Episode 147 - Your Ultrasound options in Pregnancy
Mel:
[0:00] Welcome to the Great Birth Rebellion podcast. I'm your host, Dr. Melanie Jackson. I'm a clinical and research midwife with my PhD, and each episode I cast a critical eye over current maternity care practice by grappling with research and historical knowledge to help you get the best out of your pregnancy, birth, and postpartum journey. Welcome everybody to today's episode of the Great Birth Rebellion podcast. I'm your host, Dr. Melanie Jackson and today we're talking about ultrasound options during pregnancy and I've invited a colleague of mine Phil Jones who's a sonographer and I first met Phil when he called me and said hey anytime you need anything for your clients just feel free to give me a call because Phil knew that they have very clear plans for their births have also very clear plans for their screening strategies. And so Phil was really accommodating. I've invited him on the podcast today to have a conversation around ultrasound options during pregnancy. Thanks for being here, Phil.
Phil:
[1:09] Glad to be here.
Mel:
[1:10] Can you start by introducing yourself to our audience? I know you, but everybody else doesn't. So what's your role, job? How did you get there?
Phil:
[1:19] So I am a stenographer, as you correctly introduced me as. I've been scanning in ultrasound now for around about 17 years. I did my training in a hospital and then moved on to scan mostly in private practice full-time and also working for an obstetrician gynecologist in the obstetric ultrasound sphere as well. Up until recently, I've always spent some time in dedicated obstetric ultrasound clinics. But since my role in general radiology has expanded, I've had to sort of move into general radiology full time. I still scan obstetrics within general radiology. It's not 100% of my work as it was when I was working for the obstetrician. It certainly still is a significant part of my daily work.
Mel:
[2:11] Are there sonographers who specialise and will only do obstetric ultrasounds?
Phil:
[2:17] Yeah. So typically, that's a mixture of obstetric and gynecology in that circumstance. So these practices are run and owned typically by obstetrician gynecologists, and they report on the scans themselves. And the sonographers that they employ, obstetrics and gynecology, is typically their specialty. Now, there are people like myself there that do some days in ONG clinics and also work out in general radiology. But there are also others who that's their full-time work. They only do obstetrics and gynecology.
Mel:
[2:46] So do you mean to say with those clinics that the sonographer will do the scan and then the obstetrician writes the report?
Phil:
[2:54] That's correct, yes. Yes, in that circumstance, yes. Whereas in a radiology clinic, the sonographer does the scan and a radiologist writes the report. The reports in theory should be very similar. However, you can imagine that obstetrician and gynecologists have a different level of experience in that field than a radiologist.
Mel:
[3:12] So do you think a report written by an obstetrician would be more or less accurate than one written by a sonographer?
Phil:
[3:22] I mean, that's a tricky, that's a tricky one. Accuracy comes down to a few things. So first of all, the sonographer. So the person with the probe in the hand, like me, I have to find the problem. So I have to be well-trained, I have to be thorough, I have to think about things very carefully so that I give the person who's writing the report as much information as possible and as accurately as possible as well. So that's the first step. So in terms of getting an accurate diagnosis or report, people like myself is the first step to getting that, making sure that the person that does the scan has the capability of providing accurate information. So the radiologist or the obstetrician will have all the images, all the measurements there, and then they can... Collate a report based on that information and yeah as long as it's given to them accurately although the recommendations from a from a radiologist and an obstetrician are often different so a radiologist will often now this is just generalizing because there are some really good obstetric radiologists as well but in general an obstetrician gynecologist reporter will have a bit more confidence to put recommendations in whereas a radiologist will typically just give the information. Right.
Mel:
[4:37] Okay. That's interesting because I knew that there were radiology clinics that you could go to and you'd get a report. And I knew that there were more specialty clinics. But I didn't realize the distinction between the sonographer not doing the report at those specialty clinics more likely to be done by the obstetrician.
Phil:
[4:58] Yeah. So the sonographer always, it's a bit of a tricky, So, legally, a sonographer never does a report. We do a preliminary diagnosis, I suppose you could say, on our worksheets. So, we will provide the reporting radiologist or obstetrician with all the imaging that they require and a preliminary worksheet with our list of things that were found. And then it's up to the radiologist or obstetrician to be able to look at that information and provide a report.
Mel:
[5:31] Okay. I'm going to jump into the questions because what I want to do today, and we'll revisit some of these finer details as we go.
Mel:
[5:39] I was hoping today we can chronologically look at all of the ultrasound options that are available to women from the beginning of their pregnancy all the way to the end, whether or not their clinician has found an issue with their pregnancy or if it's a routine one. So for those listening at home, this is going to be a bit of a catalogue menu of all the possible ultrasound options that you have available to you. And we're going to go through each detailed scan, find out what they're looking for, why they do it and then maybe that will help you with information about which ones you think you really, really want and need and which ones you might not want to have depending on your preferences. So let's start with the dating scan because that's scan number one. For some women who have had IVF, for example, may have a different experience but certainly when you get pregnant, and you wee on the stick and you head off to your GP or if you've hired a private midwife, then the first thing they're going to offer you is some blood tests, antenatal blood tests, and give you a referral for a dating scan. Phil, can you explain to us why do we have that dating scan? What does it tell us?
Phil:
[6:58] There's lots of things that the scan can see. Let's start with why the majority of people show up. The majority of people show up for their dating scan because their healthcare professional has sent them for that scan. That's the reason. Why they've sent them for that is lots of different reasons. We can accurately date the pregnancy by measuring how big the fetal pole is at that sort of early stage. And through research and data, they've figured out that the way that that measures, so how many millimetres the fetal pole measures, is a way of indicating how far along the pregnancy is so they can give you an accurate due date.
Phil:
[7:37] The other purpose of the scan is to confirm viability so we can see a baby's heartbeat. Now, what we can see depends on how far along the pregnancy is. So we don't see anything typically from four to five weeks of gestation. So between five and six weeks, we would see a gestational sac and that's about it. And then from six to seven weeks, we see a sac, a baby, a heartbeat. And so we can confirm viability. We can date the pregnancy. We can look for any, we can see how many gestations there are. So, confirm that it's a singleton or multiple. We look at the gynecology. So, we check the ovaries, make sure they're looking okay. We will look for any bleeding around the gestational sac. There's lots of things that we can look at. But then the main reason people come is they want to check everything's okay, right? That's the main reason why anyone comes for a dating ultrasound is that they want to know that everything's good. And so, we can see that there's a baby with a heartbeat.
Mel:
[8:32] And when you say the fetal pole, is that the measurement of the head to the bum? Yes.
Phil:
[8:38] Yes, it is. Crown to rump, so head to bum. And between, say, six to seven weeks, it's just like a grain of rice. So you can't really see much of a head or a bum. You can because you can see the early brain structures in a baby these days. So I know which one's the head or the bum, but it literally looks like a grain of rice. It's very small. And then as the pregnancy progresses takes to about eight weeks, then it starts to look a bit like a jelly bean. And so you can see put more of a crown and a rump in that circumstance.
Mel:
[9:05] So what I'm hearing is then, and this has happened to me before, is women get super excited and they head off for their dating scan the minute they know they're pregnant. And then they get told, come back in a week or two because we can't really see anything. So would you say that the optimum time for a dating scan is between that six to eight-week window.
Phil:
[9:29] Yeah, yeah. If there's no concerning symptom, then I would wait until about that eight-week mark. Early on in the pregnancy, we can look for things like ectopic pregnancy as well. And sometimes you pick them up incidentally. So people come around that six-week mark with no symptoms and we can see no gestational sac within the uterus and determine that the gestational sac is outside or there's concern of an ectopic pregnancy. But if there's no symptoms, typically if the patient can wait around the early eight-week mark for a dating scan, it just means that we can see things pretty clearly. Typically, not always, but typically you can avoid having an internal scan around eight weeks as well because the majority of the fetal anatomy is easier to see through the abdomen around the eight-week mark. So, yeah, if there's no concerning symptom like bleeding or a lot of pain and the patient is prepared to wait till eight weeks, then that's often the best time to come.
Mel:
[10:25] And are you saying that prior to the eight weeks with the routine way that the scan is done is that vaginally.
Phil:
[10:34] Depends so transvaginal ultrasound is a tool that we use only when it's necessary so i wouldn't routinely do a transvaginal scan on any patient it's only if i can't get enough information to get a diagnosis or to exclude any concerning diagnosis so up to seven weeks if the patient comes in and their uterus is say retroverted which is sort of flexed backwards sometimes a trans and abdominal scan is very difficult to see the anatomy that you want to get and to take the pregnancy accurately so then you would have to do an internal scan we don't have to you don't have to do anything honestly we have to get consent in that circumstance but we would recommend an internal ultrasound to get a bit more information to be able to sort of complete the scan properly and then we would also do a trans vaginal scan in the circumstance where we can't see the fetal pole or gestational sac anywhere because then we have to go looking very carefully for an ectopic pregnancy.
Mel:
[11:28] But generally when women are coming, they can expect to have an abdominal ultrasound.
Phil:
[11:33] Typically, yeah. And more so if you're over eight weeks. But you've got less than eight weeks, you've got a few things that may count against trying to get that diagnosis and that accurate dating transabdominally because you've got a lot of variables. So it's a whole bunch of things that can influence our ability to be able to see.
Mel:
[11:52] And when you do the measurement, that little crown to rump measurement, How accurate is it? I know that you put a line when you see them doing the ultrasound and they click from here to here, and then it makes a little line on the screen. Is there some kind of AI or calculation that happens in a computer program, or is that completely reliant upon the sonographer?
Phil:
[12:16] Yeah, so it's reliant upon the sonographer to determine the actual crown and rump of the phenol pole, yes. So, there are some things within the gestational sac which can be inaccurately determined as being the crown rump length, like with the yolk sac. So, there's a little sac that's near the baby that just helps to sustain the baby for the first few months of life called the yolk sac. And that can sometimes be mistakenly added to the fetal pole and you might get a baby that seems to be a bit bigger than it actually is. But it is up to us to determine what is the fetal pole. And once that measurement has been done, then the ultrasound system will calculate the gestational age based on that measurement. And that's just a bunch of data that they've created that puts the fetal measurement to gestational age through many research papers.
Mel:
[13:09] Sure. So somebody's gone through hopefully collated research about how big a baby usually is at that age.
Phil:
[13:17] That's correct.
Mel:
[13:18] And correlates that with millimetres, I assume.
Phil:
[13:21] That's right. And so typically it's more accurate earlier on in the pregnancy because once the baby gets big enough to flex and move, then that crown to rump measurement is not as accurate. So you can have a baby that's, say, 12 weeks, for example, and they can, like, be curled up and that's sort of, you do a crown to rump or you do a little bit of your straight out and that's sort of, yeah, it's the same baby, but you've got two different measurements, crown to rump, if they're stretching or flexing. So the earlier one, about 9, 10 even, they don't sort of typically flex too much, is more accurate than above then.
Mel:
[13:53] And in terms of accuracy, do they tell you at sonographer school, do they give you an idea of how... Accurate that actually is? What's the margin of error on a due date calculation based on a measurement?
Phil:
[14:10] When you're doing the measurements, you realise that it only adds a day or two. So if I'm doing an ultrasound and I'm a little bit out from my measurement, I'm only going to be changing typically that due date by a day or two. Different as we have a chat about the growth scans and fetal weights because those areas are quite high, whereas the error for the earlier gestations are quite small because typically all fetal poles are very similar in size for the early gestation.
Mel:
[14:39] So are there any instructions that women need to have before heading off to their scan morning of? Do they have to do anything to prepare?
Phil:
[14:47] Yeah, I think so. I think you get told to come with an absolutely full bladder drink a liter of water, which I think it's difficult because everybody's differently hydrated. I recommend people come to their dating scan with a full bladder. Now, why? Because the bladder acts like a nice little window for us to look through. So sometimes helpful, sometimes not, but you can't fill it up very quickly. So it's always good to start with a full bladder. Now, a full bladder isn't one that's excruciatingly painful. It's that feeling you get first thing in the morning. When you wake up, you're like, oh, I need to go to the toilet. That's about as full as I need you, but no, I'm not about to explode. So you'll get a standard preparation from the clinic on how much you're supposed to drink to get a full bladder, but that's one size definitely doesn't fit all. And I really feel bad for patients coming in, particularly if I'm running late and they've got a 10 o'clock appointment and it's 10, 15, and these patients are sitting in the chair thinking that the world's about to end because they're about to wet themselves. So please just come with a bladder that's full, like you would be sitting at home going, oh yeah, I need to go to the bathroom.
Mel:
[15:47] And then the sonographer is going to push on your bladder while they do the ultrasound. Is that right?
Phil:
[15:52] Yes, a little bit. Exactly. So hence, more important to come with a bladder that feels full but not really painful.
Mel:
[15:59] So you shouldn't be busting like you're trying to hold your wee in the whole time through the ultrasound.
Phil:
[16:04] Because often it doesn't help in any way. So it's a good window, the bladder. But once it gets too full, it actually pushes the uterus further away. The bladder is here and then the uterus sits behind. But if the bladder is too full, the uterus is even deeper still. So it becomes a little bit harder to see in that circumstance.
Mel:
[16:21] Okay. But you're right about the running late thing because women take seriously filling up their bladder and then they time it for when their ultrasound is. And if you're running 20 minutes late, that's a long time for a full bladder.
Phil:
[16:34] Yeah. And I have complete empathy. I had a renal ultrasound. And I remember thinking, I'll help these guys out so much and I'll just keep drinking heaps of water. because I figured the more water I drink, the better clear image you get. And they were running late. And I literally thought I was going to explode on the spot. So I have a huge empathy for these women saying that, yeah, you definitely don't need an exploding bladder. It's just comfortable.
Mel:
[16:59] So for this one, it's about determining approximate due dates as closely as you can. Seeing that there's a viable pregnancy in that the baby has a heartbeat. Seeing if there's more than one baby in there. We can check if there's any bleeding associated with the pregnancy and the possibility of ectopic pregnancies and, Have I ticked all those off, the most of the things that you're looking for in this ultrasound?
Phil:
[17:29] Yeah, anything else is just sort of incidental. So things like you might see some uterine anomalies like a fibroid. You might see some ovarian pathology. That's all incidental.
Mel:
[17:38] So it's not just about finding out the dates of the pregnancy because I certainly have clients who are like, and I know when I got pregnant, I don't need that first scan. And certainly they might not feel like they need the rest of the information either, but it's more than just about finding out when your due date is.
Phil:
[17:56] Yep, that's true, yeah.
Mel:
[17:57] So then the next ultrasound option, assuming that nothing is concerning with that pregnancy, so assuming women haven't had any other symptoms or issues, is the nuchal translucency ultrasound. So this one is considered less routine. So a dating scan seems to be part of routine maternity care.
Phil:
[18:19] I don't know whether that's patient-led or provider-led, to be honest, but I feel like you would know the answer to that statement more than I would in that circumstance.
Mel:
[18:27] Sure. So you're just sort of going, right, whoever comes in with a referral, that's what we do. So it's up to the care providers to be sending women for ultrasounds that they believe that they need.
Phil:
[18:37] That's correct. I mean, to obtain a Medicare rebate, you need a valid clinical reason. Yeah.
Mel:
[18:44] And then from there on, there's some optional scans. And the nuchal translucency sits in the sort of optional basket. And there are some other options. So if anybody doesn't want the nuchal translucency ultrasound, but you do want to get some information that that nuchal translucency ultrasound can offer, there's another test called the NIPT N-I-P-T test, and it's a blood test, which can give some information. So there are some women who opt for the NIPT over the nuchal translucency, or sometimes They'll do a NIPT and a Nucle Translucency. So let's talk about what this Nucle Translucency offers because it's an ultrasound and a blood test. And there's a pretty clear window for this one. You can't just go any time for a nuchal translucency. What's that window?
Phil:
[19:34] So the data set is actually from 11 weeks gestation to 13 weeks and six days. In saying that, we typically don't do the scans until about mid-12 weeks to mid-13 or towards the end of the 12th week. The reason being that these scans, we look at a lot of the early anatomy of the baby and it's a bit difficult to see that early anatomy than four and a half to sort of early 13th week. And so that's why we try and get these women to come in around about sort of the 13th week, at the beginning of the 13th week is a good time to come. In terms of what the scan can show, would you like to sort of have a bit of a discussion on that?
Mel:
[20:12] Yeah, let's do that. But I just know that some women kind of, they go, oh, yeah, I'll book it, I'll book it. And I'm like, no, no, you know, there's a pretty, there's a small window for this one. you can't go and get that done at 16 weeks or 17 weeks. This is, yeah.
Phil:
[20:26] Yeah, that's right. Because, I mean, what's the overall goal? The overall goal of this scan is to determine what kind of risk the baby carries for chromosome problems like Down syndrome. And the data set stops at 13 weeks and six days for that risk assessment.
Mel:
[20:41] Right. So, okay, why would a woman go and get this nuclear translucency scan? What do we find out?
Phil:
[20:47] It's for people who want to know what kind of risk the baby carries for a chromosome problem. and it's based on four factors. So it starts with your age and a high-risk result is regarded as being a risk that's one in 300 or greater. So starting with the patient's age, we would then have a look at a few features on the ultrasound and they would be the thickness of the fold of skin behind the baby's neck called the nuchal translucency. Babies with chromosome problems typically have a much thicker fold of skin behind their neck. We have a look at the baby's nasal bone, so a little bit of calcification sitting on the baby's nose that babies with chromosome abnormalities like Downs and Drame typically don't have. So we want to check that that's present. So that's three factors. So we've got age, nuchal translucency, nasal bone. And then the fourth variable we look at is a blood test. And that blood test looks for a couple of hormones in mum's blood and babies with chromosome problems. Their placentas are abnormal. And so the placentas will secrete these two hormones in different concentrations into the maternal bloodstream than a baby who doesn't have a chromosome abnormality. So they'll check those two hormonal levels and making sure they're in normal concentrations. Fulted skin's normal, nasal bone's normal, blood test is normal, and hopefully that risk factor will go from 1 in 250 to 1 in 2,000. Or if the factors are a little bit worse, then it would go from 1 in 250 to 1 in 100, 1 in 10, 1 in 4, depending on how bad things are.
Mel:
[22:13] And those two hormones, because we check PAPA and...
Phil:
[22:18] Free beta HCG, yeah.
Mel:
[22:20] Free beta HCG. So those are the two hormones that you'll check with the blood test that goes along with the nuchal translucency ultrasound. So you need all those four factors. And I, again, am assuming that they get thrown into a computer program that spits out a risk ratio result.
Phil:
[22:36] That's great.
Mel:
[22:37] So you might get a risk ratio of one in 3,000, one in 250. And so what this tells me is that the nuchal translucency ultrasound is a screening tool, not a diagnostic tool.
Phil:
[22:51] That's correct.
Mel:
[22:51] And so women would use that information. They would use their result. So let's say they got a result of they have a one in 300 chance of their baby having a genetic abnormality. They could use that information to make a decision about what diagnostic strategy they wanted to take or how could we find out if I am the one or if I'm not and so for those we're not going to really cover them in detail because it's not the idea of today's episode but if you do get what's called a high risk result on your nuchal translucency one option is the NIPT test the NIPT blood test They used to do amniocentesis and choreovilus sampling, but I believe with the introduction of the NIP test or the Harmony test, that's going out of fashion a bit.
Phil:
[23:45] So yes and no. So the NIP test does look for fetal DNA within maternal circulation. So we know that the babies will...
Phil:
[23:57] Their own DNA into mom's blood and someone very clever figured out that they can actually see that fetal DNA within maternal blood and then screen it for chromosome abnormalities, which is really cool, up to 99% accuracy. The NIP test tells you to some degree whether, to fairly reasonable accuracy, whether the baby's got a chromosome abnormality. However, it's still not, it's still regarded as a bit of a screening tool to some degree and the only real diagnostic tool are your CVS or your amniocentesis because that's when they can look at the full range of the fetal chromosome and DNA structure to look for particular genetic malformations in that circumstance. So say, for example, if you get a high-risk nuchal translucency, the question would be why did you get that high-risk nuchal translucency because what things did they see on that scan that pushed you over? And then they might do a NIPT test and that might come back normal.
Phil:
[24:55] And then you'd have to have a conversation with your healthcare provider about whether that's the end of the screening tests or whether there were some things that were found on the nuclear translucency scan, which still warrant further investigation. There might be other genetic problems that we can detect on an amniocentesis that the NIC test won't pick up. And we think that your baby may have it because of this structural anomaly that we're noticing. So, for example, like a brain abnormality, there are some significant structural anomalies that we can see at 13 weeks, may not come up, might get a high-risk nucle, might get a normal nip, but then they still may move on to an invasive diagnostic test.
Mel:
[25:37] So that would be a discussion to have based on your personal, individual results with your healthcare provider, particularly because, you know, the amniocentesis and the CVS sampling is quite invasive. You know, they're actually...
Mel:
[25:50] You know, it's not a blood test or an ultrasound. There's needles involved. That comes with their own risk. So that's the nuchal translucency. Again, you can choose, obviously you can choose not to have any of these. But for families who are sort of thinking, I have no interest in understanding the chromosomal makeup of my baby, mm-hmm. Then this test might not be necessary.
Phil:
[26:14] Let me pause. I'll go back one because there's a bit of a circumstance that we missed. The nuchal translucency scan is a chromosomal risk assessment, but it's also an early anatomy scan. We're going to talk shortly about the 19-week scan and what we can see there. But a lot of the anatomy that we're seeing at 19 weeks is starting to be brought back to that 12, 13-week mark when we do this nuchal translucency. So although it is a chromosome abnormality test, it is still an early anatomy scan where we can detect things like brain problems, early heart problems, limb anomalies, herniation of the gut, all sorts of things we can see at the 12-week scan. Another thing to be mindful of is that the NIP test, often people will get that around 10 weeks, can still have a nuchal transluency or an early anatomy scan after that NIP test if people want to jump to the NIP test around that early mark because the NIP doesn't really tell you about the structural features of the baby. So it'll tell you whether the baby's got a chromosome abnormality or not of the top three. So trust me, 21, 18 and 13, but it doesn't tell us whether the limbs are normal, the brain's normal, all that sort of thing. So it's still important to be mindful that if your clients are going for an NIP test, that an early anatomy scan might still be indicated to look at the baby's anatomy a bit early on.
Mel:
[27:35] So, in terms of the practical costs of these things, I imagine the dating scan is cheaper than the nuchal translucency scan. Is that correct?
Phil:
[27:45] Yeah, it depends. So, really, unfortunately, I don't know why, but obstetric ultrasound is very poorly rebated under the MBS. So, I work in general radiology. I can scan your finger for a lump and get more from Medicare than I do for a dating scan or a nuchal translucency, which I think is... Yeah. I know, it's odd.
Mel:
[28:12] I mean, they're long scans. It's not like a three-minute ultrasound or anything.
Phil:
[28:16] The government sees Medicare rebates. It doesn't poorly rebate screening. It prefers diagnostics. So, if anything's screening, it won't sort of rebate it very well so yes so unfortunately the rebate it's very low um so typically not everybody but typically there's a gap charged in that circumstance to try and cover the cost of the scan um you can get a place that bulk bills everything i'm sure you can find them around they're few and far between these days but you can go anywhere from bulk billing to getting charged i mean up to probably 150 for that scan but then for the nuclear translucency that that's significantly increased in terms of how much out of pocket typically, but I've seen anywhere up to $500 for that scan. Majority average would be around somewhere between the $150 to $200 mark for that scan.
Mel:
[29:04] And I mean, I'm a private clinician, so all of my clients have their ultrasounds at, you know, radiology clinics. But I think that women who are having care through a public hospital might be able to book their scans through that service and then avoid the payment.
Phil:
[29:21] Some. So it depends on the hospital. So perinatal ultrasound, they'll draw the line at certain things. So they'd have to be super duper high risk often to be able to be accepted in particular at a hospital, because you can imagine the need would be huge if they were opening it to every scan involved, really, you'd have to be inundated. So I think they had to draw the line at certain reasons for certain things. So often they get screened at a general radiology practice, something's found, and then they'll get moved on to the hospital.
Mel:
[29:52] You'd be right, actually, because you wouldn't even start. Often women have had the dating scan, the nuchal translucency, and a morphology scan before they even get to book into hospitals for their maternity care, because a lot of the early care is done by GPs or midwives or if they've managed to find themselves an obstetrician. So that's something for women to know as well is that there's most likely going to be an out-of-pocket cost to whichever ultrasound options that you choose. So that's the dating scan, which is, you know, optimal timing around eight weeks. The nuchal translucency scan, which is optimal timing around 13 weeks, and that has a blood test. When women come with their nuchal translucency referral, Do you guys do the blood test there at the clinic as well?
Phil:
[30:38] Every clinic is going to be a bit different in that circumstance. Majority outsource it to a pathology company. So I've worked at clinics that post out the referral for the blood test to the patient before the examination so that they can come to the examination for their ultrasound and have their blood test already done and so the results are all finalized on the day. And I've worked for other clinics that give a pathology request to the patient on the day to go have it done and then the results will be postponed until that pathology result comes back.
Mel:
[31:07] Right. But from a clinician's perspective, we give a referral for the nuchal translucency and then you guys, from the point of care when they come for their nuchal or when they book it, you guys will work out the blood test logistics.
Phil:
[31:20] Yeah. And I think maybe we skipped over that as well. Before we do this, I'll have a good discussion with the patient about what the results mean and whether it's something that they want to know. Because often, as a care provider, we'll just send the patient for this scan and the women's like I'm here for my scan and they're like okay well what do you why do you think you're here and then they really don't have any idea so then we run through everything that this scan is going to show and and some people don't want to know that information and so we do a quick scan for for you know early anatomy and then they don't do the risk factors because they don't want to know in that circumstance and so we wouldn't do the blood test in that circumstance
Mel:
[31:56] Do you find that that's common that women just come because they've been given their referral and they're not truly understanding yeah.
Phil:
[32:04] All the time
Mel:
[32:04] Yeah okay all right so that's yeah I think that's a unique part of my work is that often women will only get what they absolutely want and so either I give them all the information I can or they come already having the information but I can see that it would happen in for example a quick GP appointment where the woman comes in and the GP goes right we do a b and c for anybody who thinks they're pregnant and here you go have your ultrasound and we can just diligently go off. Yeah. The other thing I assume though, Phil, is that you're quite vigilant. That's been my experience of you as a clinician. Imagine that not all sonographers are the same though. There must be a collection of sonographers who receive the referral, go ahead with the scan and thanks for your patronage and see you later.
Phil:
[32:54] Ah, yeah. So, yes. So, the... The skills and experience of sonographers are vast. It's a hard one to get into because it's such a big field that, yeah, we are responsible for finding problems. And then that diagnosis is made by our obstetrician, gynecologist or radiologist. And so not just in our skills from a clinical perspective and how well we can do that side of our job, There's such a vast amount of variance and skills and experience in talking to patients and being able to communicate with patients in a way that makes them feel comfortable and informed before their examination. So, yeah, it's just one of those things where I try really hard. But, yeah, there's definitely a big variance in the skill set of sonographers. is.
Mel:
[33:51] I mean, I think that's the same across all healthcare fields. All right. So let's move on to the next ultrasound option. Again, assuming there's been no complications and we don't need to check anything else. And this is probably the most common scan that women will receive in their pregnancy. They certainly could forego the dating one if they don't need any of that information and they feel really confident. Again, with the nuchal, the morphology scan, for me in particular, if I have clients who are particularly selective on their ultrasounds and they say which one do you think is the most important I think I will always choose this morphology scan as a clinician particularly in my field where I'm usually going to be looking after women in their homes.
Mel:
[34:38] And this morphology scan I feel gives the most information the most helpful information for maybe what they can expect in terms of outcomes after the birth for their babies. That's just kind of where I'm seeing it's not necessarily accurate. But this scan's done between usually 18 and 20 weeks. Here's what I talk to my clients about is that, again, it's an anatomy scan. So you'll check all the body systems and organs and make sure that they're all there and in the right place and potentially functioning properly. You can see the kidneys functioning and bladder functioning in that one among other things you can check the position of the placenta and also the cord insertion at that time.
Mel:
[35:26] Amniotic fluid volume the length of the cervix and is that it, What else do you look for at the morphology scan?
Phil:
[35:37] There's lots, yeah. So it is an anatomy scan. So first and foremost, we spend the majority of our time looking at the baby, checking that every part of the baby looks normal from an ultrasound perspective. So we look for the brain, the spine, the limbs, the chest, looking at the heart, looking at the abdomen, just making sure that any structural issues are not present. And that list is growing every year because the ultrasound systems are getting a little bit more detailed and our skills are getting a little bit better. And so we're finding things that we potentially wouldn't have seen a few years ago. The placenta and the cervix are definitely something that we want to look at very closely. And you said before that it's a good scan to look for potential changes to outcomes of the pregnancy. And I think that's certainly correct. you've come across patients that have had placenta previa and that's an important diagnosis to make at that particular start time or vasoprevia where the umbilical cord runs behind the membranes over the cervix and then you've got some some fetal outcomes which would change the way that the where the baby would potentially need to be born to have early care like heart conditions diaphragmatic hernias because it can significantly affect the outcome of the pregnancy but at birth or even sometimes before. Short cervix, yep, certainly something will screen.
Mel:
[37:02] This is the one where you can find out the sex of the baby. If women don't want to know but they want... There to be a record like can they do things of like don't tell me but leave it on my record what the baby is and then they could find out later.
Phil:
[37:16] So even even if someone if someone doesn't want to know the gender of their baby we will still look at the area we write we have televisions in the in our rooms for the obstetric room so i'll essentially just turn off that tv and be like i'm gonna look at the gender now because i still look at the area for for all my patients not because i want to rub it in that I know when they tone, but just to check it looks relatively normal. I mean, there are some, a few little conditions which can be present at the 19 weeks camp, but typically we don't record that on the report unless there's an abnormality.
Mel:
[37:51] And I think the importance of this one for care providers is it helps to plan the future needs and screening and care of the woman. So I've certainly had circumstances where the baby's had a heart defect and we've realized we need to have more scans, engage with more healthcare providers, potentially make a change as to whether or not you're going to have your baby at home, birth center, hospital, whether the baby needs to be born early via some other way. And in terms of the position of the placenta, and this is one thing, we've got a podcast about this as well, a few podcasts actually on placental position. But the reason it's important to know about the placental position is there are some women who can't have their babies vaginally because of the placement of the placenta. But also, there's a growing number of women who are planning vaginal birth after previous cesarean sections. And so if the placenta is implanted over the scar and then actually abnormally implanted in the scar and you're planning a VBAC and we detect that, I mean, that's a huge bleed risk at the birth. It can be quite life-threatening. So, again, if we're seeing those kinds of things in this morphology scan, it's an indicator for a different care pathway. Are you guys in the habit of checking previous cesarean scars at that morphology scan?
Phil:
[39:21] Yes and no. So, if there's been a cesarean previously, we can see the scar, typically. If the placenta is anywhere near that scar then we will have a look and see if there's any signs of placenta accreta so that's where the the placenta abnormally adheres to the the wall of the uterus and invades the wall of the uterus it's a very tricky diagnosis but i think at the very least there has to be some investigation and potentially some comment about where the placenta is in relation to the scar so that the right people can exclude that diagnosis i think that's probably the step one it doesn't matter how good you are as a as a clinician in terms of diagnosing this particular condition because it is a very serious one the fact that you can just have that little mental check like this has this patient had a cesarean yes okay where's the placenta it's anterior okay well the scar is on typically on the anterior surface of the uterus where is the placenta in relation to the scar okay what's it closed so i don't know much about placenta or crita but at least if you can say hey it's close to the scar then that patient can potentially be seen by someone who knows how to look at the findings for placenta grita and diagnose that a little bit more carefully in that circumstance.
Phil:
[40:33] And this is what I love about the fact that I can call you and have a conversation about patients because I really value having that sort of direct feedback to professionals. I would call you and say, listen, I'm not the be-all end-all when it comes to placenta or a crater. I can see that this placenta is near that cervix, but please send it on to the hospital or a federal medicine to have a really good look at it and to exclude it and go from there.
Mel:
[40:59] Yeah, the morphology scare, often they're just completely fine. You get the result and you get great this is all normal we also it also will tell you the fetal weight.
Phil:
[41:08] Uh yes yes it does it does yeah so it's not the main thing we'd be looking at in terms of weight i really try not to comment with bubs measuring a week ahead now and that doesn't matter the main the main problem is the week behind or the lack of growth and baby measures a week behind or more, then we would flag that for people like you to have a bit of a discussion about whether there's some issues with the placenta and also there's a risk for aneuploidy or chromosome animalities if the baby's measuring a bit small. But in terms of weight, we do have it. It's just more of a, is it within a normal range or is it small?
Mel:
[41:53] Because during the ultrasound, you record the size of the head and the abdomen and the legs. Is that all the measurements that you do?
Phil:
[42:02] For the morphology scan, there's a few more anatomically, like we do a few more brain measurements and things like that. But for biometry, for weight and for growth, head, tummy and thigh.
Mel:
[42:12] Yeah. And again, I've seen there's some computer program that you enter all that data into and it spits out a fetal weight estimate.
Phil:
[42:21] That's correct, yeah.
Mel:
[42:22] So for those out there, just know we don't usually make clinical decisions based on the fetal weight estimate at the 20-week ultrasound, nor do we worry about the position actually at this stage. So, yeah, I've had rare occasions where, for example, the baby's been breached and in the scan, the sonographer recommended review at 28 weeks due to fetal position. And I'm like, just ignore that line. So you know position of the baby weight of the baby at this stage the other less important things these seem to this scan appears to be more interested in how things are functioning and developing to see if we need to do any further screening or follow-up or making plans for the how do you tell about the function of the placenta at this age mainly.
Phil:
[43:16] Function of the placenta would be the baby's size. If we're seeing a very small baby at the morphology scan, then the placenta could be a problem. Doppler is where we look at how things move. And during obstetric ultrasound, we use Doppler to measure many things, heart rate, and one of the other things that we use it for us to see how blood moves through the umbilical cord. And so even at that early 19, 20-week mark, We can use Doppler to see whether things are looking okay, but namely the appearance of the placenta, which is subjective, and the baby's size are the two things that we screen at that 19-week mark to see how the placenta's going.
Mel:
[43:58] The other thing that just occurred to me as you were talking about the cord is you'll report also on how many vessels are in the cord. So there's usually three, but sometimes there can be a finding that there's two vessels in the cord. That's the morphology scan. And theoretically, and I believe this is the current guidelines for age natal care in Australia, is that if the morphology scan is normal, low risk, and there's been no other issues through your pregnancy, this will be the last scan you would routinely be offered during your pregnancy. So once you've had this one... Nothing else to do unless there's a complication.
Phil:
[44:33] Yes, in Australia, that's correct. So it's only if the clinician has discovered some clinical concern that they would continue with another scan.
Mel:
[44:42] So some things that I can think of that women would be offered multiple other scans after this. For example, on the nuchal translucency, the ultrasound, the PAP-A result, if there's a low PAP-A, there's been some correlation with placental function in that. and there's a thought that the baby's growth could be affected over the pregnancy. And so I've seen women be offered routine growth scans and maybe like 28 weeks and 36 weeks in addition to the morphology scan for a low pap A. So they're called serial growth scans. Are you looking for everything again that you do in the morphology or is it just the size?
Phil:
[45:23] Just generally the goal of the examination is to figure out how the baby's growing and to see things like cord flows and fluid around the baby there is a limited assessment through the anatomy you can see some some developing changes in that third trimester that are sometimes difficult in the second trimester to see so certainly i still screen through the anatomy and myself if i haven't done the scan or even i have i will just do a quick little assessment each time the baby comes through just to in the amount of times in what 17 years that I've seen just random things on a scan where I just had a bit of a sideways vision and had a look and I wouldn't have seen otherwise yeah there's heaps heaps of heaps of things that I've picked up particularly things that make a big difference like the biggest one would be a couple of heart defects where someone else didn't quite see it at the 20-week scan and
Mel:
[46:10] So these growth scans I'm also thinking of women for example if they've been diagnosed with gestational diabetes, if they have a history of intrauterine growth restriction. The growth scans seem to be the biggest sticking point for women. Because they find that their care providers make decisions based off the results of the growth scans. So, for example, the scans are showing that the baby's slightly larger or a higher centile on the chart. Clinicians will take that ultrasound and go, right, you need an induction or you need it. You know, they're making decisions based on the findings of the ultrasound. Do you have any comment about, should we be doing that off a single ultrasound or even a series of ultrasounds?
Phil:
[46:55] See, that's tricky because I can't comment on that because it is your expertise in that circumstance. We are just a tool to give as much information as possible. Again, as I said, we are just this tool for clinicians to use to give you as much information as you would like and we hand it back to you guys.
Mel:
[47:14] Yeah. Do what you will now. I suppose it's kind of like, not exactly, but, you know, asking the person who's collecting your blood to tell you what you should do next if it finds that you're anemic. It's like, well, that's not like, yeah, I'm just here to tell you what your hemoglobin is, all right? So I guess that's the role. And that kind of leads me into one of my other points is that I've had women come and, you know, women report that they'll have a scan at the sonographer and the sonographer go, whoa, this is a huge baby. You're going to need a cesarean section or hey you know yeah you got twins uh you know wow or this baby's breech that means it's a cesarean section that's i mean a clear overstep of the scope of a of a sonographer so for women who are out there listening if you're sitting in there having an ultrasound and the sonographer makes a comment about maybe a clinical strategy of what to do next that is, Yeah, well out of their scope, well out of their training even. They're just kind of giving you their own personal opinion. It's not a medical opinion.
Phil:
[48:19] I don't think it's appropriate that a sonographer discusses what the results of their findings mean for the rest of their pregnancy. So it takes a little bit of life skills and a bit of wisdom, a bit of experience on how to manage those conversations with patients, knowing your boundaries to know when not to say something.
Mel:
[48:38] Sometimes it can be really serious. You know, they found a serious anomaly with the baby, and this has been part of my clinical experience where they've found a serious anomaly with the baby. And I've had a sonographer say to the woman, oh, this anomaly is not compatible with life. And it's like, whoa, you can't say that. In fact, that baby is still alive and did survive. But the woman left her ultrasound thinking that she wasn't going to have a live baby, and that wasn't the call of the sonographer to make. So I think, you know, when I talk about this to women about, you know, don't take any of those conversations seriously in a sense is that that's not their expertise of the sonographer to be making those conclusions.
Phil:
[49:22] I think it's important to mention that there is a problem to some degree or get the radiologist to come in or the obstetrician to come in and do that. I think that's the first step is for us to have a discussion with our reporting physician, so whether it's a radiologist or obstetrician, and then not let the patient go without knowing something because I may not be seeing someone for weeks on end or there might be some need to get some feedback or some other tests done soon. and so just letting the patient know that they've found something with the body region so that they can get that followed up pretty
Mel:
[49:59] Quickly yeah just kind of like hey don't wait don't wait till your next appointment for this one here's a question there's some women who want part of an ultrasound but not other parts say the morphology scan okay so i certainly have had clients who've said i'm happy to find out the placenta position i don't want any scan on the baby or vice versa yes you can scan the baby's anatomy but I don't want to know the baby's size or and my usual experience with, most sonographers is that they say look your care provider sent you for morphology scan I've got to do a full morphology scan uh you know I make a note on there please do not scan this this this and this upon request of the woman but what's the I mean what are the rules around that if yeah.
Phil:
[50:47] So so firstly the scan has to meet medicare criteria for medicare rebate so let's just just cover that the purpose of the scan has to be very clear and meet particular outcomes to achieve medicare rebate so that's just one conversation to have because if it doesn't then they'd be paying privately for that particular scan but if i was to come across that scenario i'd have to call you and have a conversation about what what's the what's the story here where is this patient sort of coming from here and what do we need to achieve to get from this. I would have a conversation. I would never restrict someone access from a scan because, I mean, if they want, yeah, I just have to have a conversation with you and the patient. If you send me one, I'll be scratching my head going, oh, my goodness, I don't know how to go with this. Because, as I said, my goal is that I'm information giver, right? If you restrict the information that I'm to give you, it's just like my heart goes,
Mel:
[51:43] Oh. I can't do it. I want to give you all the information. Yeah, I want to give you everything.
Phil:
[51:48] Yeah.
Mel:
[51:49] Yeah. I mean, I suppose, you know, if it's maternal preference where they have some particular ideas about the impact of the ultrasound on their baby and they think, look, I'm happy to have a scan on the placenta, but don't scan the baby. That's, I guess that's one of the pain points that I've witnessed is that women go in and say, I don't want to have a scan on the baby. I just want to have a scan on the placenta. And they say, well, your clinician sent you for a morphology scan, so I have to do the whole thing. And that makes sense, given that you guys are the collector of information that you then pass on, and the clinician is saying, please gather this information. Yeah. Well, let's move on to kind of, now we're moving into more scans that are in response to clinical pathology. So after your morphology scan, if you haven't got any other routine scans planned, the next ultrasounds are going to be based off the woman's or the baby's health needs. So there's been times where I've sent clients for an ultrasound that I was never planning on sending them to but it were in response to what I was noticing by what I felt with the baby or measured or something during our age natal care and I would send a woman for like a general well-being scan like I feel something different please tell me what's in there, For those scans, what are you looking for? Because I know there's a biophysical profile, so maybe talk us through that, but also what else, what do you guys check?
Phil:
[53:16] So there's a bit of a routine scan regardless of what the reason is during the third trimester. If a patient comes in for a third trimester scan, this is what they get. They get a growth scan, so we'll determine the baby's size through measuring the biometry of the head, abdomen, and thigh. We have a look at how much amniotic fluid is around the baby, and it's a subjective measurement where we look at all four quadrants of the maternal abdomen,
Phil:
[53:42] Our lower pelvis, and measure the depth of fluid in each of those quadrants and come up with a figure that tells us whether there's enough amniotic fluid around the baby or not. We look at the flow in the umbilical cord to make sure that there's not an increased resistance. So blood gets pumped from the baby's heart through the umbilical cord towards the placenta and we can put a little Doppler signal on that and see whether the placenta is resisting the baby. So if there's increased resistance from the placenta back towards the baby, and that would be a concern. We can look at the biophysical profile. Now the biophysical profile is a very subjective thing. It's a score of eight. it gets a score of two for having a normal amniotic fluid it gets a score of two the baby's doing breathing movements even from early on the diaphragm will contract and you'll see these breathing reflexes happening and then you've got great movements so movements of entire limbs rolling if we see two of those movements that's given a score of two and then you've got tone which is the finer movements like flexing the fingers tonal movements around the mouth moving It's a score out of eight, each one giving a score of two for each of those four parameters. And it's a tricky one.
Phil:
[54:58] Biophysical profile is probably more of a, like I just doing it long enough where I'll look at a baby like, I haven't seen this baby move, like all scan. And I'll come back to it and then I will say to some, back to a clinician saying, listen, this baby is not just not moving like normal. And that's a tricky one
Phil:
[55:14] because it's such a subjective thing. It requires a lot of experience. The biophysical profile was a great idea, but it's a very tricky one to execute.
Mel:
[55:23] Okay.
Phil:
[55:24] In that circumstance.
Mel:
[55:24] So do you think it's a more subjective idea of the well-being of the baby?
Phil:
[55:29] That particular parameter, yes. So biophysical profile is only a small percentage of the overall scan. So look at placenta position as well. But biophysical profile is a subjective, it is quantitative in terms that you have to quantitate the movements of the baby, but you're actually looking at the baby for those movements and that way it is subjective. But in that circumstance, generally I'll... With the experience that I've got, I'll just, and you see babies day after day, you know ones that move and you see ones that don't, and you can sort of just, that flags prick your ears up. It's like, yeah, we call it the sonographer intuition where you're like, something's just a little bit odd about this baby. And then you'll sit and spend a little bit more time with the baby. But the biophysical profile, it does have a specific protocol that you try and follow, but yeah, it is a bit of a subjective one.
Mel:
[56:13] And with the AFI, the amniotic fluid index, so you said you measured the four pools, amniotic pools but that was it is a fairly subjective measurement what makes it subjective so this is a yes.
Phil:
[56:27] Let's think about a true quantitative analysis of the amniotic fluid so if you could have an mri through the uterus and they could get the volume of liquid around the baby from a three-dimensional mri then that would be a quantitative analysis is that you can see the actual volume of fluid around the baby. We don't do that. And what we do is it's a mixture of qualitative and quantitative analysis, right? Because you're, as a sonographer, trying to find the deepest pocket in each of the quadrants and measure them. And that will give you a centimeter score. Less than five centimeters is regarded as being oligohydromycinetic or less than normal. And then you've got polyhydromycinosis, which is more than 25 centimeters. And there's always a bit I have an error score myself for borderline measurements because I always find that having absolute thresholds means that you miss some. And so, I will have, say, 20 to 25 where I'll just sort of, again, use that intuition and have a look and is there any reason for maybe why I'm seeing a little bit more like auto-normal. And then from five to eight centimetres, again, is that borderline sort of result where I just want to check in my, and I'll do it a few times just to be sure in that circumstance. But it is a bit subjective because you have to find The baby's moving, pockets are variable.
Mel:
[57:43] Well, that's good information for women to know because, again, clinicians will use results to make decisions about things, particularly for women with gestational diabetes or women who are post-states. The amniotic fluid volume starts to become a really important clinical piece of information and women will say, oh, my doctor says I've got to be induced because my AFI is five.
Mel:
[58:09] So knowing that it's subjective means for example if you really want to avoid something but I mean obviously women don't want to not have care that they actually need for their baby but if they're not sure if they're feeling like that this could be a thing that a second opinion might be helpful for considering it's a subjective measure so that's good information so it's basically you're Measuring the approximate fluid in four places, again, that gives you an idea of a score. But, again, an experienced clinician might have an intuition about how much is actually there. What? Have you heard of this? I've seen it on a few scans. It actually hasn't materialized as anything, but they make comment about how opaque or how the amniotic fluid is. And I've had a sonographer suggest that that was because the baby had done a poo. It was meconium stained lycol. This was again a post-state scan. So the woman was coming close to 42 weeks and they were kind of giving us a list of all the reasons why the baby should not stay in there and see that the amniotic fluid's cloudy. That means there's meconium stained lycol. Can you actually see that?
Phil:
[59:20] So we can see the lycra, and it all goes down to every day you see things that are normal and things that are different. So I have come across a couple of circumstances where I've looked at the lycra and gone, that's very bright. We're talking about the 1% or the less than 1% where it looks very unusual. But when the lycra is very bright, I would have to ask the question, even up to fetal medicine as to why that is. One of the things they need to exclude in that circumstance is has there been any bleeding into the amniotic fluid because blood will sort of tend to brighten up the amniotic fluid so that would be something that they would have to investigate a little bit further but it's again we were talking about subjective things right so my bright to someone else's bright is a little bit of a different scale because you know i've been doing it for maybe a little bit longer than that person i'm not too sure um but having a little bit of debris within the amniotic fluid is normal very common as for meconium i don't think you can tell in that circumstance if that was that was the truth i think we would have that conversation if i said if it came across a very bright i mean the fluid i'd have to say i don't know why and i think the federal medicine guys would have to run through all the options in that circumstance but i would not certainly say anything other than this is very unusual it
Mel:
[1:00:34] Can confirm that that wasn't mconeum say like or because the birth happened and it was normal so you know that was like oh there was nothing there okay so that's the well-being ultrasound the final one i want to ask you about, and this might be for a small proportion of women who are pregnant because a lot of women get induced closer to 42 weeks certainly the clients who I care for are hiring me because they want to avoid that kind of thing so I'm in the habit of doing a post-dates ultrasound so somewhere within that 41st and 42nd week doing an ultrasound to check which babies are going to cope with going over 42 weeks. One thing that I've come across with the post-state ultrasound and the clinicians have commented is particularly on the size of the baby is that they're not going to be able to be able to be able, where the computer program, and correct me if I'm wrong, but they say something about is basically the computer program doesn't have a formula to be able to calculate the weight or size of a baby beyond 41 weeks. So the result that I'm getting, they kind of like take that with a grain of salt in terms of the size of the baby. Can you comment on what do they mean by that?
Phil:
[1:01:44] Sort of. So the data sets should have percentiles for all, but they won't have weeks. So, if I've got a patient that comes in at 40 weeks plus three and the baby's a bit bigger than average, on the ultrasound system, it won't say anything greater than 41 weeks. I'll just be out of range for each individual measurement. So, say the head might be measuring 42 weeks or it doesn't really have that in the data set. It has a percentile chart, which we'll talk about shortly. So, you might notice that a bit of the biometry is out because you'll see a whole list. This head measurement usually relates to a 38-week plus four or something like that. But because it's out of range, it just is out of range, it still will assign a percentile typically to that circumstance across all four.
Phil:
[1:02:27] And then it will spit out a percentile on a weight regardless of how far along Bub is or how big Bub is. So it still will, but there is an error. Yes. Now, the reported error is somewhere between zero and 20%. So that's huge, right? The reason for that error can be to do with the sonographer. So the way that the measurements have taken can be due to the baby's position, not getting accurate representation of those barometric measurements. And it can be to do with the formula as well. If the heads and the abdomen and the thigh sort of don't match in percentiles, sometimes the error factor increases a little bit in that circumstance as well. But typically, all post-dates should get a weight and they should get a percentile if it's requested. So post-dates scans aren't always biometry. I often will get a post-dates scan, which is AFIs and flows only. So we don't have to do the size of the baby if that's not requested by the clinician. So if you were to send a lady to me at 40 weeks plus and say, I just want to know the AFI and flows because they affect the outcome in the short term, then I would do that. without having to do the while and drink.
Mel:
[1:03:39] Okay, because that's important. Really, in terms of understanding the well-being of the baby, at 42 weeks where you've got a baby that you know is physically put together as it should be, then knowing the AFI and the Doppler flows, those are indicators of placental well-being. That's the thing that we're thinking about at 42 weeks is how well is the placenta functioning. And if there was poor placental function, we would see a reduction in the amniotic fluid volume.
Phil:
[1:04:14] Yeah, you would. You'd also sort of see a reduction in baby size potentially. If we did a post-state scan and the cord flows were off, I'd either call you and say, hey, do you want me to just do a full biometry so we can get like a bit of a bigger picture here about what's going on? Yeah, it would definitely, having a look at the cord flows is definitely the way that we determine whether that placenta is doing well. And whether, yeah, and the amniotic fluid also is to some degree if all that functioning is going well and the placenta is doing its job when there's not a lot of amniotic fluid around, that's because the baby typically isn't urinating very much and so the placenta can be the problem in that circumstance. But then you'd also ask the question, has the mother been licking any amniotic fluid? And that's sometimes hard to tell or be told.
Mel:
[1:04:58] So, yeah. Yes. Yeah, that's right. All right.
Mel:
[1:05:01] I've got one more question. What do you know about the potential dangers and risks of ultrasound? Because we've spoken a lot about what we can find and all the benefits of all that information we can find. What are the risks and potential dangers that women should be aware of when they show up for an ultrasound?
Phil:
[1:05:25] So a lot of research has been done in that sort of space of ultrasound and its risks. So, the vast majority, up to this point, they've done research on outcomes from a child perspective and noticed no difference in the childhood outcomes in high ultrasound populations versus low ultrasound populations. And then you go back to the research that's been done from a perspective on animal models and things like that and they have noticed that ultrasound that is done with amplitudes higher than diagnostic levels can cause some cavitation and what they call bipolar formation in that circumstance. So, in theory, there are some concerns about ultrasound but not
Phil:
[1:06:14] Nothing's been shown to be present with the level of ultrasound that we use for diagnostic purposes. But in saying that, there's still recommendations out that ultrasound is a tool to be used when it's needed and not when it's not. That's the sort of overall statement from everyone in that circumstance. There's been nothing proven to be harmful at the levels that we currently use. There are some theoretical concerns at levels and powers that are like it's an amplitude of the ultrasound higher than we use for diagnostic purposes and there's been shown to be no difference in outcome from a childhood perspective and that's just my own little research but i i sort of disclaimer right so i want to make sure that everyone does their own right from from reputable sources does their own look around has makes up their own opinions there's no right or wrong way to go about it, but I do want to make sure everyone goes and does their own research and asks good sources, good questions about what's needed and why is it necessary.
Mel:
[1:07:15] Yeah. So the general consensus is don't use it more than you need it for your purposes. It's not kind of just a fun activity for, you know, when we hear all the stories about the obstetricians who every time a woman goes into their clinic, they've got an ultrasound machine sitting there and everyone gets a scan every visit and it's like, woo, are we, Are we doing any damage as a result of that? That brought up another question. I realized we didn't even talk about, like, how does ultrasound work to even get a picture? I mean, is it?
Phil:
[1:07:48] Jeez, you're going to take me back to physics. Okay, I think I'll try. I'll try.
Mel:
[1:07:52] Well, I mean, what's the premise? How does it, like, you know, obviously a three-minute summary of the whole thing.
Phil:
[1:07:58] So it's like a best way I could equivalent. It's like a fancy fish fighter, essentially. The way it works is it sends out a sound wave. And the way that it works is there's a crystal on the transducer. Now, the transducer is the probe that we hold, the line of crystals that sit on that. And when you apply an electric current to those crystals, those crystals slightly expand. And when you take that current away, they contract. And so, they apply the current to these crystals at a certain frequency. And that frequency is then, or the sound waves, which is higher than audible. So, you're looking at, say, for pregnancies, it's somewhere between 1 megahertz to 10 megahertz. I assume you can't hear them, but I did a little test with a kid that was like, oh, can you hear ultrasound? I'm like, no, no, you can't hear it.
Phil:
[1:08:46] And then I put my probe down to the lowest frequency that you can and then put up to my ear, I'm like, oh, maybe I can barely hear it. And then this kid goes, oh, let me hear it. And he goes, whoa. And so maybe you can hear it, but I'm older and then you can't sort of hear it. But typically, regardless of frequencies, you can't actually hear. And so those sound waves will get transmitted through the tissues and they get bounced back. Every time a sound wave hits a different interface, some will get reflected back up to the transducer. And that reflection forms an image, essentially. So sound waves go down, and then at various levels, they get reflected back at different amplitudes, and the computer will then create an image from that, yeah.
Mel:
[1:09:31] Wow. So it's high-frequency sound waves that bounce off whatever you're trying to scan and bounce back, and then the computer creates an image.
Phil:
[1:09:41] Yes, based on that. Just like radar, yeah.
Mel:
[1:09:45] Well, there you go. And what you're saying is in between that 1 and 10 megahertz, the research is saying that in that frequency, they can't see any reason why that would be of danger.
Phil:
[1:09:58] Yeah, frequency and amplitude as well. So there's power behind, like decibels, right? So there's power behind sound as well. So you can set out the frequency, like you can set it out with very, very little power and it just doesn't go anywhere. Or you can really crank up the power and those frequency would come through. So the powers that we deal with diagnostic purposes haven't been shown to have any effect that we know of.
Mel:
[1:10:20] Yeah, sure.
Phil:
[1:10:21] Sorry, I can't again, I've got to be careful because I don't have the full knowledge of every research article across everything in the world. So I encourage everyone to do their own research, yeah.
Mel:
[1:10:33] Great. Amazing. I don't think I have any more questions about ultrasound. I mean, we could keep going, but we are restricted to reasonable podcast length. Phil, thank you so much.
Phil:
[1:10:45] You're welcome. Thank you very much for having me.
Mel:
[1:10:47] To get access to the resources for each podcast episode, join the mailing list at melaniethemidwife.com and to support the work of this podcast wear the rebellion in the form of clothing and other merch at thegreatbirthrebellion.com follow me mel @melaliethemidwife on socials and the show @thegreatbirthrebellion all the details are in the show notes.
This transcript was produced by ai technology and may contain errors.
©2025 Melanie The Midwife
