Thinking About Ob/Gyn
A fresh and evidence-based perspective of all things related to obstetrics and gynecology. Follow us on Instagram @thinkingaboutobgyn or visit thinkingaboutobgyn.com for show notes and more.
Thinking About Ob/Gyn
Episode 9.7 OB Triage Essentials (plus The Pitt)
This episode features our favorite podcast ninja, Dr. Maddie White. She and Howard discuss how medical dramatizations misrepresent obstetric emergencies (yes, we are watching The Pitt). Then, we dissect evidence-based approaches to common triage scenarios including labor evaluation, rupture of membranes, and preterm labor assessment.
• Television shows like "The Pitt" and "ER" portray shoulder dystocia and postpartum hemorrhage inaccurately, lacking proper urgency and technique
• Hospital-based labor triage often costs approximately 10 times more than office-based evaluation, often without clinical benefit
• Understanding pretest probability fundamentally changes how test results should be interpreted for suspected rupture of membranes
• Most expensive tests like Amnisure (>$500) provide minimal additional value over traditional approaches when interpreted properly
• Evidence doesn't support routine use of fetal fibronectin testing in preterm labor evaluation
• We discuss universal cervical length screening for prevention of preterm labor in the midtrimester and later in pregnancy for evaluation of threatened preterm labor
00:00:53 Critiquing Obstetric Emergencies in TV Shows
00:10:13 Proper Management of Shoulder Dystocia
00:14:52 Postpartum Hemorrhage Management Approaches
00:19:59 Evaluating Term Labor Complaints
00:25:35 Rupture of Membranes Testing Strategies
00:34:12 Understanding Test Probability and Performance
00:42:26 Cervical Length Screening Evidence
00:51:23 Preterm Labor Triage Tools
01:00:23 Concluding Thoughts on Evidence-Based Practice
Follow us on Instagram @thinkingaboutobgyn.
Welcome to Thinking About OB-GYN. Today's episode features Madeline White and Howard Harrell discussing common OB triage approaches.
Speaker 2:Dr Harrell.
Speaker 3:Maddie.
Speaker 2:What are we thinking about on today's episode?
Speaker 3:Still with a Dr Harrell, I see huh.
Speaker 3:Well, I'm still a resident, so Still with a Dr Harrell, I see. Well, I'm still a resident, so All right, true that? Well, let's talk about some resident stuff. Then, For the listeners, maddie is our mysterious podcast ninja that we talk about sometimes, and she's an OBGYN resident and we're going to have her on a few times to talk about some things that may be more interesting to residents but really are interesting to anybody. A lot of the things that are very basic, I think we all take for granted and don't talk about in a systematic and formal way. So we're going to get into some of that.
Speaker 2:Well, I came with lots of vignettes and lots of questions, so I hope you're ready. I am ready, but first we have to talk about the Pit. I know you've been watching it. Oh yeah, I've been watching and sometimes it feels a little too real.
Speaker 3:Yeah, Well, finally in episode 11, they had the full on obstetric emergency scenario play out.
Speaker 2:Yeah, and everyone at work knows how I feel about it because I've talked about it every day, so they've basically been toying with OBGYN topics all season. There's a storyline about a teenager seeking abortion care, and then there was the patient who was one week postpartum and came in septic after she had been sent home. About a teenager seeking abortion care. And then there was the patient who was one week postpartum and came in septic after she had been sent home about a few hours earlier with a UTI diagnosis. And then, of course, dr Collins has a miscarriage while she's working.
Speaker 3:Right, and for listeners who don't know, the show follows a single ER shift, sort of hour by hour. Each episode's an hour of real time, kind of like they did on 24 many years ago. So they're packing a whole bunch of stuff into one ER shift.
Speaker 2:Yeah, and then finally, in episode 11, there's basically the obstetric trifecta, which is a precipitous labor with a shoulder dystocia. She then has a postpartum hemorrhage, and all of this, of course, is managed by the ER doctors.
Speaker 3:Yeah, in that sense it was giving ER a little bit for me In episode 19 of the first season of ER many years ago. Some people remember they have this patient, they induce a patient who has a clamps in the ER and of course the OB doc is nowhere to be found. They page all the time. Nobody shows up. The OB resident, I guess, is just too busy to bother with some pregnant woman in the ER.
Speaker 2:Yeah, and L&D is full or something, so they conveniently can't send her up.
Speaker 3:Right, and they had some excuse for doing this whole induction down in the ER. Well then, they have a shoulder dystocia and Dr Green decides that he has to do his Avenelli while the patient's seizing at the same time.
Speaker 2:Yeah, so let's go through that whole thing real quick. So there's supposed to be fetal distress. So Dr Green, the ER doctor, puts on forceps and he cuts a median episiotomy. Then once the head is out, he recognizes the shoulder dystocia. So they put her in McRoberts. He asks Carter to push, but he's giving fundal pressure. So Dr Green tells him to move his hands down to give suprapubic. He's then using his hands like he's palpating, he's just laying them on her belly, and so he instructs him there. He then, dr Green, tries to do a wood screw maneuver, but first he extends the episiotomy because of course they had already cut one. Then I guess that doesn't work. So they try to deliver the posterior shoulder and then Dr Green finally decides to do a Zavinelli, and so it's about 75 seconds from the head being out until he calls the Zavinelli.
Speaker 3:I have to say for a resident, you seem to have a lot of time to watch TV.
Speaker 2:Oh right, listen. We're not going to talk about who's working more hours right now.
Speaker 3:All right, it would be a competition though. Yeah, okay, yeah. So they move her to the trauma bay and then Green intubates her. Her blood pressure is super high. They give her mag, they give her hydralazine. Then they do this really amateur hour, cesarean. He's trying to remember if he's a med student, I guess how to do a C-section. They debate where they should make a bladder flap and all this stuff, and now he does this deep arrest, cesarean. They then decide she's abrupting, the mom is crashing, someone pulls the baby out, they make a big deal of like suctioning the baby's nose and then she starts bleeding out, of course. So he has Carter put his fist on the aorta while he intubates the newborn.
Speaker 3:Anyway, long story short, the OB shows up, scrubs in, can't save the woman's life, yeah. And I think the other important detail is that Dr Green had missed that the patient had preeclampsia before. And then this case and a subsequent lawsuit that Dr Robbie or Rabinovich on the pit. And a woman comes into the hospital. She's grabbed a three pair or two. She's a gestational carrier for a gay couple and she's crowning as soon as they put her into the room. And Dr Collins who, as you mentioned, just had her own miscarriage while working, is ready to do the delivery, and then young Carter, or now Robbie, is the attending.
Speaker 2:Yeah, and of course, since it's on HBO Max, they show this delivery without any censorship, which is why we love HBO Max. The head comes out, it doesn't deliver, and then it gets sucked back up in this very dramatic way so that they can show what we call the turtle sign.
Speaker 3:Right, it went so far back in. I think at that point I would have done a Zaffinelli like hey, it's already back in there. That was quite a turtle sign.
Speaker 2:Yeah. So then they asked for the fetal monitor to be brought down and they tell her that she has a shoulder dystocia, but there's nothing to worry about and there's absolutely no sense of urgency whatsoever. She's also sitting almost completely up straight in the bed during all of this. They do some deep breathing exercises. That's at least 20 seconds. Then they do the McRoberts while they coach the mom in breathing exercises and there's all this sorts of slow, calm explanations for each thing that they're doing. No sense of urgency whatsoever. And so then, finally, robbie does super pubic pressure, still with her sitting stark straight up in the bed.
Speaker 3:Right, and that definitely was that flashback scene to the ER, because the same actor, noah Wiley, does the same super pubic pressure in the same ways he did it on the ER and meaning it was done very incorrectly. They also I read an article about this, about how they actually filmed it, and I think they had her sitting up in the bed because they made like this silicon mannequin and they had puppeteers actually pushing the baby out on the other side and so they just the actress had to actually stand. They really couldn't figure out a way to make her lay back. So I think they know she should have been laying back, but just the mechanism of how they constructed that to show the delivery and all that they could, she had to stand up. Essentially.
Speaker 2:Yeah, I see you're trying to make me feel less peeved about the fact that she was sitting straight up, but that's fine. They also keep encouraging the mom to push with each maneuver, and so meanwhile the labor and delivery nurse has finally brought the fetal heart monitor down. She's originally reassured them. They actually say it's been about two minutes since head delivery and the nurse tells them that the fetal heart rate looks great. But then she tells them after the McRoberts fails that there's a late decel. And then everybody gets super excited because of that.
Speaker 3:Right, yeah, robbie takes over because of the late decel. Now there's a sense of urgency. I can tell you, though, that I've never in my life been managing a shoulder dystocia, and I was thinking what's the heart tones right?
Speaker 2:now.
Speaker 3:I will say that, like I like to have a, I would have a sense of awareness of what the fetal tracing has been like leading up to the shoulder dystocia. Because if you were already dealing with a baby that you're worried about the reserve because of tracing issues, you're probably going to shorten the timeline of anything you're going to do. There's more urgency there and you're worried more about resuscitation as opposed to a baby that's had a great tracing and has a lot of reserve. But the whole thing that they're finally upset because there's been a late and now it's an emergency. I worry about that giving patients a false sense of what's going on during a shoulder dystocia. But anyway.
Speaker 3:So yeah, now Robbie has a sense of urgency, puts on a gown and gloves, calls for NICU. At the two minute mark he draws up lidocaine to prep her for an episiotomy. I think he starts that at about three minutes and so he tries to then deliver the posterior arm. They actually announce on the show and a nurse does. I think that it's been three minutes. Well then the OB waltzes into the room, she meets everyone the mom, the two dads and she builds rapport and is calm and is getting to know everyone and stands by calmly almost four minutes into a shoulder dystocia, offering no advice, as Robbie then attempts to do a woods corkscrew.
Speaker 2:Yeah, and so it's been about four minutes total If you look at the time from when they announced the three minutes. And then the baby coming out and so the baby requires resuscitation, which is very dramatic. The one minute Apgar is about one, and then it just instantly cries at about the one and a half minute mark and then, of course, while they're all chit-chatting and cooing over the baby, there's no postpartum pit going and then naturally she decides to hemorrhage.
Speaker 3:Right and once again no OB around. Just so we know, the OB was there for like a minute and then waltzed out of the room so that they could manage the next emergency Gives OBs a sort of a bad rep here.
Speaker 2:Yeah, there's nothing we love more than waltzing into a room and then waltzing right back out of it. The placenta then delivers and she's just pouring out blood. The men are doing skin to skin, while she's losing about three liters in a couple of minutes. They start a second IV. They give a liter bolus first thing. Dr Collins then decides to do an anatomically incorrect bimanual massage. They then decide to give the Pitocin, they give 800 of sublingual meso and then they give TXA all at once. They also start the massive transfusion protocol. They are supposedly, in this time, checking for lax and retained products. I would hope, because you don't really see them doing it. And then they gave hemobate and finally they placed a Bacri, and then, of course, everything is perfect.
Speaker 3:Well, it seemed very much to me like the script writer had no idea what he was talking about, but maybe looked up online. The management of shoulder dystocia, the management treatment for postpartum hemorrhage.
Speaker 3:It really is a good show, but the medical consultants clearly are not obstetricians. But it's also a reminder to me that knowing the ingredients of a cake is not the same thing as being able to bake a cake. I know it's a show and everything's contracted in time and they have logistical issues like that mannequin they have to work around and they also need everything to resolve around the central characters, who are ER docs, not OBGYNs, that waltz in deus ex machina to fix everything. But there's just a lot wrong in both that ER episode and in this episode of the Pit.
Speaker 2:I'm sorry, what was that word that you just used?
Speaker 3:Deus ex machina. It's a Latin phrase. It means God descends down and solves your script problems in the theater world.
Speaker 2:I'm sure all the listeners knew that as well.
Speaker 3:All the theater majors are with me.
Speaker 2:Okay. Well, the episode of ER, I will say, did a much better job with the timeline of things. So literally from the time he recognized the shoulder dystocia, he was proceeding towards a Zavanelli. Within 60 seconds he had tried multiple different maneuvers. In theory, you would want to retry those maneuvers, of course, before moving towards Zavinelli, but if you have the mindset of you're going to have to wind up doing Zavinelli, you would hope that you're doing it within a couple of minutes before things turn really bad.
Speaker 3:Right, yeah, but in the new show, the way they calmly establish rapport and get consent for time, you can tell it's 25 years or whatever later and the themes they're trying to emphasize are there. But the context that they've put them in of making sure that everybody understands everything and we've identified everybody in the room and all these things that maybe weren't prevalent in medicine in a more paternalistic model 25 years ago, they maybe aren't just appropriate for an emergency like this. So it feels a little weird. But yes, the timeline on the ER was way better and more realistic. But OK, so you're the resident here and that means I get to ask you questions.
Speaker 2:Hold up. I thought I was the one getting to ask the questions.
Speaker 3:Oh, ok, well, you'll get your turn. That's the premise of this, but first, for this ER pit discussion, walk me through the order of steps that you would use for shoulder dystocia.
Speaker 2:Oh, geez, okay. Well, let's preface this with I'm an intern, so it's usually not I'll correct you, don't worry?
Speaker 2:Okay, I have no doubt. Well, first, the first thing you should be doing is you're letting everybody know what's going on, so you're getting the relevant help. You're including neonatal support. You're getting your senior colleague in the room Nothing we love more than calling our chief in if they're not there already and then maybe anesthesia, so you tell the nurse to note the time that you're starting, because it's really easy to lose track of time during an emergency, and that's important. First thing, once you identify the dystocia, is you tell mom to stop pushing, because it's not a maternal effort problem, it's an anatomic problem with the baby's shoulder getting stuck under the pubic bone and so it needs to be released from that spot. And if she pushes, she's going to keep pushing it into a further wedge into that spot. And then what we don't do is give fundal pressure, which Carter tried to do in that ER episode, but he got yelled at for.
Speaker 3:Right, yeah, and you can tell they're emphasizing different little themes like that. And back then that was good. I mean, I appreciated that 25 years ago, right, and the maneuvers that are used with the shoulders are best accomplished, as you said, without her pushing. You actually are fighting against her if she's pushing. So you need to consciously tell the mother not to push while you're doing them, but instinctively, the staff, their heart rates up, everybody's a bit of a panic and they're sometimes yelling at the mother to push harder, as if this, again, like you said, is a maternal effort problem. But she needs to stop pushing, at least until you've dislodged the shoulder and you've rectified things. The other thing you need to do when you note this dystocia is have the patient lay flat on her back, as flat as you can, which again, was totally off in the pit.
Speaker 2:It was certainly not setting straight up in that high lithotomy position, the way she was in the show. Yeah, and I already alluded to how much I loved that part of it. So next you call the nurses to do McRoberts maneuver and then that's followed by a suprapubic pressure and you want to direct that pressure at a right angle towards the posterior aspect of the anterior shoulder, not with the palm of your hand like they do on the show, and so that way it makes it easier for the physician to do the internal Rubin maneuver at the same time, and then hopefully you can get it relieved with that. You need to make sure that you're using in clear words what you want from the nurses and what direction you want them to push. That's very important. Call out their name or point to them or honestly even guide their hand to where you want it to go. If time is of the essence, and then certainly if those first line things aren't working today, we would just go straight to delivery of the posterior arm.
Speaker 3:Right, and that hasn't always been the case. I appreciated that too, because the algorithm that would have been present for the ER in the 90s is definitely different than today. Today we are emphasizing if McRoberts doesn't work, superpubic doesn't work. No-transcript.
Speaker 2:Yeah, and then you might try the wood screw. You don't need an episiotomy, unless you need one to get your hand in to do delivery of the posterior arm or something like that. And then of course, you can repeat all those things with a little bit more force if things still aren't working before you consider this Avenelli maneuver. And of course, time is of the essence and you really want to be through all of these things in a couple of minutes, if it's possible.
Speaker 3:Okay, yeah, all right. Well, walk me through hemorrhage then.
Speaker 2:Hemorrhage yes, if there's one thing you get good at in turn year. So once again you've identified hemorrhage, and so the first, most important thing is activating your team and getting ready at least to insert additional IVs. You're getting the people you need to support you to run and get medicines, blood things like that. But while you're doing all that, most postpartum hemorrhages are going to resolve with just real bimanual massage, not the one you saw in the TV show. So the oxytocin should already be running. After that anterior shoulder is delivered, you should already have the pit, or you should be telling the nurse to have the pit running. That's the best thing to prevent postpartum hemorrhage, and so they might have prevented that had they started it earlier in that pit episode. And then people disagree, I think, about the order that you give uterotonics. But most people have moved away from giving mesoprostol as the first thing that you're going to do, because it's not going to act as quickly. So we're moving towards methargin or hemibate, and obviously you want to know about their comorbidities if you're giving those medications and then you can decide on the mesoprostol later.
Speaker 2:I know it's still unclear as well how helpful TXA is, and it's been a fad to give it early on, but it doesn't stop bleeding, and that's important to know. I do think people are thinking about it as something that helps the bleeding stop, but that's not what it's actually used for. If all of those things aren't working, of course we've checked for cervical and vaginal lacerations. We've ultrasounded the uterus to look for retained products or a blood clot. You can obviously do a bimanual and also put your hand inside that lower uterine segment to make sure that you're clearing out any clot and that there's nothing sitting there allowing them to continue to bleed. And then you can start thinking about the Bakri balloon or the Jada, and they both have equal efficacy that we know from our studies. So the Bakri balloon is a more financially responsible choice.
Speaker 3:Yeah, good, yeah, so you got this. Txa doesn't stop bleeding but it may prevent a concept of coagulopathy. So if you get into massive hemorrhage, we're using up all these products. Txa may help you down the line. But yeah, I do think people talk about it and actually in a couple of episodes later of the pit during their mass casualty stuff, there's a comment made about giving TXA as if it's going to stop bleeding on a traumatic wound and so it doesn't stop bleeding but it may prevent the DIC that results from a consomptive coagulopathy, or make that less likely.
Speaker 3:But, as you said, the studies aren't showing the kind of improvement that I think people think it might benefit most people. So, okay, well, back in this podcast, episodes 4, 13, and 5, 1, those were the ones that Antonia and I did on obstetric emergencies. So residents in particular can go back and listen to those for more details about these and other emergencies. But it feels like they again, they knew the ingredients of these emergencies but they didn't quite know how to put them together in a way that at least looks sensible to OBGYNs. But I also think a lot of doctors do that with a lot of different things, and residents certainly do it. You read the theory of something, or you read the protocol or the algorithm, but then it's not matched up yet with experience about how to actually bake the cake. So that's why you need attendings who have the experience. Does that sound condescending, even if you've read the book?
Speaker 2:Oh, it sounds just like yeah.
Speaker 3:Just a little, yeah, okay.
Speaker 2:No, that's okay.
Speaker 3:Hey, you know, it's four years.
Speaker 2:Yeah, four years, yeah, so okay. Well, we've talked about all those things, so do I get to ask some questions now, since you've decided to pimp me?
Speaker 3:Oh, I would not call that pimping. I mean, I can ask those kinds of questions if you want. But I don't have time on the podcast, so go ahead and ask me some.
Speaker 2:Okay, please, all right. Well, let's talk some common labor triage approaches. So this is bread and butter for new OBGYN residents that are coming in. Every program has different expectations, different approaches to the diagnosis of well labor, and rupture of membranes is the most common one, so especially preterm labor, so we can talk about that a little bit.
Speaker 3:Of course.
Speaker 2:Okay, so let's start with term labor. So the patient comes to the hospital for a labor check because she's having some pain or contractions, so how would you manage that?
Speaker 3:All right, start with the basics. So the diagnosis of labor of course is just regular uterine contractions plus cervical change. So we monitor for contractions and we evaluate the cervix. If the cervix is dilated or soft or thin, then some period of evaluation over an hour or two might be necessary. Then you're looking for progression and change.
Speaker 3:If she's not really contracting or she's contracting in an infrequent or irregular pattern and the cervix is closed well in those cases, you often don't even need to keep them for a period of time to do a second check.
Speaker 2:Okay, that seems pretty easy and standard, so does she need a non-stress test?
Speaker 3:All right, yeah, now we're getting into some places where we might spend extra time and money on a labor evaluation, so we'll put a link in the show notes to some cases in high value care from ACOG website and they actually have this one on what we're talking about the evaluation of labor at term and they give two scenarios. The first is the patient comes to clinic and complains of some contractions every five minutes and she's checked and found to be a centimeter dilated, but that's what she was at her previous visit. So you already know that she's been that and they do heart tones with a Doppler and she's counseled and sent home. In the second scenario she comes to labor and delivery with the exact same complaint but they keep her for two hours and they recheck her in that interval even though they knew that she was unchanged from her visit prior, and they put her on the monitor and of course they do a non-stress test and charge her for a non-stress test. Now in this ACOG document they say in that first scenario they assumed that there was a level three physician visit charged, although in truth that's probably for most practice situations just going to be included in the global fee just a part of one of the visits, and so they estimated the office-based appointment would cost $140.
Speaker 3:Again, in reality, in my practice setting, it would cost $0. It'd be no extra cost, it's just part of the global fee. Again, in reality, in my practice setting, it would cost $0. It would be no extra cost, it's just part of the global fee. But in the second scenario, where the patient goes to the hospital, the charge was $700 for the hospital visit and then for fetal heart rate monitoring it was $386. And then for the physician interpretation of the non-stress test, that was $161, plus the same level 3 visit. And oftentimes this is the case in the hospital because you have a laborist or a coverage group doing it. It's not part of the global fee. And then the hospital also did a urinalysis which was charged at $78. And this happens doesn't happen in my hospital, but you know people pull urines on everybody and so the total cost of the hospital-based triage was $1,474, for what was $0 in the clinic if it was in the global fee.
Speaker 2:Yeah, and you and I talk about this all the time. But I know that what's charged isn't actually what's collected or paid by the insurance company, but the scale is accurate. So it was 10 times more expensive to triage the patient in the hospital than it was in the clinic. So if the collected amounts are some fraction of what that's going to be, it's still going to be 10 times more in the hospital than the clinic. So I think that all the time when you send people to go be triaged in an ED somewhere or in the labor ED and it's just such a big expense.
Speaker 3:And we have some control over where these visits take place. I mean not at night necessarily, but if a patient were to call and is concerned about contractions while your office is open, then do you tell her. Is it your practice to tell her to come to the office and work her in and see her, or do you send her to the hospital? And how often are you telling patients when do the answering service calls, when you're answering those, or how often are you telling them to go to the hospital when they're concerned about labor, versus maybe talking to them about what's going on and having them wait a little bit? And when you counsel patients at prenatal visits about labor precautions, when are you telling them to go to the hospital versus the clinic, and for what symptom? How many contractions do they need before they should go to the hospital?
Speaker 2:Yeah, that's a very good question. I think I've heard everyone say a million different things. A lot of times we're taught to tell patients the 5-1-1 rule, which states that if you're having contractions every five minutes apart that last about a minute for one hour, then you should go to the hospital to be checked for labor.
Speaker 3:Right, and that rule might be appropriate for some women, for women who've already had multiple children, maybe for previous cesareans or people who are VBAC candidates things like that scarred uteruses but if you're telling first-time moms the 5-1-1 rule, then you're going to generate a lot of excessive triage visits, and so that's a starting point, and maybe a first-time mom should have something like the 4-1-2 rule. In other words, you're contracting every four minutes that are lasting a minute, and you've been doing that for a couple hours or some variation of that, customized to maybe where the patient lives, if she's already had what her obstetric history is, things like that, and this will help exclude some false labors. And then again, if it's daylight hours, why tell them to go to the hospital rather than the clinic, like whatever rule you're giving the patient for these precautions? If it's daylight hours, make your clinic available to them.
Speaker 2:Yeah, and it doesn't have to be a clinic visit. I have had patients many times come in contracting and they're contracting a little bit too close together for me to maybe send them home. They've had multiple babies before, or something like that, and so I'll truly tell them to just come back in an hour or two hours and I'll just quickly tell my nurse to put them in a room and I'll recheck them again super quickly.
Speaker 3:Yeah, go walk around for a bit. There's actually a walking trail around my office if the weather's good, or go do something for two or three hours and come back and we'll check you again.
Speaker 2:That's very fancy in your little community hospital. I can't say that there's a little walking trail around ours. Yeah. The other point they make in that value-based care module is that there's no indication for an NST, just as there would be no indication for a BPP. A patient who presents with a labor complaint doesn't have a reason to have an NST, and so it's inappropriate to charge for that, even if the patient's on the monitor. But I think you'd be hard pressed to find multiple hospitals or physicians out there. I think everybody just routinely does it out of habit. Okay, so what if she complained of leaking fluid?
Speaker 3:Okay, we're escalating a little bit the complexity of this, so they actually have on the same website another one of these value-based care modules or vignettes for term rupture of membranes. In this case both scenarios take place at the hospital, but of course the same point could be made. A patient could come to the office to be evaluated for rupture of membranes as well and not go to the hospital. But in scenario one the patient receives a speculum exam to look for pulling a fluid and she also receives a nitrazine test or a pH test and they make a slide and they see no arborization and she's sent home after a few minutes.
Speaker 3:In the second scenario, she receives an amnesia test and then she's sent home after it comes back in a few minutes. So the difference in these two examinations is basically the cost of the Amnesure, which they put at $513. The total charge for the second scenario is $1,336, including the hospital visit. But of course we could do this again in the office and it would be much cheaper in the office or maybe even in again the global fee if you're not doing the Amnesure test and you're not charging for an E&M visit. So the important part here is that the amnesia test, at least according to this module costs over $500.
Speaker 2:Well importantly, ACOG currently doesn't recommend that amnesia or some of the other tests, like Actim PROM, be used as the primary method of testing for rupture of membranes. The amnesia test identifies placental alpha microglobulin 1 in vaginal secretions and it has a sensitivity for rupture of membranes of about 99% in the original studies, although some newer studies have shown a sensitivity closer to 95%. But depending upon the pretest, probability of ruptured membranes for the patient, the false positive rate can still be as high as 30%.
Speaker 3:Okay, well, there's a lot of statistics that you just got into and this is actually like an important point. So we're talking about triage algorithms and these diagnostic algorithms. For anything, understanding how these statistics work and how these tests work is essential. So it's true, the amnesia is a better test individually than any of those individual tests that we traditionally use for ruptured membrane screening, including the speculum exam to look for pulling, or the pH test, or the nitrous, or what people call nitrosine test, or a slide to look for ferning or arborization. But depending upon the patient's pre-test probability, you don't necessarily need a better test. You also don't need all of those traditional tests the speculum, the nitrazine, et cetera. You don't need to use those every single time you're evaluating a patient. So each of those tests alone are not that great, but when they're added together they combine to make a test that has a very reasonable positive and negative predictive value.
Speaker 3:I think we're sold a lot of tests or a lot of testing algorithms or even pharmaceutical and other products, because we're told that this is the best for something, and that often is even true, but you don't always need the best. If I need to screen you for HIV, for example, I can use an inexpensive antibody test and then I can do a more extensive confirmatory test later, and understanding the statistics of how these things work helps you appreciate that you're trying to get a certain positive or negative predictive value.
Speaker 2:Okay, well, you're the king of statistics, so how about you explain the pretest probability affecting how these tests work?
Speaker 3:Statistic.
Speaker 3:So how about you explain the pre-test probability affecting how these tests work, King, I don't know if I'd go that far, but well, let me give vignettes from my book Clinical Reasoning, which is about all this stuff, and in there we talk about premature rupture membranes as the example to explain some of these concepts in one of the chapters.
Speaker 3:And so understanding how the patient's pre-test probability when you take their history, interacts with the performance of the test, the sensitivity and the specificity of the test, will be important for understanding this but also other labor evaluation tools that we might use, or if we talk about diagnosing UTIs or anything else. So we're trying to understand, ultimately, the positive and or negative predictive value of a test. And if you look at the formula for positive and negative predictive value, it utilizes the sensitivity and specificity of the test you're using, but it also has the pretest probability. So when you take a history and you listen to the patient's complaint, you have to have some sense of the pretest probability that she actually has, in this case ruptured membranes. So imagine that patient number one presents and she's 22 weeks gestation and she comes in after she noted a small, three centimeter wet spot in her underwear after she got home from exercising and there's been no subsequent leakage. She's had no contractions, she's had no bleeding. She's had no cramping.
Speaker 3:And she has a history of two healthy pregnancies with two healthy term deliveries. Now patient number two comes in. She's at 41 weeks gestation and she reports a large gush of fluid. While shopping for pickles she's got fluid running down into her shoes. She reports continued leakage and she's contracting every three minutes painfully. And she also reports that some of this fluid is green in color, looks very much like meconium, and you check her and she's eight centimeters dilated. So what do you think about the pretest probabilities of these two patients?
Speaker 2:Okay. Well, I think you're making that very easy for me. So patient number one's pretest probability is obviously very low. Let's say ballpark 5% or less. And then patient two's pretest probability is very high. I would say 95% or higher.
Speaker 3:Right, yeah, and the exact numbers don't really matter. I think that trying to focus on the exact numbers is where people get lost in some of this. They don't really matter. Just recognize that the first patient has a very low pre-test probability. When you talk to her, you don't think she's ruptured, you think she had sweat or something right or she peed on herself. And then the second one is I'd say it's even higher than 95%, but it doesn't matter.
Speaker 3:Everybody has an instinct that this woman's water's ruptured and it doesn't matter if we know for sure that it is or isn't right. We could have another vignette where the patient has an intermediate or indeterminate pretest probability, and you can imagine those scenarios for yourself. You're not quite sure you talk to her and you're like well, maybe, but you're not quite sure you talk to her and you're like well, maybe, but you're not quite sure. The exact numbers don't matter that much. But now let's talk about the performance of the tests that we're using. So the nitrazine test or a pH test has a sensitivity of about 93% this will be different studies, but the exact number doesn't matter and it has a specificity for rupture membranes of about 83% and the sensitivity of a Ferning test for a patient who's in labor is 98%, but, importantly, it's only 51% if they're not in labor. So, like in the first vignette, the sensitivity is only 51% and the second vignette 98%, and then the specificity also varies. So it'll be 88% if they're in labor but only 70% if they're not in labor.
Speaker 3:So the positive and negative predictive values of these tests are going to be different for the two patient scenarios I described. In fact, the positive predictive value for a nitrosine test in the first patient is only 22%, meaning if the test is positive, the chance that she in real life is actually ruptured is only 22%. But in the second patient the positive predictive value is 99%. The same test, done the same way by the same person, has different meanings for these two different scenarios because they have different pre-test probabilities. And then the negative predictive value.
Speaker 3:So if the test comes back negative, the chance that she's not ruptured. Well, in the first patient it's 99.6%. The girl that worked out is 22 weeks. If the nitrazine is negative, the chance that she's not ruptured is 99.6%, but it's only 38.4% in the second patient. And your common sense would tell you not to trust that negative test in the second patient. So the truth is, given the low pretest probability of the first patient, a simple nitrazine test has such a high negative predictive value. That's probably the only test that you even need to do, and you might only harm the patient by doing more tests and running the risk of finding a test that has a false positive, whereas in the second patient, a nitrazine is also the only test that she likely needs because it's more than likely going to be positive, and doing more tests would only run the risk of having a false negative.
Speaker 2:So a nitrazine test is sufficient for both if you understand what the results mean. And the truth is not doing. Any tests might be appropriate for both patients as well, depending upon your pre-test probability. So then you would order more tests only if the nitrazine were either equivocal or not consistent with what you expected to find. I will say.
Speaker 2:One extra question that I'm adding on is essentially I think a lot of times you'll have patients come in and they'll have ruptured somewhere, and then they're a transfer in, and so someone else did their initial exam. They might've seen something. They get to you you get absolutely negative testing, but someone else was already calling them ruptured. You do your pooling, nitrazine ferning, everything comes back negative, but her story's suspicious. Someone else somewhere saw something, and so what are you supposed to do then?
Speaker 3:Yeah, and this is where some of the other testing that you might do comes into play in the scenario you described is actually quite common and this is actually the harm of these tests being done. Somebody takes as a patient who's not in labor, she's 28 weeks and she has a positive ferning. Well, remember, the performance of ferning test for a patient not in labor is actually quite low but we all think of it as like the gold standard, almost like what else would cause ferning. Well, the fingerprint does. A fingerprint on the slide does. Like most of these ferning tests in a patient not in labor shouldn't be trusted. But they transfer the patient. She's got PPROM, all this stuff, and now you've got her.
Speaker 3:And so if you have equivocal results or you're in a scenario where you have conflicting information, well, that's where some of these other tests, like an Amishure, might be valuable and might be used. It should be rarely used given how extensive it is. But now you're talking about a patient who faces a prolonged hospitalization, maybe even early delivery at 34 weeks over a false diagnosis. A lot of transferred PPR, 34 weeks over a false diagnosis A lot of transferred PPROMs are a false diagnosis. You might even do a SMRF test for a patient like you described, or just serial exams Repeat, finish your steroids, start on the antibiotics, assume the worst, but if you're finding no evidence of it with subsequent testing, it's okay to say hey, we had a false positive test result.
Speaker 3:This is also the importance of understanding how easy it is to make a false diagnosis of rupture membranes if you have too much confidence in these tests. Even the amnesia test remember the amnesia test would still run as high as a 30% false positive rate in a patient with low pretest probability. So in some patients you might smurf them before you actually deliver them, and that's a slang term for injecting dye by amniocentesis needle into the amniotic fluid. Put a tampon in the patient and if it doesn't turn blue she's not ruptured. And people call it a smurf test because if you happen to deliver the baby shortly after doing that, it'll have a bluish appearance.
Speaker 2:Don't let Nikki freak out. Yeah, so the same reasoning would be true for the Actin-PROM test. Then this test detects the presence of insulin growth factor binding protein 1, which is a protein present in amniotic fluid. It's about 97% sensitive, which is basically the same sensitivity that nitrazine has, but it's more specific than nitrazine alone. The way I think of this is the tests are equally sensitive, and when I'm trying to rule out rupture membranes, the sensitivity is what matters. As long as the nitrazine is negative, then it's just as good as having a negative actin PROM or amnesia, but if it's positive, that's where the specificity is going to be important.
Speaker 3:Right. But just in like in that second patient, she was obviously ruptured because her pre-test probability was so high that nitrazine is still adequate, even though it has a lower specificity. So the point is you have to be thoughtful about what your pre-test probability is for different patients and then understand how and what, how these different test performances interact and which test is appropriate. The gold standard, the point we just made. The gold standard may be the dye infusion test, the Smurf test. That may be the gold standard, but does it make sense to do that test on every single patient who comes in? And they had two mLs of fluid in their underwear? Of course not, and so people know that what I'm saying is true. But they're maybe less reluctant to do that one because it's an invasive test. But they're reluctant should be because it's just not a necessary test in most patients. And the same for these tests.
Speaker 3:It's not that the Actinprom test or the Amnesure are bad tests, and if the Amnesure test was like $3, hey, let's do it on everybody, that's fine. It's not that it's a bad test. It's that it's expensive and it's unwarranted in most patients and it may provide bad information if you're over utilizing even that test. Again, if you're using this in patients with the most minimal complaints and you're getting positive results 30% or so of those positives may be a false positive Then you get that patient transferred to you. She's on antibiotics, she's on steroids. She sits in the hospital for four or five weeks and gets induced at 34 weeks and her water was never even ruptured.
Speaker 2:Yeah, okay, well, you brought up the pretermers, so let's talk a little bit more about that. So I want to talk about fetal fibronectin and cervical lengths.
Speaker 3:Yeah, well, for fetal fibronectin, and Tony and I talked about this a lot back in episode 8.1.
Speaker 3:I think that's the one where we talked about important articles in OB and we talked about the original study by Charles Lockwood in 1991 that found that the presence of fetal fibronectin above a certain threshold resulting in a positive test had an 82% sensitivity and specificity for preterm delivery in a population of symptomatic patients. But the test was later marketed for its negative predictive value because those aren't actually that great in numbers, for its negative predictive value because those aren't actually that great in numbers. And then it became a test for triaging for preterm labor in particular. So this gets back to what we just talked about pretest probability. The same stuff's going to apply. So we discussed this in more detail in that episode and we talked about some high and low pretest probability scenarios and essentially the test ends up being useless in most clinical scenarios because you've got a lot of clinical information about the diagnosis of labor from the contractions and from the cervical examination and so go back and listen to that episode for more of the specifics of that study. But it's essentially a useless test.
Speaker 2:Yes, I agree. So basically, if a patient clinically isn't changing their cervix and doesn't have a regular contraction pattern, then a negative test does give you a high negative predictive value, but also the clinical scenario itself just tells you that there's a very low likelihood of it. So you all talk about a difference of 97 and 99% negative predictive value for a patient who's not showing clinical cervical change and that's maybe not worth the cost. But also a positive test doesn't mean much because there's lots of reasons why it's positive. And so if a patient who's not changing their cervix and isn't in a regular contraction pattern has a positive test, then what are you supposed to do with that? And conversely, a patient who is changing their cervix but has a negative fetal fibronectin is not somebody that you're just going to send home.
Speaker 3:Right. And if you work through clinical scenarios like that and just ask the question, how would it change my management? It doesn't really. But people have looked for ways of making some meaning out of a positive test in a patient who's maybe not in labor. Like, maybe this is predicting something and do we have an opportunity to intervene? Are we finding the patient who's going to really be in labor clinically in a week or two?
Speaker 3:So people have done things like add antibiotics or even use that as justification to give steroids for the fetal lung maturity or something. Maybe they observed them longer because they had a positive test, but the test doesn't have meaningful positive predictive value. That would warrant those sorts of things and also the interventions I just mentioned. They haven't been shown in clinical studies to make a difference in the outcome. I'm not talking about the steroids per se, but giving antibiotics or azithromycin or what are you going to do? Bed rest or whatever. Like we don't have an intervention right now adding permetrium or something like that. So as a reminder, acog practice bulletin 171 states that fetal fibronectin alone or in combination with cervical length measurements has not been shown to provide useful information for the clinical management of patients.
Speaker 2:Okay, so let's talk then for a minute about cervical lengths. So there's two types of cervical lengths of interest here. One is the idea of universally screening the cervix at the anatomy ultrasound between 18 and 24 weeks, with treatment of patients with a cervix less than or equal to 25 millimeters with daily progesterone or a pessary or a vaginal progesterone cream. And then the other is using cervical lengths for patients later in pregnancy who are presenting with symptoms of preterm labor, to help determine if they are in preterm labor.
Speaker 3:Right, so let's take the first one first, and most of us have gone to a program of universal cervical link screening of low-risk patients meaning patients without a history of preterm labor, things like that risk factors to find those patients who have that shortened cervix that you mentioned, especially after there was a trial done several years ago that found that treatment with crinone progesterone cream was effective at reducing neonatal morbidity and mortality. The PREGNANT study is what it was called. It was published in 2011 by Hassan and Romero and they gave women with in that study women who had a 10 to 20 millimeter cervix, measured between 19 and 24 weeks. They gave them a daily dose of 90 milligrams of 8% progesterone cream that's what crinone is and they showed a lower risk of respiratory distress syndrome, a very low birth weight infants and overall neonatal morbidity and mortality. So that was the sort of like oh, we have an intervention, there's something we can actually do, so now let's find the patients and give it to them.
Speaker 3:A study in 2007, so before that by Fonseca and colleagues had randomized women with a cervix shorter than 15 millimeters, discovered between 20 and 25 weeks, to 200 milligrams of vaginal progesterone or prometrium versus placebo, and they did find slightly fewer bursts before 34 weeks, but it wasn't associated with any improvements in neonatal morbidity or mortality, meaning that most of the changes in the time to delivery they were at a window of time where it didn't have any impact on neonatal outcomes. But from these studies and a few others like that, the idea of universal screening for a shortened cervix came in to being and was implemented by most of us. But then people questioned does the type of progesterone matter? Can you use permetrium instead of crinone, for example? Or should we be doing a pessary instead of these or in addition to these things? Or should we be managing these patients with a cerclage, with or without some type of progesterone? So lots of variation came out of that. Afterwards.
Speaker 2:Yeah, and you see all of those different things being done and you also see different cutoffs for intervention. Some people use less than 15 millimeters, or some less than 20, some people even 25. And so there's lots of different questions in there. You'd think if something was going to work it would work best in the shorter group, but maybe the shorter group is too short and maybe an intervention like progesterone works better in the slightly longer group.
Speaker 3:Yeah, lots of questions and lots of theories and lots of variation in practice and lots of studies have been done over the years. And also there's a question of is this the same in twin pregnancies versus singletons, and that may be a really good question. Actually, not all studies that have been done have a placebo group either. So there was a study in 2025, just published in February of this year that looked at cerclage versus pessary with and without vaginal progesterone in twin pregnancies. That seems to favor cerclage in twins and this is in keeping with some other recent trials that have said that cerclage might be the way to go for twins, but maybe not singletons. So let's focus on singletons for a minute. A study actually out this month in the gray journal, mfm the pink journal, I guess we can call it looked at cerclage in singletons with a shortened cervix less than 25 millimeters before 24 weeks, and they found that adding a cerclage to progesterone alone seemed to make no difference in outcomes, though they might have stayed pregnant a little while longer. But again, outcomes weren't any better, and that's always an important thing to clarify. Like for tocolytics, for progesterone, for cerclages, for anything, the goal is not to keep a patient pregnant for some longer period of time. The goal is to improve neonatal morbidity and mortality. So a trial has failed if it doesn't show an improvement in neonatal morbidity and mortality. And I think it took people a long time to understand this. It's just assumed that if the pregnancy is prolonged that's a good thing. But that has to be proven, and so think about why it might not be a good thing. Let's say, a patient's in preterm labor or whatever PPROM anything because of an underlying inflammatory cascade set apart by some infectious process. So maybe you do have a mechanism mechanical like a cerclage, or a drug like a tocolytic or something like that, that will prolong that pregnancy for three or four or five or six more days. But in the meantime the subclinical infection becomes more manifest and the inflammatory pathways start affecting the fetus in ways that might encourage more necrotizing enterocolitis or more brain matrix instability and more interventricular hemorrhage or periventricular leukomalacia or something like that. So the question is, if you think about it this way, if you even had an intervention that you knew for sure would keep a pregnant, keep a woman pregnant, say, five days longer than placebo would, but now you've got, let's say, a 24 week and five day pregnancy. That there's a lot of infection or inflammation in some of these critical pathways, versus 24 weeks, and there's no sepsis, no infection and less inflammation in these pathways. Which baby would you rather have? And so you have to actually prove that it's beneficial. You may actually be harming these pregnancies by keeping them pregnant longer, so we focus too long on the time to delivery rather than neonatal outcomes, and so that's why don't be distracted by papers that say they stayed pregnant a day or two longer when there was no improvement in neonatal outcomes.
Speaker 3:A study published last year in the same pink journal looked at the strategy of introducing universal screening in Italy.
Speaker 3:So this is one of those real life strategy papers.
Speaker 3:Let's implement it and see what happens.
Speaker 3:And they had treatment for all the cervical links that were less than 25 millimeters, and their treatment included 200 milligrams of progesterone daily, along with a pessary, but they had an arm that included women not getting screened, so they got no treatment, and they found no difference at all in the time to delivery, and this is curious. I think, though, what it does is it adds to the evidence that prometrium, that 200 milligrams of progesterone, is probably not effective. That's what the older Fonseca study really showed, especially when you think of it in terms of neonatal morbidity and mortality, not time to delivery, and obviously pessary is probably not effective. And so I think that study adds to the evidence that if you are doing this and you're doing treatment, it's probably the progesterone cream is what we're hanging our hats on for now, and also this adds to the evidence that is consistent. I think that pessary and cerclage, at least for singleton pregnancies, not twins, is likely not helpful and might even be harmful, because cerclage increases the risk of PROM just due to the foreign body and the surgery itself.
Speaker 2:Okay, so helpful in twins maybe, but not necessarily singletons.
Speaker 3:Yeah, I think that's where we're at right now and I mean, I think there's a lot of gray in all of this, but again, people's practice should be informed by the trials that we have available, and right now I think that's where we're at Crinone for singletons, maybe crinone and pessary for twins, or you might abstract multiples to that too. There's also perhaps the question of which, as you mentioned, which cervical length cutoff should we use, and most of the newer interventional trials have gone up to 25 millimeters or less. So there's still always this question, too, of what's the optimal cervical length, and I do think it's interesting. Maybe patients with very short cervixes, as you said, don't benefit. There's a study in the British Medical Journal in 2023 that clearly shows that past three centimeters were not benefiting patients going that far. But in between, like 15 and 25 millimeters, things like that, you're going to have different types of studies and probably room for more research in there to figure out what the optimal length is.
Speaker 3:I wouldn't criticize people for especially with their progesterone cream for treating people under 25 less as opposed to 20 millimeters, something like that because it is a fairly inexpensive and non-invasive intervention, and so I think that's where we're at Crinone cream, progesterone cream for, let's say, under 25 millimeters but up to three beyond. That's not effective. And then, as you said, cerclage for twins plus the crinone cream is probably where we're at with this.
Speaker 2:Okay, so what about using cervical length as a triage tool for threatened preterm labor?
Speaker 3:Right, so this is the second use of it. So now we're later in pregnancy. Everything we've been talking about before was before 24 weeks, when you're measuring it as part of an anatomic ultrasound, and this is much like fetal fibronectin. Of course, patients with shorter cervixes are more likely to be in preterm labor than patients with longer cervixes, but you'd still be hard-pressed to find a case where that knowledge changed a patient outcome or patient management compared to what you already know from your clinical exam or even your digital exam, because you're assessing how long the cervix is when you check them. If you check somebody and they were one and a half centimeters long and you'd be less worried about them being in preterm labor than if you check them and they're a half centimeter long or they're 90% effaced or something. So obviously we already know that a shorter cervix is going to be more associated with true labor than false labor. But we need to decide if doing an intervention like using an ultrasound to figure that out and doing that for everybody who presents with threatened preterm labor actually changes outcomes in a meaningful way or allows for some opportunity for intervention. There was a trial published back in 2007 that we'll put a link to that found that a combination of fetal fibronectin and cervical length measurements though these were done together where the cervical length was looking again, this is in later preterm patients for cervixes longer than 30 millimeters or less than 30 millimeters they found that the combination of this resulted in a reduction in the length of evaluation time for women with threatened preterm labor and in the incidence of spontaneous preterm birth for women in preterm labor. And these were subset analysis findings in a very small study with only 100 women total, randomized, and that has not been replicated. But this was the basis of what a lot of residency programs are doing today, where patients are being triaged who are present with symptoms of threatened preterm labor, with fibronectin and cervical length. So if the cervical length is less than 20 millimeters, then the patient will receive treatment at the physician's discretion. If it's between 20 and 29 millimeters and the fibronectin is positive, then they'll receive treatment at the patient's discretion. If the cervix is between 20 and 29 millimeters and the fibronectin is negative, then you can just continue to observe them for 24 hours and decide if they're stable or not. But if the cervical length is greater than 30 millimeters and their fibronectin is negative, then you just discharge them home. So that sort of algorithm that you see is based upon this study.
Speaker 3:Now they only had 51 patients in the arm that underwent management and these had different combinations of those results and they compared that to what they called standard management, where they still collected the fibronectin and the measurements but they were blinded to them. But the real problem with this study was it's just way too small to make any assumptions about the outcomes, and it also assumes that admitting patients and giving them a tocolytic this is back in 2007, when this was still a very common believed in practice that it would make a change. It would affect ultimately when they delivered, even though none of the patients delivered within 48 hours anyway, right, when they delivered, even though none of the patients delivered within 48 hours anyway, right? So no tocolytic study has ever shown that tocolytics ultimately affect the time in which patients deliver. So the study was way underpowered to answer any of those questions. It was just the number of patients treated were in the teens.
Speaker 3:They actually concluded that the fetal fibronectin didn't change anything. When they looked at it, they noticed that knowing the fetal fibronectin test result compared to the cervical length didn't change anything. It wouldn't have mattered and didn't make a difference. So I think that this study has had a huge impact on the way people have triaged preterm labor patients. The author is very influential in the obstetric MFM community. But a way bigger impact than it should have had. It should have just led to subsequent studies, and subsequent studies that have been done have shown that cervical lengths actually perform better than fetal fibronectin. I mean, really that study said that too, but it hasn't been shown that an ultrasound acquired cervical length is giving any better information than what you already knew from your digital exam.
Speaker 2:Yeah, and what I'll say is sometimes, if they're not dilated, you can't necessarily estimate the length of their cervix with a digital exam, because you can't get your finger through, although you can typically still tell if it's long or not.
Speaker 2:The other thing I think is interesting about these studies you're talking about is what symptoms the patients presented with and how they were allocated.
Speaker 2:In other words, do they all have contractions every two or three minutes and they're huffing and puffing and doing something, or are they mostly patients who come in with an occasional contraction that in another world we would just call it Braxton Hicks? Most of them don't define how much uterine activity was necessary to be enrolled in the trial and almost none of them show any differences in time of delivery at 48 hours, but instead they focus on who will deliver before 37 weeks or 34 weeks. And I think that's important because if the patient is going to imminently deliver and is in real labor, you're going to see that with just the clinical exam and the history. But there is a subset of patients who aren't going to imminently deliver, who will go on to deliver preterm because they have a shorter cervix than the next patient does. I think that's clear and maybe you benefit those patients by giving them beta-methazone, but you don't necessarily have to admit them to the hospital to do that.
Speaker 3:Yeah, and that's a great point too. If the primary benefit of finding these patients who are at increased risk via digital exam or shortened cervix by ultrasound or whatever, if the benefit is basically finding who should get beta methadone, well, you can do that as an outpatient. So I think that we've taken the ultrasound cervical links and we've substituted them for physical exam, and maybe that happens more often in residency programs because we don't trust the residents and we don't trust their exams. And maybe there's even validity in that I'm not harshing on that too much Maybe seeing what you're feeling with your hand and confirming that with ultrasound I mean, there's a world in which we do the whole digital exam with ultrasound. That's a thing. Right, you can see how dilated a person is with ultrasound and maybe somebody should do a study to see if that has value. But I'm not aware that study has ever been done or that anyone shown that sort of approach has a benefit to the patient.
Speaker 3:These studies don't control or create an algorithm for basing what you do with the patient on cervical exam and the knowledge you get from that versus ultrasound. Talking about dilation and talking about effacement are two different things and we're supposed to be getting both pieces of information from our digital exam. So imagine you had a study where patients who were, let's say, 80% effaced or something more they received a different treatment compared to patients who were, say, less than 30% effaced or some number. Because that's essentially what you're doing with the ultrasound. You're saying, if they're greater than three centimeters or longer, with the average cervix being about four centimeters in non-laboring patients, you can compare that to the same kind of study where you just do this based upon the information you gather from your exam. So that's what's needed to convince me that there's value in ultrasound. The same results found in these ultrasound studies could be done if you just substituted the effacement from your digital exam.
Speaker 2:Yeah, and I think just we've said it already but you should just always be asking the question every time of how any test or exam you're going to do is going to change your management.
Speaker 2:Do I need to digitally check and do a transvaginal ultrasound and expose the patient to two things that maybe aren't necessary? So if we're convinced that they're ruptured or not ruptured by history and a nitrazine alone, then we shouldn't do more tests because it doesn't change the management. And if they're obviously in preterm labor to the point of being admitted based upon exam and symptoms, then we probably don't need more tests. And if they're obviously not in preterm labor based upon exam and symptoms, then we certainly don't need more tests. And if we're using a screening test for less symptomatic patients, then it needs to be an intervention that's offered to them that has been proven to be effective. The ACOG Bulletin 171 that you mentioned says that no randomized controlled trials have confirmed the suggestion of benefit from observational trials for both fetal fibronectin and cervical length measurement, and I think that's important to say. We do a lot of things that haven't actually proven to give us any benefit or give our patients any benefit.
Speaker 3:Yeah, it's all.
Speaker 3:A lot of this is just in the theoretical world, but you know, for academic, for residents and academic programs, okay, do the study, then You've got this is exactly what people should be doing and fortunately we just make it standard of care without the evidence.
Speaker 3:On the podcast we've talked about, for example, how we do this with thromboprophylaxis for patients at high risk for DVT, and we've just adopted things based upon theory and made them standard of care, where the burden really, especially with an intervention that has potential harms, is to do the clinical trial and she'll benefit. And Tony and I are going to talk about trials in the next episode that are coming out again showing no, there's just not benefit from this. So we're running out of time. But another good sentence in that practice bulletin is this one, and I'll just quote it no evidence exists that tocolytic therapy has any direct favorable effect on neonatal outcomes or that any prolongation of pregnancy afforded by tocolytics actually translates into statistically significant neonatal benefit. And a reminder of putting that in context with what I said a minute ago about which outcome's important how many minutes somebody stays pregnant, or the neonatal outcomes.
Speaker 3:Then there's some real conversations again to be had about what we're doing with tocolytics. So I don't think people are practicing in line though with that practice bulletin 171. I think that's important because, again, most of the reason that people care about some way of identifying patients who should be admitted with threatened preterm labor is so that they can give tocolytics and steroids. And studies show that if you use cervical links you'll increase the proportion of patients who do get admitted and treat them, but you're not improving outcomes when you do that.
Speaker 2:Yeah, I can confidently say that some people are not following those guidelines, yeah, okay. Well, this has been fun. I want for one. We'll be very excited to hear Antonio's voice again back in a couple of weeks. It's time for me to go back to hiding behind my Instagram account.
Speaker 3:Yeah, well, you'll be back, because there's a lot of other common things like this that we've got business to talk about, so we'll have you back on in a little bit.
Speaker 2:Okay, sounds good.
Speaker 3:And we'll see you all in two weeks.
Speaker 1:Thanks for listening. Be sure to check out thinkingaboutobgyncom for more information and be sure to follow us on Instagram. We'll be back in two weeks.