New Fetal Monitor -- In-Depth Doctor's Interview

Ivanhoe Broadcast News Transcript with
Lawrence DeVoe, M.D., Maternal Fetal Medicine Specialist,
Medical College of Georgia, Augusta, Georgia,
TOPIC: New Fetal Monitor

What's the traditional method of monitoring a baby during delivery?

Dr. DeVoe: For about the past three-and-a-half decades, fetal monitoring has been done in the United States using one of two approaches, either the time-honored traditional approach of using the stethoscope and listening to the baby intermittently during labor or, probably more frequently in the last quarter of a century, using an electronic monitor placed on the woman's abdomen or inserted through the vagina to monitor the baby's heart rate and also uterine activity. And today in the United States, somewhere between 80 percent and 85 percent of labors are monitored using electronic devices.

What kind of improvement is the new Stan System?

Dr. DeVoe: Well, the monitors that we have used for approximately three decades pick up fetal heart signals, and those signals then get translated into a continuous printout of fetal heart rate. Those that are educated in the interpretation of fetal heart rate can recognize certain heart rate patterns or pictures that create a sense of how the baby is doing. And there are patterns that are associated with healthy babies and patterns that are associated with babies that are getting into difficulty. At either extreme, it's pretty easy to tell a baby that's very healthy and doing well and a baby that is very sick and needs to be immediately delivered. That's a very less-common situation. In between, there are a lot of babies in whom the monitoring patterns create a sense of uncertainty about the condition of the baby. And so the person who's watching those monitors, even a trained individual, may not be sure that this labor should continue or this baby should be delivered. But very often what'll happen is because of that uncertainty there will be an intervention, either cesarean delivery or maybe putting on forceps or a vacuum if the patient's in the second stage of labor and delivering a baby who's heart rate tracing didn't look so normal but who's perfectly healthy and probably could have delivered normally if given enough time.

How does the Stan System work? Is there anything you can compare it to?

Dr. DeVoe: Let me tell you what the new monitoring system has, because looking at heart rate patterns alone, we recognize that there are heart rate patterns that are confusing and create problems because you can't really be sure what's going on. This monitoring system actually takes the fetal heart rate and extracts from it the electrocardiographic (ECG) signal. If you look at fetal heart rate patterns, they are hundreds and thousands of these little signals that are all plotted together. So this takes these signals and then gives you an analysis of the fetal electrocardiogram.

I will give you an analogy from adult medicine so you can see how this translates into what goes on in the uterus. In adult medicine, if you want to find out how a heart is doing, we can put an adult on a treadmill, place electrodes on that person's chest, and then have them start to exercise and look what happens to their electrocardiogram. And there are certain changes in the electrocardiogram that a cardiologist would recognize as a heart that wasn't getting enough oxygen. Well, we can't quite do that with the baby. It would be difficult to take the baby out, put them on a treadmill and then bring them back in. But what we can do is we can look at the baby's cardiogram and look for some of the same kinds of changes that would tell us either the heart is getting enough oxygen or it's not. And this is one step removed from the critical concern of how much oxygen is getting to the baby's brain. The heart is kind of the gatekeeper of all of that, and if the heart's getting enough oxygen, we can be reassured that the brain is getting enough oxygen. And in looking at this, we can then add this information to the standard fetal heart rate monitor tracing and say this baby who's heart rate tracing may not look so normal or reassuring has a normal appearing cardiogram and, therefore, is good to continue to be in labor. Conversely, we can also get an early warning and a tracing that may not be so reassuring that this baby really does need to come out and we can avoid having a baby that's gonna get into problems.

In the studies that have been done thus far, what has been shown?

Dr. DeVoe: There have been a lot of studies that have been done, and probably if you look at the study of fetal heart rate monitoring systems, this system has been one of the most rigorously studied systems that's appeared anywhere in the world. And what the largest studies have shown is that the use of this system with the additional heart rate information from the fetal electrocardiogram does two things. Number one, it helps you deliver better babies. It prevents a condition called fetal acidemia, which is a step toward getting damage to the baby. It reduces the likelihood that that's going to happen. And by the same token, it also reduces the need for operative intervention. So it's really kind of the best of both worlds.

Is it one of the biggest things that you've seen in your field?

Dr. DeVoe: Well I first touched a fetal monitor in 1968. So if we do the math, that was 37 years ago. Of course it didn't look like the machines we have now.  And we thought it was going to be the most wonderful thing because we would be able to look at these monitor patterns and know what was going on with the baby and be able to predict the future and to get good outcomes. As time went on, that didn't come to pass. Most of the studies using traditional monitors show that they didn't really deliver on that promise of preventing injury or in fact the opposite, the injury was almost as common with the standard monitor just listening with the stethoscope alone. But the monitor did create the performance of more cesarean and operative deliveries. So you had and that may be the worst of both possible worlds rather than the best. There is little doubt in my mind that this additional information, which has been extremely well studied, gives you a much better perspective and gives you one step closer to what you're really interested in. Is the baby's heart getting enough oxygen? And if that's the case, we can continue to labor and deliver normally. And if not, we'll get an early warning sign that baby needs to come out. And I think, in my experience, which is only 37 years, that this is one of the most significant events and developments in infant partum care that I have ever seen.

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END OF INTERVIEW

This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc., or any medical professional interviewed. Ivanhoe Broadcast News, Inc., assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors in different ways; always consult your physician on medical matters.

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Toni Baker
Director of Media Relations
Medical College of Georgia
Division of External Affairs
Alumni Center, Fl-1046
Augusta, GA 30912-7790
(706) 721-4421
tbaker@mcg.edu