62. Ep. 331 – Dr. Emiliano Chavira – Umbilical Cords – Informed Pregnancy Podcast
Elliot: Welcome to the Informed Pregnancy and Parenting Podcast. I am your host, pregnancy-focused chiropractor, Dr. Elliot Berlin. My guest
Elliot: Welcome to the Informed Pregnancy and Parenting Podcast. I am your host, pregnancy-focused chiropractor, Dr. Elliot Berlin.
My guest today needs no introduction. He’s an old, classic, and favorite guest on the podcast. He’s an OB-GYN and Maternal Fetal Medical specialist here in Los Angeles. We have some incredible episodes together talking about things like pregnancy over 35, and the arrived trial.
Today, we’re talking about umbilical cords. What are they? How are they formed? What are some of the variations and complications, and what do you do about them? Dr. Emiliano Chavira, welcome back to the podcast.
Emiliano: Thanks so much for the invitation. It’s been a while. You know, when you pitched this topic to me. It really struck a chord.
Elliot: Oh, wow! All right. Let’s jump into it. First of all, your background. Just in case anybody has been under a rock. You are an OB-GYN, did and specialize in Maternal Fetal Medicine. That means that you do a deeper, more closer analysis of things that need a steeper looking at. And then, whereas most of you stop delivering babies to sit in your office and look at MFM evaluations all day, you still love to go catch them.
Emiliano: That’s right. And the Maternal Fetal Medicine, it focuses on what some people understand is high-risk pregnancy. Although, I kind of despise that term, it involves things either it’s maternal issues maternal complications maternal medical conditions or it’s fetal things. It involves a lot of ultrasound. So, it’s a very ultrasound-heavy specialty, which is very relevant to the issue of assessments of the umbilical cord.
Elliot: Is it true that you can get an ultrasound that attaches to your iPhone?
Emiliano: Yeah. There are devices where there’s a handheld ultrasound probe, and then it Bluetooths to your phone. I’ve never used one, so I don’t know how good the quality is but they are out there.
Elliot: Wow! That’s pretty cool. I wonder if they’ll make that for hands for chiropractors. We can remotely, like you guys do the surgery with the gloves.
Emiliano: I’m sure it’s a matter of time.
Elliot: The robot, yeah. Because a lot of people, during the pandemic, work from home. I tried. Nobody wanted to lay down on my dining room table and get their little crack and stuff.
Emiliano: That’s only because you never invited me.
Elliot: Wait. You’ve been.
Emiliano: That’s true.
Elliot: Come back. All right. Let’s talk about the cord, the umbilical cord. Tell me in basic understanding of where does the cord come from, when does it develop, how is it made.
Emiliano: The umbilical cord is really the lifeline for the fetus, or the baby, during the pregnancy. It’s the connection between the mother, or the pregnant person, and the fetus. I think most people know that the umbilical cord is attached to the baby’s belly button, and then the other end of the cord is attached to the placenta, which is also attached to the uterine wall. And that’s where the vascular connection is between the baby and the mother.
So, the mother’s circulation flows into the uterus and it brings nutrients and oxygen into the placenta, which diffuses across into the fetal bloodstream that happens in the placenta. And then, this blood that’s rich in oxygen nutrients flows through the umbilical cord to the baby, bringing all this stuff to the baby, and it flows in through a single umbilical vein. Then, the baby uses up all the good stuff, uses the oxygen, produces carbon dioxide, uses up the nutrients, and produces some waste products. And those flow back out through the umbilical arteries, back down the same umbilical cord, back to the placenta, and back into the maternal bloodstream, and then the mother gets rid of those waste products.
If you think about it the umbilical cord has to develop from the very, very beginning of the pregnancy because it’s the lifeline to the fetus. Pregnancy starts off as a single cell, and then it doubles, and then you got four, and then eight, and 16, and turns into this mass of cells which eventually separates away from the placental disc. And you have this connecting stock, which over the next few weeks, will develop into the umbilical cord which contains vessels. That happens between like the third and the seventh weeks of pregnancy. By the time you get to the seventh week, you have a formed umbilical cord.
Elliot: Wow. It’s mind-blowing. All the pieces of this whole thing, whoever puts us together, is mind-blowing.
Elliot: But how that cord forms just the right way between the two parties and nestles itself in. Even just the whole idea of a placenta that you kind of make it a little command post for the nine months, and then just spit it out. It’s like disposable human organ.
Elliot: It’s very cool. Okay. The umbilical cord. I remember this back from a long time ago when I was studying anatomy and physiology. These umbilical arteries and veins are different than the like backwards to all the other arteries and veins in the body, right? Because arteries always carry blood away from your heart.
Elliot: They generally have oxygenated blood in them.
Emiliano: Right. After birth, you think of children and adults, your heart pumps oxygenated blood that runs through the arteries, out to the tissues, and then the tissues use up that oxygen. And then, the deoxygenated blood runs through the venous system back to the heart. And so, in the umbilical cord, it’s the opposite. Because oxygenated blood is running through a vein, returning from the placenta back to the fetus. And then, the deoxygenated blood is pumped from the fetus through arteries back towards the placenta.
Emiliano: So, it’s backwards in the cord.
Elliot: That’s a little backwards. That explains my whole upbringing somehow. All right. Sometimes, when the cord forms, things don’t go exactly according to plan. Before we get into the different variations or complications that can happen, are there any things to do or not do to encourage a healthy cord?
Emiliano: I think the development of the cord — I’m not really aware of anything that a pregnant person could do to influence that. I think that just sort of the workings of Mother Nature and it’s going to happen how it’s going to happen. I think all you would really do is focus on healthy pregnancy behaviors, eating healthy, getting exercise, good night’s sleep, stress management, regular chiropractic treatments with Dr. Berlin.
There’s an interesting phenomenon that happens in early pregnancy, maybe from like week 7 to 10 or 12. The little fetal intestines are forming, the small intestine, large intestine, and they actually herniate into the umbilical cord for a period of a couple of weeks. You can actually see this on ultrasound.
Emiliano: Sometimes, it gets mistaken for an anomaly. Because you see this mass in front of the baby’s belly, but it’s actually part of the normal physiologic development of the fetus. This is called “physiologic herniation of the gut into the umbilical cord.” It’s thought to be that this is part of the way the bowel rotates inside the abdomen. There’s a normal rotation that happens.
And then, the intestines will all slide back into the abdomen, exit the umbilical cord, and development proceeds as normal. I’ve seen this multiple times where somebody looks at a fetal ultrasound and they see this mass and are concerned that it’s a birth defect, that it’s an anomaly. The patient gets referred to maternal fetal medicine, and everything later looks normal. It’s because what they were looking at at the time was this physiologic herniation of the gut in the umbilical cord.
Elliot: Well, that’s really interesting. So, when would you say that you said around seven weeks?
Emiliano: Yeah. Seven to 10 weeks, seven to 11 weeks, that’s when you might see that.
Elliot: In that early ultrasound, are you looking for any kind of evaluation of the cord or is it still too small?
Emiliano: You might be able to assess whether you have two arteries. Not necessarily looking at the cord, but you can see the arteries inside the fetus. They’ll be surrounding the bladder. In the first trimester, you can assess for the presence of the normal two arteries. But the cord itself is pretty hard to look at that early on.
Elliot: Okay. Well, let’s jump into the variations. But first, a little break. We’ll be right back. You don’t want to miss this.
Elliot: Welcome back to the Informed Pregnancy Podcast. We’re talking about Dr. Emiliano about the wonderful umbilical cord. All right. Tell me more about the normal anatomy of a cord.
Emiliano: Okay. A typical umbilical cord will have a single umbilical vein and two umbilical arteries. The vein tends to be larger than arteries. The vein is also a little more compressible, the arteries are stiffer. And then, surrounding these vessels, the vessels are running through this extracellular matrix, which is this gelatinous type of tissue called “Wharton’s jelly.”
Emiliano: The function of that is to protect the cord to protect the vessels in the cord against compression. So, as the baby’s moving around, and swimming around, and flipping around, interacting with the cord, the blood flow through the cord is not impeded from compression because it’s protected by the Wharton’s jelly. The cord tends to end up somewhere between 50 to 60 centimeters long. That’s pretty typical length. The other thing is it winds, it twists. So, when you see an umbilical cord, it has this twisted structure almost, you can imagine like a telephone cords. People, remember telephones with cords?
Elliot: Oh, yeah. I remember them getting tangled all the time.
Emiliano: Yeah. That’s a typical cord.
Elliot: It’s a little convoluted.
Elliot: Interesting. Okay. That’s a typical anatomy of the cord. Then, you have some variations and some complications from mild, where would you like to start?
Emiliano: Well, we could talk about those basic structures because there’s variation there. One variation that we commonly see is what’s referred to as a “single umbilical artery,” or sometimes two-vessel cords. So, instead of two arteries, there’s just one. One of the arteries either never forms correctly or it fades away, and it’s a fairly common finding. We might see this in 1 to 2% of pregnancies. If it’s one out of 50, I might, in the course of the week, see that every two or three days.
Elliot: Oh, wow. Out of curiosity, is the artery that does exist, is it bigger than a typical other?
Emiliano: No, it’s about the same.
Elliot: So, it can do the job?
Elliot: Like having two kidneys?
Emiliano: Yeah. It actually usually does the job just fine. So, when we have a single umbilical artery, there’s a few things we look for. You have to look very carefully for other birth defects, other malformations. Because sometimes, single umbilical artery occurs in the setting of other birth defects. And so, if you find that, that’s a more complicated pregnancy. It can be seen sometimes in association with certain chromosomal disorders; like down syndrome, trisomy 21, or trisomy 18. We’re usually very interested in what the genetic screening test results are for this particular fetus. But if there’s none of those other findings present, and everything else is normal, and you just have a single umbilical artery, those are usually healthy normal babies.
If you read the medical literature, you will see that there’s an association between single umbilical artery and growth restriction. On a certain superficial level, that may kind of make sense. Like, if the cord is what’s supporting delivery of oxygen and nutrients to the baby, and if the cord is not normal, maybe that baby’s not going to be able to grow normally. But in reality, I see so many single umbilical arteries, and a vast majority of cases, these babes are fine. They grow fine. They do fine.
Elliot: If the other tests are negative, is there anything different to do other than just keep an eye on them?
Emiliano: Keep an eye on them, that’s really it. Usually, we would perform serial ultrasounds over the course of pregnancy to just keep track of the growth and make sure there’s not a problem with the growth. Like I said, they usually grow fine. Some people might do this fetal monitoring in the end of the third trimester. Some people call it “antepartum testing.” Some people call it “non-stress test,” fetal surveillance. But, basically, it involves a quick ultrasound to check the amniotic fluid, make sure that’s normal. And then, you listen to the fetal heart rate for about a 20-minute period. And if those two findings are normal, that’s considered a reassuring fetal test.
Elliot: That’s kind of interesting. Because the arteries are taking blood away from the baby. You would think if there was some sort of decrease in capacity to do work bringing blood into the baby that would be a more substantial concern.
Emiliano: But it’s a circular flow, right? It’s a circuit.
Elliot: Something logical.
Yeah. So, that is single umbilical artery. At what point do you usually diagnose it?
Emiliano: Typically, that would be identified at the fetal anatomy ultrasound, which tends to happen in the neighborhood of about 20 weeks.
Elliot: Oh, that neighborhood.
Emiliano: Yeah. You’ve been there.
Elliot: I’ve been there, yeah. Okay. So, someone [unin 14:51]. If my summary here is correct, in the absence of other things, just wait and see. But, probably, going to be okay.
Emiliano: Yeah. It’s a pretty benign finding in general, I’d say.
Elliot: Sweet. Where do we go from there?
Emiliano: The next thing that we would look at typically is where the umbilical cord inserts into the placenta.
Emiliano: Typically, you would expect the umbilical cord to attach the placenta somewhere in the central region.
Elliot: Okay. What’s the quick overview of the placenta shape or structure?
Emiliano: They tend to be disc-shaped. Although, sometimes they can be ovoid. And sometimes, you can see what are called bilobed placentas. Almost maybe if you think about like a figure of eight, or an infinity sign.
Elliot: Oh, yeah.
Emiliano: Or a snowman.
Elliot: Snow person. Is the shape, does it mean anything?
Emiliano: I don’t think it has much significant, clinical importance.
Elliot: Okay. Even though like the bilobed? Because, sometimes, if you just hear things like that, I was like, “What? Is that a problem? Is that a concern?” They’re different shapes, different varieties.
Emiliano: Yeah. In general, I think so.
Elliot: Okay. Let’s say, just for visual, it’s a disc shape. There’s the outer part of the disc, and the inner part of the disc. You’re seeing the cord normally attaches somewhere towards the inner part.
Emiliano: Yeah. Or if you were to picture a target. There’s the outer blue ring, and then the red ring, and then the bullseye is the yellow ring in the center. The cord will attach somewhere in the center.
Elliot: Okay, yeah. When you said target, I was picturing only white and red rings.
Emiliano: That’s Target.
Elliot: Oh, so sorry. I didn’t understand. I’ll put it in the subtitles. That’s right. All right. We’re back. Okay. So, we’re looking for the cord to be towards the middle of the target. I guess there’s sometimes variations where it isn’t.
Emiliano: Right. Sometimes, the cord will insert closer to the edge of the placenta rather than in the center. We would call that a “marginal insertion.” You see that maybe 10% of the time, something like that. You might see it more commonly in twin pregnancies. That has been associated as well with growth restriction and preterm birth. However, what I would say about all these ultrasound findings, when you really start to dig into the medical literature, you find that the literature is somewhat scant, mixed results, and probably a lot of unaccounted-for confounders. In general, I think maybe more is made of these variations than really should be.
Elliot: You think the exit polls might be wrong?
Emiliano: I think it’s something to be thoughtful about. Mindful of the quality of the data could be better.
Elliot: Well, so many questions. First of all, you said twins. Is there sometimes two cords going into one target?
Emiliano: Yes. Let’s set twins aside for a moment.
Emiliano: But, yes.
Elliot: Tweaked my curiosity.
Emiliano: But, yes, absolutely. There’s the marginal cord insertion. And then, even more abnormal than that, sometimes the insertion point is actually not on top of the placenta. But it’s in the membranes somewhere adjacent to the placenta.
So, if we use our target example, you have the yellow ring, the red ring, and the blue ring. Well, you shoot the arrow and it doesn’t hit any of the rings, and it misses the target completely and hits the haystack that the target is hanging on. So, it’s off to the side somewhere. The importance of that, picture a thin tree and as the trunk reaches the ground — because you know that’s how trees start, right? They’re in midair and the trunk grows down toward the ground. When it hits the ground, then the roots spread out from there in all directions, right? You picture that.
The same thing happens with an umbilical cord. The cord is floating through the amniotic fluid, makes contact at the placental surface, and then branches out into vessels that then traverse across the surface of the placenta in all directions. All right? If you picture that example of the tree with the roots. Usually, that point where the tree is touching down the ground should be on top of the placenta. But in these cases, it’s off to the side. And then, the roots are running through the membranes to reach the surface of the placenta.
Elliot: Wow, okay. They’re not anchored quite as well?
Emiliano: Well, that’s exactly right. Because they are not protected by the Wharton’s jelly that’s in the cord itself. And they’re not on the placental surface, which you know also provides some protection of those vessels. So, they’re kind of these naked vessels running through the amniotic membranes, and they’re unprotected. This is probably a higher-risk situation than some of the other variations that we talked about. This is referred to as a “velamentous cord insertion.”
Elliot: Where’s that terminology from?
Emiliano: My guess, I mean it sounds like “velo sale,” the term “sale.”
Elliot: Okay. I thought like Velma from “Scooby-Doo.” Okay. So, velamentous, velamentous cord insertion. More concerning than the marginal cord insertion.
Elliot: Marginal cord insertion goes into the placenta the way it’s supposed to just off to the side rather in the middle.
Emiliano: Off the side, right.
Elliot: And the velamentous cord insertion doesn’t quite really —
Emiliano: Really off the placenta.
Elliot: Right. And then, the tentacles kind of make its way over there. Do they tend to run small?
Emiliano: There does seem to be some correlation with growth restriction. But it’s the kind of thing where you have a higher chance of seeing poor fetal growth than the general population. But it’s also not a guarantee that that’s going to happen. Most of these pregnancies will be normal. I’ll give an example.
One study that compared birth weights of the infants in this cohort of pregnancies found a low birth weight about 4% of the time. And when there was a velamentous cord insertion, it was closer to like 15% of the time.
Elliot: Oh, wow!
Emiliano: You know, three or four times higher. But on the other hand, that still leaves 85% of babies that were normally grown.
Elliot: With the velamentous cord insertion.
Emiliano: With the velamentous cord insertion.
Elliot: Right. Okay. One of the things — one of the many things that I love about is you present data, and then we can process it rather than just opinion.
Elliot: Thank you for that. So, with velamentous cord being a little bit more concerning, are there things during that pregnancy that one would do differently?
Emiliano: Well, there’s no formal published guidelines that I’m aware of. I think most Maternal Fetal Medicine Specialists would recommend serial ultrasounds. Since growth restriction is more common, you want to keep a close eye on the growth. If you do find a growth-restricted baby, those fetuses are at higher risk of stillbirth than the general population. So, it’s a finding that if it’s there, it’s worth being aware of it and probably increasing your monitoring. And then, whether or not to do the fetal testing that we talked about, the antepartum testing, that’s probably a matter of some controversy. In a baby that’s normally grown, it’s probably going to be a lot more controversial and there will be probably universal agreement if the baby’s growth restricted then you’re going to do the antepartum testing.
Elliot: With velamentous cord, it sounds like maybe jostling would be a bad idea. Is there any sense of like don’t be overly active or work out?
Emiliano: I think anybody that makes that kind of recommendation, it’s not evidence-based.
Elliot: It’s just like your brain thinking, “Maybe it’s a good idea.”
Emiliano: Maybe it’s a good idea. But in the history of medical interventions, a lot of ideas that seem like good ideas. Once you study them, didn’t pan out so well. You know me personally, just as a matter of philosophy, I, in general, try to avoid making recommendations that don’t have a good evidentiary basis.
Because on the other hand, there’s so much. If you tell a pregnant woman or a pregnant person that they need to start restricting their activity, well it’s very clear there’s tons and tons of research regarding the health benefits of physical activity, and exercise, and movement in pregnancy. If you restrict those things you may be potentially doing harm, and who knows whether there’s really any benefit to that or not.
Elliot: I know. I always have patients that are in some sort of restriction or modification along the way. And our patients love to work out. They get not just physically, but mentally, I think a little bit drained or sad that they can’t work out. And so, to make them feel better, I always commit to not working out also. So, they won’t be the only one.
Emiliano: That’s a 10 out of 10 on the empathy scale.
Elliot: Thank you so much. That’s why I get my 2-star up on reviews. All right. There’s a lot more cord here to talk about, to record. So, we’re going to take another break. We’ll be right back.
Elliot: Welcome back to the podcast. We’re talking to Dr. Emiliano Chavira. We were just talking about the velamentous cord insertion, where the cord doesn’t quite make it all the way in, solidly into the placenta. But it’s nearby and its little tentacles make its way in unprotected, semi-protected. There are different categories of that.
Emiliano: You can picture an umbilical cord that inserts like a centimeter away from the placental disc, as opposed to one that’s 3 centimeters away, another one 5 centimeters away. The farther away it is from the placenta, probably, the more dangerous that is. There’s a particular version of this that actually is very high risk, and it depends on where in the uterus the cord is inserting into the membranes.
If the cord is inserting adjacent to the placenta, somewhere up top near the uterine fundus, that’s a safer situation than if this happens down low somewhere close to the cervix. The reason for that is, when you eventually go into labor and the cervix start dilating, at some point the membranes are going to rupture and tear open. Sometimes, that happens spontaneously naturally. Sometimes, it’s done by the care provider artificially. But the membranes will rupture at some point or another. If there are fetal vessels running through the area that ruptures, those vessels can be torn. At which point, the baby’s just going to be bleeding into the uterine cavity, and the fetal blood volume is pretty low. So, it doesn’t take long for blood loss in this situation to become life-threatening for the baby.
So, when the vessels are running through the membranes between the umbilical cord and the placenta, and that is down low close to the cervix, that situation is referred to as “vasa previa.”
Elliot: What do you do about it?
Emiliano: There is some good news on this front. This is a scenario where the natural state of things, without medical interventions, this is associated with a pretty high rate of fetal loss. The survival of babies in this situation, when you don’t know the diagnosis, may be something in the neighborhood of like 60% or so. There’s a lot of fetal loss.
But when you know the vasa previa is there, typically, what happens is these moms are admitted to the hospital in the third trimester, and they are subjected to intense fetal monitoring. Usually, multiple times a day. And then, the fetus is delivered early, maybe somewhere in the neighborhood of around 34 weeks.
Elliot: Oh, really early.
Emiliano: By cesarean section.
Emiliano: And when you have this intensive monitoring and medical management, the survival jumps up to something like 97, 99%
Emiliano: That’s very, very high. In obstetrics, there’s so many things that we don’t have good success stories. This is one diagnosis where you can really make a big impact.
Elliot: Wow. So, I guess people should go for regular OB checkups.
Emiliano: I mean, there are a lot of diagnoses that you might make with ultrasound that, in the end, you don’t really change the life trajectory of the baby significantly. In other words, if you discover the issue after birth, that’s just as well as you know discovering it in big pregnancy. But this is one of those exceptions where it makes an enormous difference to discover that situation and then manage it appropriately.
Elliot: Is that anywhere near or similar to a funic cord presentation?
Emiliano: Okay. Cord presentation is a different issue because vasa previa is fetal vessels that are running between the umbilical cord and the placenta. Those vessels are attached to the membrane. They’re running through the membranes. A cord presentation, or a funic presentation, is the umbilical cord that’s free-floating in the uterine cavity, finds itself down low above the cervix, between the baby and the cervix.
Emiliano: Or it could be adjacent to the fetal head, but it’s somewhere down low in the uterus. So, the risk there is when you labor, first of all, if the head mashes down on top of the cord, that could cause some cord compression. As you’re laboring and having contractions, and the baby’s sort of being pushed down onto the cervix.
The other thing that can happen is as the cervix dilates, and as membranes rupture, and as fluid flows out, the umbilical cord could sort of what we call “prolapse,” it could sort of fall out. And that can be a hidden cord prolapse. It may not be obvious. This is called an occult cord prolapse, which is maybe like adjacent to the baby’s head in the birth canal. But it hasn’t come out so far that you can feel it on exam or aware of it. You can have these occult cord prolapses, and then you can have a complete Frank cord prolapse, where a loop of cord comes completely out of the vagina and is sort of dangling there between a mom’s legs.
Elliot: That is dangerous?
Emiliano: Well, it depends.
Elliot: That may be dangerous.
Emiliano: In certain settings, it’s dangerous. When you have a term pregnancy, fortunately, this cord prolapse is pretty uncommon. They happen on occasion, but there’s pretty infrequent complication. But you have a term pregnancy and the baby is coming head first. In that situation, cord prolapse is a dangerous problem. Because the cord gets compressed by the fetal head. And so, blood flow circulation, oxygen delivery to the baby is cut off. And there are studies that show a very clear correlation, the more time it takes you to deliver that baby, the higher risk that the baby is going to be injured or even not survive that. Well, so it’s a time-sensitive emergency. There are certain breach presentations where cord prolapse may not necessarily result in cord compression.
There are studies looking at cord prolapse and the time interval between when the prolapse is diagnosed and how long the baby takes to be born. And there is actually not that much of a correlation between how long the cord is out and adverse outcomes. It’s because if you have a specifically complete breach presentation where you have the fetal butt and the fetal legs, there’s sort of places where the cord can pass through and not necessarily get compressed.
So, that little factoid is really only relevant to breach birth providers. In most obstetricians, they only do vaginal birth in head-down babies. And so, certainly, in that situation, cord prolapse is a dangerous complication. Usually, that’s treated by emergency cesarean section in most cases.
Elliot: Oh, as soon as they see the cord?
Elliot: But you’re saying for breach, if you have a bum down baby, it’s not as big a concern?
Emiliano: It depends on a specific type of breach. If you have a Frank breech, that means that it’s just the baby’s butt down there, it acts just like a fetal head. It completely fills –With a Frank breech cord prolapse is equivalent to a cord prolapse with a head-first baby. It’s a dangerous complication and you probably need to go right to the cesarian section. But if you have a complete breach, it may not result in cord compression the way it does with other presentations.
Elliot: Okay. Completely, the butt down but the legs are also down.
Emiliano: Right. Correct.
Elliot: Okay. But getting to the funic cord, is that something that you generally wouldn’t deliver vaginally?
Emiliano: In most cases, you probably wouldn’t. You would have to have a way of moving the cord, and I don’t know that there’s a real, obvious easy way to do that. Just sort of trying to think outside the box, maybe doing some kind of inversion exercises, and seeing if you can get things to shift around inside the uterine cavity. But you’d probably have to luck out for that cord to move out of the way. I’m not sure there’s a technique that could reliably move the cord out of the way for you. So, you’re probably delivering by C-section is the safest way to go in that scenario. Fortunately, that doesn’t happen too commonly.
Elliot: Oh, that’s good. Is there other presentation issues with the cord? I mean, besides like the cord presentation being down or the ones that we talked about. Are there any other places where the cord would be a concern?
Emiliano: There’s the issue of the nuchal cord, right? Where the cord’s around the fetal neck.
Emiliano: It’s a very, very common finding. In a term pregnancy, we’ll see this in one out of every three or four births. When you talk to the general public about this, there’s a lot of awareness about the existence of the phenomenon of the nuchal cord. And there’s a lot of anxiety about it, I found in general. That somehow, it’s very natural to perceive this as a dangerous circumstance.
Elliot: Well, I think if we picture ourselves with a cord around our neck.
Emiliano: Yeah. It’s funny because, for so many years as an obstetrician, my automatic thought was that people are concerned about compression of the cord. If it’s around the neck, you can compress the cord. It never dawned on me what people are worried about is asphyxiation of the baby because there’s something around their neck.
Elliot: Right. That they’re not breathing.
Emiliano: But they’re not breathing. They’re not breathing through the mouth or through the nose. They’re breathing through the umbilical cord.
Elliot: Not through the airway. So, if the airways compress —
Emiliano: I guess in theory, if you compress the neck hard enough, you have to press vessels that are going to the brain, the carotid arteries. I mean I think if it was that tight, you would probably also get some compression of the cord itself. But the real concern is compression of the cord. Because like we said, the baby’s not breathing through its nose and mouth the way we do, the oxygen is coming in and out through the umbilical cord. It’s entering through the belly button.
Elliot: And it has all that Wharton’s jelly.
Emiliano: It has all that Wharton’s jelly. There’s some science that is very well established about what happens when the cord gets compressed. And it’s reflected in the fetal heart rate. There are very immediate changes in the fetal heart rate that you see if something compresses the cord.
And so, let’s say a normal fetal heart rate is somewhere in the range of 110 to 160. Let’s say, it’s a little baby’s heart’s beating along 130 beats a minute, something squishes the cord, the heart rate slows down to 90 beats a minute. And then, when you release the compression, the heart rate comes back up to 130. When you see this traced out on a piece of paper, it looks like a V. The heart rate drops down and comes back up. That’s a very reliable physiologic response. If something compresses the cord, you see what we call a “variable fetal heart rate deceleration.”
So, conversely, if there is no deceleration, then you know that there’s nothing compressing the cord or obstructing blood flow through the cord. There’s a very interesting phenomenon you’ll see a baby born that may have the cord wrapped around its neck once or twice. Rare case is maybe even more. You look at the fetal heart racing during labor, and there just wasn’t much of any cord compression going on.
Elliot: So, it’s designed for that, seemingly?
Elliot: Is it more concerning, like a three or four-time wrappage?
Emiliano: I don’t know if I’ve ever seen any studies on that.
Emiliano: You might think, intuitively, you’ve got a higher chance of having some cord compression with higher degrees of wrapping around, but I don’t really know specifically.
Elliot: Sometimes, the cord’s just short.
Elliot: And you see sometimes, the baby will come out. Instead of going to the chest, they go to the belly because —
Emiliano: Can’t reach.
Elliot: Yeah. The new extension cord. But could it be too short for them to come out?
Emiliano: I don’t think so. I’ve never experienced anything like that. I have experienced cases where the cord was so short that the baby couldn’t move away from the perineum. I mean, it’s literally that short. The baby could be born, but move no farther. I saw that happen once on a twin birth.
But a lot of times, people are thinking conceptually about the cord holding up the baby, preventing the baby from descending, preventing the baby from moving. But the thing that you have to keep in mind is that cord is not attached to a fixed structure. In other words, it’s not attached to the maternal ribs. That as the baby’s moving down that cord is not moving down. The cord is attached to the placenta, which is attached to the uterine wall, right? So, as the baby’s moving down, and the uterus is contracting and pushing everything out, everything is coming down together as a unit. As the top of the uterus is pushing down towards the maternal pelvis, the placenta is also coming down where the cord is coming down. Everything is moving as a unit. That make sense?
Elliot: Yeah. I can picture the analogy, but I can totally see it. It doesn’t really matter if the cord is short if the thing it’s attached to is moving along in the right direction.
Emiliano: Moving with the baby, yeah. I think for a cord to be so short that the baby couldn’t actually make it out the birth canal would have to be an extremely uncommon scenario. I’ve never seen anything like that or read any case reports like that.
Elliot: What about a knot?
Emiliano: Knot is pretty common. We see those here and there. I don’t really know a percentage, but it might be 1% of the time, half a percent of time. Whereas, the babies moving around and swims through loops, and the cord gets tied into a knot.
Elliot: Again, my logical brain says, “Okay. If the main thing is compression, a knot doesn’t sound ideal.”
Emiliano: It’s going to depend on whether it’s pulled tightly or not. If it’s loose, and again, the umbilical vein and the arteries are protected by this Wharton’s jelly, then blood will flow through there just fine. In fact, most of the time, we see a knot. It’s an incidental finding that was never seen on ultrasound. We discovered it at the time of birth, and the baby’s fine. There may be some cases where the knot gets pulled tightly, and then impairs flow through the cord. But that’s something that doesn’t happen often.
Elliot: At the end of the birth, when the baby comes out, people now talk about delayed cord clamping. Do you have thoughts on the idea?
Emiliano: I do. I think it’s a misnomer.
Elliot: Okay. Well, let’s talk about what it is.
Emiliano: Yeah. Okay. In traditional obstetric teaching, you show up for training and your senior resident teaches you how to catch a baby, the baby is born. And then, shortly thereafter, within a matter of seconds, you clamp the umbilical cord and you cut it. Basically, detach the baby from the mother. And then, the baby goes wherever. It goes to the baby warmer, to the mother, wherever it is. But you’ve separated the baby, the mother. And then, you start dealing with delivery of the placenta.
Historically, the cord is clamped immediately. Well, it’s become very apparent with multiple studies that that’s not the ideal management of the cord at the time of birth. There’s a certain amount of blood contained in the placenta that gets transfused into the baby after the birth, and that has some beneficial effects. And so, the current thinking is you should not clamp the cord right at the time of birth, but you should allow that natural transfusion to happen. And then, the cord gets clamped at a later point in time. Whether that be a minute, five minutes, 10 minutes, whatever the interval is. That’s the concept of delayed cord clamping.
Elliot: You’re not into it?
Emiliano: No. I think it’s a euphemism that if you describe “delayed cord clamping,” that sounds like it’s a maneuver. “I’m going to do something new for this birth. I’m going to delay cord clamping, and this is going to confer benefits on your baby.” Well, if you look at premature infants, the difference is tremendous. There’s like a 25% difference in intraventricular hemorrhage, which is bleeding in the brain. It’s one of the really dangerous complications that happen in preemie babies.
The way I think is appropriate to look at this is it’s not the delayed cord clamping that is a new maneuver that confers benefit, it’s at the way we were doing it previously which was premature cord clamping that’s causing harm.
Elliot: [unin 42:36]. Okay. So, you’re very into delayed cord clamping.
Emiliano: I’m very into delayed cord clamping.
Elliot: You just don’t like what it’s called?
Emiliano: Yeah. It obscures the fact that our traditional practice was harmful.
Elliot: Right. I see. You almost remind me of Mitch Hedberg, who used to say, “Why do we call it corn on the cob? That’s just been called corn. It’s the corn when we take it off the cob, that we did something to it.” Right? Anyways. I’m wondering anyway, none of the other animals take out a clamp and go for the cut right away. I wouldn’t do everything they do, like eat the baby. But, sometimes, we can learn from them.
Elliot: I have another very important question. What determines the innie or the outie?
Emiliano: Yeah. I don’t know. I think that’s something that is not determined by the cutting of the cord.
Elliot: Right. Okay.
Emiliano: Eventually, you cut and clamp the cord at whatever time point that is done. You leave a little bit of stock of umbilical cord. And so, that might be an inch or something like that. Eventually, that dries up, it desiccates, and it falls off. And then, the baby’s belly button is remaining. I know, sometimes, people will blame that on the care provider. That they didn’t do this cord right. But that’s really just Mother Nature.
Elliot: As always, when I have you on the podcast, I’ve learned so much. You could even tell by my line of questioning. Like, I don’t know anything about the cord. But now, I do. So, thank you.
Before we wrap it up, is there anything that you wanted to add that we didn’t cover?
Emiliano: I think the main thing is so many of these topics in these issues, and the experience of pregnancy itself is so anxiety-provoking. Particularly, with things like nuchal cord. I’ve seen women who were told by their obstetrician that it was dangerous to labor. They were delivered by cesarean section because of the presence of a nuchal cord seen on an ultrasound. It’s just absolute nonsense. It is heartbreaking that the natural process of birth and childbirth was interrupted and transformed into surgical birth over an issue like this. But it happens fairly commonly.
That’s not to say that the nuchal cord is never ever, in any instance, going to be a problem. In rare cases, it may be a problem. But if you’re going to do a C-section on every single mother that has a baby with a nuchal cord, that means we’re going to do a C-section on one out of every three to four babies for this reason. And then, you got to think about all the complications that we’re going to get from all those cesarean sections. So, we’re really just going to create a lot of complications that don’t need to happen trying to avoid this one rare case.
I think, in general, people need to feel comfortable that these things are safe. They’re not dangerous. You don’t need to have a C-section because of a nuchal cord. In fact, honestly, what you need to do is just sort of ignore that finding. Pretend like nobody ever knew about it, and just treat the pregnancy as normal.
Elliot: That’s what I do with my liver enzymes.
Emiliano: There you go.
Elliot: So, Doc, thank you so, so much. I’m already thinking about new topics to have you back for. Your manner of delivery and the way you break things down for us to understand them is really special. Thank you.
Emiliano: Well, I appreciate that. Thank you.
Elliot: Where can we find you online?
Emiliano: I am pretty old.
Elliot: Does this mean AOL?
Emiliano: So, let me give you my MySpace address. I have a very minimal social media footprint. It’s on Facebook. It’s basically my name and my degree, Emiliano Chavira, MD, MPH, FACOG on Facebook.
Elliot: Beautiful. MD, FACOG, is there something after that?
Emiliano: The in-between was the MPH, Master Public Health.
Elliot: Oh, Master Public Health. M-D, M-P-H, F-A-C-O-G.
Elliot: I guess that wasn’t taken. “Emiliano Chavira, MD, MPH, FACOG.”
Elliot: All right, Doc. Thanks so much. You can always find us online at informedpregnancy.com or on Instagram, @doctorberlin. D-O-C-T-O-R-B-E-R-L-I-N.