“Antepartum Fetal Testing, Part One: Introduction and Fetal Kick Counts” – with Kelly Zafman, MD

Dr. Kelly Zafman joins Dr. Fox to discuss her research on antepartum fetal testing. In part one, they discuss how antepartum testing helps determine the risk of stillbirth and kick counts, or tracking a baby’s movement to gauge the health of the pregnancy.

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Dr. Fox: Welcome to today’s episode of “Healthful Woman,” a podcast designed to explore topics and women’s health at all stages of life. I’m your host, Dr. Nathan Fox, an OB-GYN and maternal-fetal medicine specialist practicing in New York City. In “Healthful Woman,” I speak with leaders in the field to help you learn more about women’s health, pregnancy, and wellness. All right, Dr. Kelly Zafman, welcome to the podcast. I am so happy to have you on as a guest.
How’s life?
Dr. Zafman: It’s good. Thank you so much for having me. I’m so excited to spend some time talking with you.
Dr. Fox: So, Kelly, as you know, you are a third-year resident and OB-GYN at the University of Pennsylvania or as we say, Penn.
Dr. Zafman: Yeah, coming to you from Philadelphia today.
D. Fox: How’s residency going by you?
Dr. Zafman: It’s great. I am a third-year which is crazy. It’s hard to imagine that so much time has passed since I was a medical student sitting in your office for a year. But it’s been really good, such incredible learning. And, you know, the days are long, but the years are definitely short. So, I can’t believe I’m already at 30.
Dr. Fox: For our listeners, Kelly spent basically a year in medical school, took a year off, and did research with us. One of our prior guests on the podcast, Mackenzie, was on and was a sensation did the same thing the year after you, but you basically paved the way for this. And you took our office by storm. We didn’t know what to do with you. Kelly shows up and we figured it was just some student, you know, sitting around, like, looking at the walls and, you know, wandering about, and you become, like, the most prolific student publisher, like, in the history of the world. It was unbelievable. How did you do that?
Dr. Zafman: I mean, I think a lot of it comes with excellent mentorship. So I’ve been lucky.
Dr. Fox: Love it. Good work. All right.
Dr. Zafman: But, you know, really, I think that, you know, having that experience of being able to, first of all, sit in an office, where we have such amazing providers taking care of patients that are always thinking of questions and coming up with things that, you know, their patients wanna know, that we don’t really have data about. And I think that was kind of the exciting thing was to be able to kind of sit there and kind of soak in sort of everything that was going on clinically and then work with you to think of questions that we thought would be really useful to our patients and to other OB-GYNs that are taking care of patients. So, it was a really awesome year. And I had so much fun working with you and I missed the office.
Dr: Fox: Well, we missed you too. It’s funny, just the other day…literally like two days ago, my wife and I were at something and someone was telling us about an event that’s gonna happen, and it was in June. And so I pulled up my calendar on my phone and I click on June 21st, and my wife goes, “What the hell is Kelly day?” I said, “Oh, no, June 21st is Kelly day. That’s the day we celebrate, you know, Kelly as being a part of our office. It was June 21st. And every year, there’s an anniversary of it for Kelly day. There’s a McKenzie day also. And yeah, she’s like, “Well, that’s a little weird, isn’t it?” I was like, “No, it’s not weird at all. It’s totally normal to have Kelly day on your calendar, June 21. We’re gonna make it a national holiday.”
Dr. Zafman: Perfect.
Dr. Fox: Yeah, but that’s in honor of you. But seriously. I mean, what you accomplished at that short time in one year was quite remarkable. I mean, really…
Dr. Zafman: Oh, thank you.
D. Fox: …you did more research, and wrote more, and published more than probably most people, even those who are engaged in some form of research, publishing, maybe their entire careers, but certainly during their training and fellowship, and you did it all as a student. And so I’m very proud.
Dr. Zafman: Well, thank you.
Dr. Fox: One of the papers that you were the first author on, I’m gonna call it a landmark paper, from 2018 was looking at one of the kinds of antepartum testing. And that’s what we’re talking about today, just the whole topic of antepartum testing. But that’s why you have, you know, the chops to actually talk about this because your published research around this topic.
Dr. Zafman: Yeah, thank you. I’m excited to talk about it. I think this is a really important topic for women during their prenatal care. And we’ll get into a little bit sort about what we found in our paper together.
Dr. Fox: Exactly. So, let’s just take an overview. We’re talking about sort of…the formal term for this might be called antepartum testing or antepartum fetal assessment, but what are we talking about here? Like, how would you explain that in sort of, you know, human terms?
Dr. Zafman: What we’re basically trying to do to kind of rewind to the purpose of doing this testing, and then we’ll go into different types of testing, and when we do it and how, is really to prevent stillbirth. Fortunately, stillbirth is a rare outcome. Overall, in all pregnancies over 20 weeks, the rate of stillbirth is about 6 in 1000. And then if you take women who are full-term, so over 37 weeks, the risk is about 0.2 in 1,000. So, fortunately very rare outcomes, but obviously for women that have this outcome, it’s devastating. So, if anyone has had a stillbirth or knows someone with stillbirth, obviously, it’s, you know, the most horrifying thing that can happen to a pregnant person. And so, our goal with antepartum testing is to prevent stillbirth. And we don’t know how babies are doing in there. And so really what we’re trying to do is to find those babies that show the signs that they are in distress and not receiving adequate oxygen, and then we sort of have strategies that we use, whether it’s delivering or repeating tests or doing more monitoring, to figure out who needs to be delivered and when. And that’s kind of the overarching purpose of doing antepartum testing.
Dr. Fox: Yeah, I think…that was great, and I think there’s a lot to unpack there. And the first is that, again, the reason we do this is essentially to predict which babies are not doing so well and might be at an increased risk of death or neurologic injury. And so, we can intervene before that happens, so ideally, it’s gonna prevent stillbirth or injury. But what you said before about lack of oxygen is really key because we’re not necessarily testing, sort of, is the baby healthy from, like, a genetic standpoint or from an atomic standpoint or a metabolic. It’s really, is the baby getting enough nutrients, and oxygen, and water from the placenta? So it’s really more a test of the placenta than the baby. Obviously, if the placenta is not working well it can affect the baby. But we’re really trying to figure out a specific cause of stillbirth, which is the placenta shutting down, meaning a test like this is not really going to predict or prevent stillbirth from some other reasons, potentially. It’s really directed at those that are caused by a placenta that’s not working so well.
Dr. Zafman: Yeah, exactly. And a lot of the parts of the testing itself is sort of looking at signs of the placenta working well. And we’ll sort of talk about what those are. But yeah, exactly, you know, it can’t predict all of the causes of stillbirth, but really focused on sort of the causes that could be related to the placenta not providing as much nutrients to the baby.
Dr. Fox: Yeah, and I think that’s important clinically for a number of reasons. First, is that when we’re doing these tests, a reassuring test, a normal test, even if it were 100% true about the placenta, let’s assume nothing’s 100%, but even if it were 100% true about the placenta, it does not mean that there’s a 0% chance of stillbirth because there’s stillbirth from other reasons that have nothing to do with the placenta, right? You couldn’t predict that three days from now, the baby would roll over on his or her cord and block the umbilical cord, you know, for 15 minutes, which is a fluke thing that can happen, which is a horrible thing. You wouldn’t be able to predict that because it’s just sort of random. It’s like getting hit by a bus. You can’t predict that. And that’s one reason it’s important.
And the second thing is there are certain conditions, which have an increased risk of stillbirth that’s not related to the placenta. And so, the intervention that we need to do to prevent stillbirth is not related to these testing, but more delivering early. Like a classic example is cholestasis, which we did a podcast on before, where it’s not a problem with the placenta. And so, yeah, we can test the baby and say the placenta looks fine, the baby looks fine, but that’s not really gonna have any relevance to cholestasis. The real way to prevent the stillbirth is deliver it before it happens, so we deliver early. And that’s why something like cholestasis, we’re inclined to deliver earlier, like 37 weeks at 36 weeks because we have no way of reassuring us that the baby’s not gonna have a stillbirth, but something like diabetes or high blood pressure where the stillbirth is related to the placenta, if the testing is normal, we feel comfortable pushing pretty much all the way to the due date almost because we have reassurance that is useful to us.
Dr. Zafman: Yeah, exactly. And unfortunately, I feel like because we have no way of reassuring ourselves besides this testing, sometimes we end up testing people even though we don’t really think that that pathway is related to the placenta, like things like cholestasis.
Dr. Fox: It’s nice to have a test that says your baby looks great. It’s a nice thing to have, like to get that sort of scorecard. And again, just to review, the things that the placenta is gonna provide for the baby that we’re testing for is on the sort of most basic level, food, right? And that’s gonna have the see how the baby’s growing. So some of the tests are involved in, how’s the baby growing? Because the baby’s growing, the baby’s getting food. The second would be water, right? Is the baby sort of drinking? The baby drinks through the placenta. And so, a lot of the things that we check are, is the baby getting enough water through the placenta? And the third is oxygen. And, you know, so is the brain functioning well? Because if you don’t have good oxygen, you’re not gonna sort of function so well. And so those are the three things we really look for in these tests. And we’ll talk about the specific tests how they do that. So let me ask you a question, does it work? Right? To people who get antepartum testing, do we reduce the risk of stillbirth?
Dr. Zafman: Yes, that’s a good question.
Dr. Fox: Thank you.
Dr. Zafman: So we do… Yeah. It’s a tricky one to answer, but I think overall we think that we do. And the problem, of course, is that, you know, when we have a test that comes back positive, meaning the baby shows the signs of not getting adequate nutrients through the placenta, that we recommend, you know, depending on the gestational age, delivering at that point. And of course, the problem is that when we deliver, we don’t really know if the baby comes out kicking and screaming, if, you know, the problem was that the test was a false positive, meaning that the baby would have been fine and we didn’t need to deliver, or, you know, was it actually that, you know, had we continued the pregnancy and not deliver the baby at that moment that a week later something catastrophic would have happened? So, I think that’s a little bit of the tricky part. And then the other thing is to say a lot of these, you know, stillbirth is a rare outcome still, so it requires a lot of women to study in order to tell us, you know, whether we reduced the risk of stillbirth. And a lot of the times we’re looking specifically at people who are increased risk of stillbirth. That’s why we’re doing this testing. So overall, we do think that we do reduce the risk of stillbirth, but the data I think is a little bit tricky in those ways.
Dr. Fox: Yeah, I mean, the only way to know for sure is to somehow sign up like 10,000 women and say, “All right, we’re gonna randomly do this testing on half of you and not do it on the other half, and see what happens to your babies.” And you would have to do it on women at risk for stillbirth, right. So, you’re gonna take 10,000 women with high blood pressure and diabetes and twins and this or that, and who’s gonna sign up for that, where they’re like, “Oh, my baby’s not getting tested, excuse me?” And so, it’s never really been done. And since it’s never been done, we can’t say for certain whether it reduces the risk or by how much it reduces the risk, and also, what exactly are the right indications for it? And that’s why you’ll see a lot of disagreement around, you know, from center to center, from city to city, from country to country, who gets this testing? When do you start? How often do you do it? Which ones you do? Because it’s really based on just…a lot of it is opinion, experience, availability, cost, you know, logistics, and not so much that we know that test A is the right thing to do for condition A. We just don’t know that with any great level of certainty. So, we’re just sort of, you know, doing what we think is right. And different people feel differently about this. So, you’ll see a lot of differences.
Dr. Zafman: Yeah. And I think it’s interesting, you know, a lot of this comes up in obstetrics that, like, we only know what we, you know, know, based on people’s experience and the data that we do have, but it’s hard to, you know, do full randomized controlled trials to really get, like, the true answer to these things, even though these tests were designed in the 1980s, so they’ve been around for a long time.
Dr. Fox: Yeah, they’ve been around for a long time. Some of us were alive in the ’80s, Kelly.
Dr. Zafman: Some not.
Dr. Fox: Way back in the 1980s when the world was black and white. Who might be recommended to get this kind of testing? Like, women with what sort of either pre-existing conditions or pregnancy-related conditions? And again, this list won’t be exhaustive because there’s certain situations where it may come up, or we’re not gonna list. But what are the more common ones that are indications for this kind of testing?
Dr. Zafman: Yeah. So, a lot of times we’re thinking about women that we think could be at increased risk of stillbirth, and they’re lots of different indications, but some of the ones that come up more frequently are things like diabetes, so having type 1 or type 2 diabetes, or having gestational diabetes that requires insulin during the pregnancy. Many women will get testing, having hypertensive disorder, so having either high blood pressure outside of pregnancy or high blood pressure that develops in pregnancy, like gestational hypertension, having autoimmune conditions, things like lupus, having thyroid conditions that are sometimes not well-controlled can increase your risk of stillbirth, having things like antiphospholipid antibody syndrome, which is like a clotting disorder. And sometimes that’s something that’s discovered if women have things like recurrent pregnancy loss or have clots that they’ve developed either during or outside of pregnancy. And then other things that we think of are if a woman’s pregnancy is postdate. So, being over 41 weeks, people’s risk of stillbirth starts to increase a little bit. So, if women want to continue the pregnancy, oftentimes, we’ll recommend that they do testing. And then having a history of a stillbirth we know is associated with an increased risk of stillbirth in the next pregnancy. So, those women are also often recommended testing.
Dr. Fox: Yeah, I think those are women who typically are gonna know from the very beginning of pregnancy that they’re gonna have some intense monitoring, except for those who go past 41 weeks because you can’t really know that. But then there’s also things that sort of come up during pregnancy and what started as “low-risk” pregnancy, things like, we’re concerned about how the baby’s growing, like fetal growth restriction, or maybe we’re concerned about the fluid, or maybe a very common reason is the mom’s pregnancy is going great, but for whatever reason, she doesn’t feel the baby moving as well. And she’s concerned and we’re concerned that maybe something has happened, and there is a problem. And so this is the same kind of testing we’re gonna do to reassure her that the baby is moving well, and is okay. And again, there’s also other reasons, it’s individualized. And like we said, exactly which test to do and when you start is gonna vary from place to place. But what are the tests available to us that we can use? And I think let’s start with the most simple ones and work our way to the most complex ones. I think the most simple one is probably just what we call either fetal kick counts, or movement counts, or something like that. How do you describe that to people?
Dr. Zafman: Kickcount is something that we often talk to women about in their pregnancy when they’re kind of in the third trimester. And that’s really just a woman keeping track of how often a baby is moving. And lots of times women will kind of know the pattern of their baby moving. People will say, “Oh, my baby’s more active at night or during the day.” And really, what you wanna do is see any, you know, differences. So, if all of a sudden you feel like, “Oh, the baby is not moving as well today,” that’s definitely something that should raise some red flags. And then if a woman feels like a baby’s not moving, we recommend doing kick counts, which is basically having someone really keep track of the number of movements that they’re getting. And generally, we say that in two hours, you should be getting 10 kicks. And that’s, you know, a good sign that the baby’s doing well. But if that is persistent where you’re not getting the 10 chicks in two hours, or if the movement really feels like it’s off, that is usually a reason why we recommend that a woman comes in for one of our sort of methods that we use for antenatal testing, which we’ll get into. But interestingly, I think the fact that, you know, kick count is obviously a very low-tech kind of way of us to keep track of the baby, very easy for women to at home. If women aren’t getting good movements, that does increase the risk of stillbirth. So that’s something that should definitely, you know, we counsel patients about it, it’s important for women to keep track of at home, especially if they have one of those risk factors that we talked about.
Dr. Fox: Yeah, I think this is one of the tough ones because we always talk to women about, you know, fetal movements. And it’s kind of vague, because number one, every baby does move differently, right? Babies behave differently inside and outside. Some babies are more active, some babies are less active. And that’s not necessarily an issue related to their health. It’s just related to their sort of, let’s say, personality or whatever it is. And also women’s perception of movement changes from pregnancy to pregnancy, from woman to woman. Some of it’s related to her sort of body composition. Some of its related to where the placenta is. Some of it’s just related to how busy is she during the day versus, you know, just hanging out not doing as much and you have more time to focus on the kicks. And so, there’s a lot of variation. And, you know, 99 times out of 100, when someone doesn’t feel the baby moving so well, everything’s fine, either on follow up instructions, like, “Okay, the baby doesn’t seem to be moving so great, why don’t you lie down, and close your eyes, and focus on the baby, and count the kicks?” And if it’s, you know, a certain amount in a certain amount of minutes, everything’s okay or if she comes in for formal testing, everything’s fine. But 1 out of 100 times, it’s not okay. So we have to take it seriously. And I think a lot of people…this causes a lot of angst for pregnant women, I would say. It’s a tough balance between trying to, you know, encourage women to assess how their baby’s moving but not freak them out every day if there’s any change. How do you sort of balance that? Because that’s really tough. I mean, you know, I’m in this a few more years than you and I still find it difficult.
Dr. Zafman: Yeah, I mean, I think it is really tough because on one hand, you don’t want to have women, you know, rush in every day, you know, and be freaking out at home that, you know, things aren’t going well with the baby, but at the same time, like you said, you know, if 1 time out of 100, you find something wrong, you know, it also is scary. So I think, you know, as everything, it’s really like a joint decision-making conversation with the patient. I think a lot of it is, you know, educating them and, you know, talking to them about, sort of, you know, kind of the different thresholds that they should have to come in. But yeah, I think it can be really distracting. And I think for women who have, you know, consistently been feeling decreased movement, even though they’ve had great tests, sometimes that’s a reason like you said that we can put people in testing to give them and ourselves kind of reassurance about how the baby’s doing. That can be one strategy for someone that’s really worried and feels like the movement really has, you know, been decreased for long periods of time, even though they’ve been looking great on sort of the test that they do when they come in.
Dr. Fox: Yeah. When I do my practice, I don’t generally have women, even those at increased risk, do formal testing, like kick counts every day. Usually, if I’m concerned enough, I have them do formal testing in our office, you know, once a week or twice a week, whatever it is. But I do tell women after a certain point in pregnancy and it’s different for everybody, but let’s say 24 weeks or so, you should feel your baby move every day. Like, that’s number one. Like, you shouldn’t go a full day without your baby moving. And number two, you know your baby better than anyone else. So you know what’s normal, like you said, “My baby moves at night. My baby move during the day. My baby moves after I eat. My baby moves when I’m hungry.” Like, everyone’s a little bit different. And if your baby’s behaving normally, then things should be okay. But if you notice a change and decrease, right, from what is typical, I say at that point, that’s a pretty good time to, all right, let’s do something a little bit more formal at home, lie down, close your eyes, just focus on the movements. If you know that eating or drinking suddenly gets your baby to move, you could try that, but just focus on the movements. I usually tell them, if you feel three movements within 30 minutes, everything’s okay, 10 movements in two hours. There’s a lot of ways to do this. And then I say, “But if you really think the baby’s not moving normally, and you do this, and the baby does not move three times in a half-hour, yeah, come on in.” And I say, “Probably it’s fine but let’s just be 100% sure.” And that’s sort of the way I do it in my own practice, but again, there’s a lot of variation with this. Some people have their patients do kick counts every day. Some people have never do it. Do you recommend doing it routinely?
Dr. Zafman: No, I don’t think routinely, I think you know, for women that were really worried about, like, let’s say they have a really small baby, those are kind of some of the babies that we worry about more. I think that, you know, kind of talking about, you know, they should have a little bit of a lower threshold to come in, you know, if they’re not feeling good, feel movement, and they’re not getting those kicks, that should really prompt them to come in. But I think for the average kind of risk pregnancy, it’s, you know, very reasonable to just have people pay attention. And if, you know, they’re worried, they should just come in.
Dr. Fox: Yeah, I think that doesn’t make sense. You know, if something is new that’s going on, you know, her blood pressure’s newly elevated or, like you said, the baby’s not growing well, definitely, there’s reason to have some heightened awareness of this, because even if we’re seeing them once or twice a week, it’s reassuring to a high degree, but maybe not 100%. So, that’s a situation where people probably need to be on, you know, increased awareness, heightened alert, whatever it is. But in the routine setting, again, I think it’s important to have a sense of fetal movements, but I think that, you know, the last thing we also wanna do is just drive people crazy. You know, we as doctors have a great capacity to drive people crazy. It’s one of the things they teach us in medical school right away. It’s like, first, how do you drive people crazy and make them totally afraid of everything in the world? And we’re good at that. I mean, you know, we did that with Corona. We’re really good at that. That’s our real talent.
Dr. Zafman: Yeah, absolutely. And, you know, we ask a lot of our patients, you know, we’ll get in some of the testing, but having people come in once or twice a week, in addition to all of their prenatal visits, we ask a lot of people, so I think putting more on people’s plate and more worries, you wanna do it when we think it’s really necessary.
Dr. Fox: Yeah, no, I think that all makes a tremendous amount of sense. Wow, Kelly, thanks. That was a really great introduction to fetal testing, as well as kickcounts. And what we’re gonna do is we’re gonna pick it up next week, and talk about the specific tests that we do, nonstress tests, biophysical profiles, and more. Stay tuned everyone for next week’s podcast for part 2 with Kelly Zafman.
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