Who should get early ultrasounds, because in general, folks are getting scans at 18 or anatomy scans rather at 18 weeks. Certainly, people are getting dating scans early, but that's not everybody. Is there a population of patients-- like you said, screening history, who should we be sending?

[Dr. Amy Park]
Do we care about low-lying placenta 10 weeks when people are getting their anatomy screening or do we care about it at 18 weeks because it moves?

[Dr. Brett Einerson]
What's hard about this and you're getting at the reality that we're coming to see which is that the cesarean scar pregnancy and early placenta accreta spectrum are overlapping pathologies that have almost identical risk factors and very, very similar appearances. I have a slide set on cesarean scar pregnancy that basically a lot of them look like mini-accretas at 11 weeks. I'm a definite believer in what T-Board Trish preaches is that most cesarean scar pregnancies are baby accretas, early accretas.

[Dr. Mark Hoffman]
So that’s what I had heard is that that's the accreta before it becomes an accreta. That it's the spectrum of that disease, is that accurate?

[Dr. Brett Einerson]
That's our experience and that's what-- I think the best available case series are demonstrating. What's important about that and why I love your question about who should be referred and when is that there seems to be, in the cesarean scar pregnancy literature, a clear demarcation of beyond 9 to 10 weeks. The chance of hysterectomy in C-section scar pregnancy or early PAS is very high at the risk of less invasive and uterine sparing surgeries is much higher after 9 to 10 weeks.

If the United States had infinite resources, which we often pretend to have when thinking about screening. I would say that patients who have a prior cesarean, as part of their viability ultrasound, should aim to have that done at seven to nine weeks, and that an assessment of presence or absence of low implantation should be done.

Seven to nine weeks, again, I will reiterate, if we had infinite resources and an ability to know people were pregnant at an early age, then I would love for people to have an early assessment of low implantation pregnancy at that time. I still think there's a ton of work to be done on defining what low implantation is, defining what is CSP and what is not. That is not going to be disseminated anytime soon, but I think in the future people are going to recognize low implantation in patients with a prior cesarean as a significant risk factor for placenta accreta spectrum.

One reason that I think it's reasonable to at least consider, if you're going to get a viability to get comfortable with looking at the location of pregnancy in the uterus is that the outcomes are so much better for early treatment of CSP in that window. You can perform D&C or laparoscopic treatment or medical treatment and expect that that person's going to not have a major bleeding event, expect that that person will keep their uterus and be able to use it for a healthy pregnancy in the future.

Whereas if you wait until 11 weeks to get the ultrasound, that's already accreta, and the patient's likelihood of having a pregnancy where they avoid a hysterectomy is very low at that point, is much, much lower. It's possible in some settings but not as likely.

[Dr. Mark Hoffman]
That's my experience too, limited as the MIGS person at my institution for the better part of the decade. I had an MFM who had taken care of one early cesarean scar pregnancy, did a big ex-lap and it was this big and he goes, "That was stupid." Then he called me and said, "I want you to take care of it." I'd never seen one, so I called a bunch of people I knew. It was not a challenging case in hindsight, and having done a few more of those, I would agree they're not super technically challenging cases for those of us that do a lot of laparoscopy but diagnosis is one thing and it's challenging watching those things together.

Balancing Maternal & Neonatal Risks in Placenta Accreta Spectrum

Dr. Einerson states that the main concern for most medical professionals is the risk of maternal morbidity, with severe cases carrying a risk of maternal death due to bleeding. Additional risks include the possibility of ICU admission, massive transfusion, bladder injury, and ureteral injury. On the neonatal side, morbidity is almost entirely associated with prematurity as fetal growth restriction and congenital anomalies are not typically associated with PAS. Dr. Einerson also emphasizes the importance of maintaining a balance between reducing the risk of prematurity and mitigating the risk of catastrophic bleeding events.

[Dr. Amy Park]
That's pretty cool. We've alluded to the education and support these patients need, but what are the health outcomes and their quality of life? Is the main morbidity associated with PAS? Is it maternal? Is it neonatal? Is the most morbidity, neonatal morbidity related to prematurity? How does that all work out?

[Dr. Brett Einerson]
Those are good questions. What I tell patients is that placenta accreta spectrum is a problem that keeps most of us up at night for the maternal morbidity risks. Even in modern cohorts for patients with severe placenta accreta spectrum, so closer to the percreta or the FIGO 3, there's a real risk of maternal death during treatment and usually that's from bleeding. Those occur if you practice placenta accreta surgery long enough, you're going to have a maternal death, unfortunately.

To reassure patients, I tell them that those risks are generally thought to be less than 2% to 3% for even severe cases of placenta accreta spectrum. There's the risk of ICU admission if you get a massive transfusion, bladder injury is pretty common like 20% roughly of cases, ureteral injury may occur in 5% to 7%, and so there's significant surgical morbidity from a maternal standpoint.

The neonatal morbidity is really almost exclusively related to prematurity. That's one of the reasons that international colleagues of mine are really interested in pushing deliveries to later because thankfully, sort of astonishingly, this placenta that's not living where it's supposed to and that looks totally nasty in some cases, is actually doing a really good job of taking care of the baby. Fetal growth restriction is not associated with placenta accreta spectrum like you might think it might be.

Congenital anomalies are not associated as far as we know. To me, that's a further reason that it's not a placental problem. That it's a uterine problem, but that's my soapbox. What I try to give patients reassurance about is that it's our job to figure out the right balance between reducing the risk of prematurity over time and not putting you at too much risk for catastrophic bleeding events. Because the worst cases, the scariest cases, the ones where we bring otherwise healthy people to the brink of death are the ones where they come in and they're one or two or three liters down already and getting massively transfused before we can even get the baby out or start the hysterectomy. The delivery timing question is an important one to keep investigating. For that very reason, we're always, just like my entire job, always balancing what are oftentimes competing maternal and fetal risks. Then I would be totally remiss if I didn't talk about the psychological aspect of this. We have all, until this point, until maybe three to five years ago, almost completely in the literature ignored the psychological toll of placenta accreta spectrum.

Placenta Accreta Spectrum Clinical Recommendations & Best Practices

OBGYNs Dr. Brett Einerson, Dr. Mark Hoffman, and Dr. Amy Park discuss the challenges associated with diagnosing and treating cesarean scar pregnancies. They emphasize the need for more research and clear guidelines for when to intervene. Dr. Einerson particularly stresses early termination in clear cases where the pregnancy is deep within the scar, as these cases have high potential to turn into difficult, and potentially catastrophic, cases. For cases that fall in the gray area, counseling and decision-making become much more complex. Dr. Einerson further outlines the best practices established in their institution, involving a monthly ultrasound, involving all team members early, having a low threshold for admitting patients who experience bleeding, and aiming for delivery between 34 and 35 weeks gestation. Additionally, the team also emphasizes the importance of patient proximity to medical facilities in achieving optimal outcomes and discuss measures to overcome geographical and social barriers. The panel also points to the significant role experience plays in managing these high-risk cases.

[Dr. Mark Hoffman]
It feels like you're watching a fuse on a bomb because you aren't sure what you're looking at but yet waiting longer, as you just told us, dramatically increases the risk to the patient. One of my big questions was how do we counsel our patients? Because sometimes you see a low-lying placenta, a niche and it grows up into the uterus, sometimes it turns out into what we're talking about here today. When do we intervene? When do we take that opportunity at seven, eight weeks to do something knowing that maybe it won't be an accreta?

[Dr. Brett Einerson]
To me, there's a ton of work to be done here. There's some interesting developing criteria for location of the early pregnancy in the start to direct us, but all of that stuff still needs to be validated. We are really oftentimes stuck in the gray, but for the cases that are less gray, for black and white cesarean scar pregnancies that are deep within the scar at less than 10 weeks, my recommendation for patients, because it's so deep in and because the diagnosis is clear, my recommendation to those patients is pregnancy termination. A fair number of my patients don't take that recommendation.

My experience has been, with six or seven cases now over the last five years, that all of those turn into terrible what we used to call percreta or FIGO 3, all of them turn into difficult cases. Some of them result in very, very early deliveries, even pre-viable deliveries. I have had patients who don't proceed with a recommendation, then go on to have a pre-viable delivery, and at that time, 18 weeks, they lose their uterus because there's not good treatment options.
My recommendation for obvious growth into the scar, low implantation, obvious cesarean scar pregnancy in the first trimester is termination of pregnancy by whatever local standard there is. Those standards differ. Sometimes it's injection, here it's suction D&C under ultrasound guidance with laparoscopic backup. That's been super successful for us. To me, that's one case where the risk of proceeding with pregnancy is considerable. The likelihood of taking home a baby that will be live-born and survive is lower and the likelihood of losing your uterus with expected management is close to 80% to 100%.

In the gray zones, it's much harder to counsel patients. If it's on the scar instead of in the niche pregnancy, cesarean scar ectopic at 10 weeks, or if you don't make the diagnosis until 15 weeks, it's very difficult to know what to do. I've had a lot of patients who come to me bleeding at 15 weeks, who look back at their images, they had cesarean scar ectopic, now they've got full blown, bad accreta and they're already bleeding.

I've counseled patients in that time period to have gravid hysterectomy because they're bleeding so much. I've had a few patients make it to viability or beyond in that group, but knowing an individual's outcome is beyond our abilities at this point. If there's not enough cases in the literature, there's not a good enough risk paradigm set up yet to be able to counsel patients well, aside from the obvious cases early on.

[Dr. Amy Park]
That's super fascinating because this whole dialogue about cesarean scar ectopic seems to be, like I said, just so much newer. This was not a discussion when I was a resident. Like I said, so many surgical videos, so much discussion, so much-- there is a gray zone and you've seen this develop over your experience. I'm so appreciative.

[Dr. Mark Hoffman]
And MIGS people and MFMs have to talk to each other now, which is a little uncomfortable at times. It's not great, but we do it. It's what we do for our patients.

[Dr. Amy Park]
Let me ask you about just what have you established in terms of best practices? I know that's an evolving area, but what's the optimal timing of delivery? Are you giving everyone steroids? Do you put them in the main OR instead of L&D, do you position them some way? Do you have a massive transfusion protocol ready? How are you managing all this stuff? Do you have IR and backup? How are you managing these patients?

[Dr. Brett Einerson]
Thanks for asking that. We have a protocol that we put together a couple years ago. It's iterative, it's updated every year basically to try to adapt to the evolving best practices. Our general approach is that we think our best practice based on the current literature and our experience is first of all to, like I said before, to have a pretty healthy skepticism that we are going to know about every case, and as such to overprepare even when we're not sure of the diagnosis and even when we think the diagnosis is more mild.

I can tell you that within our system in the last 10 years, I wasn't here for the whole 10 years, but looking back at some of our worst cases, they were cases of unclear diagnosis. "We're not sure that this patient has placenta accreta. Let's try to pull on the placenta," or, "This looks like a milder case. Why don't we try for uterine conservation or pulling on the placenta?" Those are some of the actual worst cases.

I think optimal care really starts with a low threshold to over prepare. Meaning, having them done at a time when you can have surgical backup, having enough blood available in the room, having the team ready and not just relying on your response to unexpected cases but to over prepare even in cases that are a little bit borderline. That's a philosophical point.

We see these patients throughout pregnancy, we get an ultrasound about every month to take a look at the placenta. In our experience, the placenta doesn't continue to grow into organs. It's established by 20 to 24 weeks how severe it's going to be. Then depending on the individual's characteristics, we start having them see our anesthesiology team to prepare for that. Having them see the pelvic surgeons who are going to be involved in their care. Getting familiar with our labor and delivery triage in case they have a bleeding event. We introduce people to all of the team members who are going to be involved in their care.

For patients who have bleeding during pregnancy, we have a pretty low threshold to admit though, because our experience is that one bleeding event often leads to an unexpected delivery. We have a pretty low threshold to monitor people beyond what we would otherwise monitor people for preview with bleeding. I've had patients, unfortunately, who spent most of their pregnancy in the hospital. Delivery timing, our approach with that is to usually follow the guideline that's put forward by ACOG, which is 34 and 0 to 35 and 6. Although I will say that even the ACOG guideline says that the optimal delivery time is unclear.

Internationally, there are a lot of people who are pushing for a later delivery, 36 to 37 weeks in well-selected patients. In some patients, they have been very stable, they don't have a lot of uterine activity. They live very close to the hospital. Maybe they don't have a placenta previa. They're highly motivated to deliver later. We will aim for 36 to 37 in those patients. We individualize it and if it's a sure case and there's anything that the patients are having in terms of uterine contractions, bleeding at all, we typically aim for that 34 to 35 and 6-week window.

[Dr. Mark Hoffman]
Just hearing you talk, the number of cases you've done, the nuance between each case and how individualized you're able to be with each case, case by case. Like you said, if you're doing a couple of these a year, if you're doing a handful a year, there's no way, and without an abundance of literature, this is where experience can matter maybe as much as in any place in medicine and what we do in obstetrics in general.

Not as much research as we'd like, but in this area, just hearing you talk and how you'd be able to counsel patients, "Oh, well I've been doing this for years. I've seen this many--" Well, I'm going to listen to whatever you say as a patient as opposed to like, "Well we're just going to see how it goes." I'm just getting a window into the value and the power of having a center like yours.

[Dr. Amy Park]
Do you give everyone steroids based on your experience, or obviously if they have a bleeding event or uterine contractility or what have you?

[Dr. Brett Einerson]
I try to save the steroids up until the time that delivery seems fairly imminent. Certainly if somebody comes in at 28 weeks and has a liter blood clot or we’re wondering whether or not they're going to get delivered, they get steroids. Most cases, we hold off until a week or two before delivery. Since we're aiming for that 34 to 35-week time period, it's right at that cusp of traditional antenatal steroids and ALPS. We are typically administering steroids around that 33-week time period if all is going well in their pregnancy.

Mark, I think to add on to what you were saying or to throw in my 2 cents on that, I think for other types of serious health problems, and I think this is a serious health problem, it's evident that you get a second opinion. It's evident to patients and to doctors that you go to the place that does more of them. My dad got cancer living in rural Minnesota when I was a first year fellow. At the risk of offending the University of Minnesota, another healthcare system is like when you get cancer in Minnesota, you go to Mayo. I'm not saying Mayo has something hyper special there, but patients know you have a serious diagnosis to do it to the place that has the name for taking good care of patients.

[Dr. Mark Hoffman]
I'm in Kentucky and I've spent time working in rural Eastern Kentucky. We had a rural eastern Kentucky doc on the show because I think the work that they do is invaluable and not to do anything but to give them credit. That being said, when you're dealing with things like this that are incredibly rare and in your case potentially incredibly catastrophic, volume matters.

In terms of proximity, are you having folks move to Salt Lake City? What can you do to get social support? Because one of the big things I've learned working with the population of patients that live remotely and live rurally, access is-- you can know the right answer, you can check the right box, but if they're 120 miles down country roads away, it doesn't matter that you know the right answer. What measures are you guys taking in Utah to solve some of those social determinants of health, the proximity issues?

[Dr. Brett Einerson]
Yes, so thank you for that. The best study on how unpredictable delivery can be for patients is, I think, comes from Baylor where they show that about 35% to 45% of patients, depending on the year, delivered before their expected delivery time, placenta accreta spectrum and many of them weeks and weeks beforehand. It's a particular challenge for those of us taking care of accreta to not only be ready 24/7 but also to not take substantially worse care of our patients who live four or five hours from the hospital.

That's inequitable. If we don't have systems set up to help those patients financially, then we're being inequitable with our care. It shouldn't be the happenstance that if you live in my area code that you get much better care than if you live in rural Idaho. What I will typically do when we make the diagnosis, oftentimes in the middle of the pregnancy, is to have a conversation or communication with the home doctor and give them the expectations for what things I want to see the patient for and do co-management up until about 30 weeks. Then sometime between 30 and 32 weeks, I ask patients who live more than 45 minutes from the hospital to make arrangements to come to live in Salt Lake City.

For some patients that means a family member. There's a lot of large families in Utah, but for many patients, that's taking up residents at Ronald McDonald House. We, unlike a lot of other centers that I've heard from, actually have really amazing support for pregnant people at Ronald McDonald's Center.

[Dr. Mark Hoffman]
I was going to ask because I don't think of the Ronald McDonald House as being a place where people stay who are still pregnant. Talk about what makes that special or how that came to be.

[Dr. Brett Einerson]
I think it existed prior to my coming onto the scene in Utah. It wasn't something that I had to set up personally. I think it was a realization on the Ronald McDonald House that so many patients, whether it was due to a complicated fetus or complicated mom, were going to end up in their hands anyways. We're not as landlocked in Salt Lake as we were in Chicago where I know that Ronald McDonald had maybe a little bit stricter criteria for who could be there. We have, I think just out of good relationships and good luck, had the good fortune of Ronald McDonald being able to house these patients with placenta accreta spectrum or other anticipated fetal and maternal prematurity-related needs.

Its prematurity is the key that unlocked our ability to have patients around Ronald McDonald, and as long as they have another adult with them, they're able to stay there. For patients who don't, and a lot of them don't, our hospital has arranged for basically sliding scale type housing at one of the very local hotels or will set them up in an apartment depending on their unique needs. For patients who prefer something different, I've had patients who do other things like stay in their RV at an RV park and it's 20 minutes from the hospital.

Podcast Contributors

Dr. Brett Einerson discusses Placenta Accreta Spectrum (PAS) on the BackTable 25 Podcast

Dr. Brett Einerson

Dr. Einerson is an assistant professor of OB/GYN in the division of Maternal Fetal Medicine (MFM) and Director of the Utah Placenta Accreta Program at the University of Utah.

Dr. Amy Park discusses Placenta Accreta Spectrum (PAS) on the BackTable 25 Podcast

Dr. Amy Park

Dr. Amy Park is the Section Head of Female Pelvic Medicine & Reconstructive Surgery at the Cleveland Clinic, and a co-host of the BackTable OBGYN Podcast.

Dr. Mark Hoffman discusses Placenta Accreta Spectrum (PAS) on the BackTable 25 Podcast

Dr. Mark Hoffman

Dr. Mark Hoffman is a minimally invasive gynecologic surgeon at the University of Kentucky.

Cite This Podcast

BackTable, LLC (Producer). (2023, June 15). Ep. 25 – Placenta Accreta Spectrum (PAS) [Audio podcast]. Retrieved from

Disclaimer: The Materials available on are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.



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