The role of height for your baby’s health


Augusta, Ga. (WJBF) – Low birth weight and future health: what does the weight and length of a baby indicate going forward with that child’s health? There is exciting new research being done at the Medical College of Georgia, and neonatologist Dr. Brian Stansfield answers many questions on the subject on The Means Report to give parents a whole new perspective on their young ones.

Brad Means: Until now, a big thing that we’ve depended on is the child’s weight when he or she is born. What kind of indications does that give us? Now we’re factoring in the length of the child as well and what that might tell us as to that child’s future. And leading the way on that front is Dr. Brian Stansfield. He’s a neonatologist at the Medical College of Georgia and the Children’s Hospital of Georgia at Augusta University. Dr. Stansfield, thank you for what you do for our children. We appreciate you.

Dr. Brian Stansfield: Thanks, thanks a lot.

Brad Means: Absolutely, and thank you for this research. It can be found in the Journal of Early Human Development. It’s getting a lot of play on the national scene right now. I really did think how much a child weighs was pretty much all you need. What made you start caring about how long the child was?

Dr. Brian Stansfield: Well, it’s funny. We’ve, I think as a community of pediatricians, we’ve long had an interest in total growth, both length, head circumference, weight, understanding how all those metrics contribute to early life health. And it’s only been in the last 30 years or so that we’ve understood at all that early life development matters for the whole life span. And it started with David Barker, an epidemiologist in Great Britain who identified that survivors of the early famines in Great Britain went on to have higher incidence of cardiovascular death. And so, they started to ask questions. Well, what is it about the survivors of famines that beget higher risk for cardiovascular mortality? What they identified was that birth weight became a very good marker, that was a surrogate marker for this mortality index. So over the last 30 years, we’ve started to piece into that a little bit more, to understand. Was it birth weight? Is it the growth afterwards? Is it what happens while they’re in the womb? Is it what happens afterwards? Is it certain factors during all this time that matter, that beget this risk? I think over time, we’ve realized that it’s very complex question. Part of what we’re interested in is, how can we better understand it? How can we identify an at-risk patient population, going forward?

Brad Means: And so, is that when we started to look at this Ponderal Index, this a combination of height and weight?

Dr. Brian Stansfield: Yeah, that’s correct. So we’ve long known that birth weight was a really good marker. If you are a big mother and father, you tend to beget big babies, big offspring. And vice-versa is true as well. Where we started to identify a risk was in mothers and fathers who should constitutionally have a larger infant. And they were having smaller infants, whether it’s because of poor nutrition status or diabetes during pregnancy or high blood pressure during pregnancy, any of these things that might affect how blood flow to the placenta. And therefore nutrition to the baby might be altered, apart from what we’d consider to be healthy pregnancy. So these babies who tended to be or constitutionally would be a normal birth weight or even a large baby, when they’re born small, those are the babies that we identified were at risk. Now the problem was that birth weight is one of the first things affected when blood flow or nutrition to the baby is altered. They tend to start to reduce their weight, more so than they reduce their length. You can get this snapshot, based on birth weight. But you really don’t know what the trajectory is. So is that a constitutional birth weight, meaning are they just arriving at what they would’ve been at all along? Or are they actually affected by what’s going on in utero?

Brad Means: But the same goes with length, doesn’t it? You’re both looking at a single point in time.

Dr. Brian Stansfield: It does; it does. But length is a slower affected growth modality. Birth weight is much more quickly affected. So for instance, if you developed high blood pressure late in your pregnancy, your baby’s weight may drop off somewhat, but the length still tends to be preserved. And so, we can index birth weight to length, a metric in birth weight that’s affected pretty quickly to a metric like length that’s slowly affected over time. And we can get a sense of, well, is this low birth weight that’s proportional to their length, or is this low birth weight that’s disproportional to their length?

Brad Means: In a perfect world, do we want that weight and that length to increase in sync–

Dr. Brian Stansfield: That’s right.

Brad Means: as the child grows? Is that what we want?

Dr. Brian Stansfield: That’s right. If you look at the last trimester, weight and length gains are pretty linear, meaning for every day that you’re in the womb, you gain a certain amount of weight and length. But over time, if you have this placental insufficiency where the placenta itself is not getting enough blood flow or the mom has an illness, whatever that may be, the blood flow or the lack of nutrition to the fetus will more often affect the growth, the weight gain, than it will the length.

Brad Means: So are you trying to get the mom to treat herself better while she’s carrying that baby? Or are you trying to get parents to raise their child in a better environment?

Dr. Brian Stansfield: So I think it’s both, right? So we obviously want. Healthy babies, for us, start with healthy mothers. So we’re very impassioned about trying to make sure moms take care of themselves, that they avoid smoking, which is big risk factor for having low birth weight or poor growth in utero to begin with. But a lot of these things happen just because moms are at risk, whether it’s because of race or family history or just previous medical conditions. So pregnant moms, pregnancy tends to exacerbate health conditions. So if we can go into pregnancy healthy and then, try to encourage healthy pregnancies, then that’s at least the first step. Then to answer the second part of your question, we are very interested in identifying who’s at risk. Once you’re born, you’re born. All those risk factors are present. So can we identify patients that may go on to have a higher risk or obesity or cardiovascular disease and therefore, screen them a little bit more closely? And vice-versa, can we identify patients that are at low risk and maybe relax some of the screening recommendations?

Brad Means: All right, so you found a bunch of kids that were on their way to growin’ up–

Dr. Brian Stansfield: Yeah, yeah.

Brad Means: 379 adolescents taking part in your study. You got some information from mom and dad about what they were like as babies. What’d you find out about the way they were turning out?

Dr. Brian Stansfield: So it’s interesting. We had used this database quite a bit to understand how they might go on to develop obesity. And in this most recent study, we’ve turned our attention to looking at heart development and how that occurs. Just to preface this, we had looked at an animal model and had simulated this poor in utero growth in an animal model and showed that a lot of the effects on the heart are permanent, meaning the adult animals showed some of the same evidence of poor heart growth that the young animals did. So whatever happened in utero seemed to really beget this lifelong impact on heart development. We turned our attention to humans and trying to understand okay, well, does this mirror what we’ve seen in animals? And in fact, it seems to. When we looked at birth weight alone, we didn’t really see correlations between birth weight and a marker of future heart failure which is left ventricular mass indexed to body weight and body surface area. When we looked at birth weight alone, we didn’t see any correlation. But when we added in these length metrics to proportionate out birth weight, we saw that there were, in fact, uncovered associations between birth weight for length as noted by Ponderal Index or BMI and left ventricular mass.

Brad Means: Who’s gonna have the better heart, the long baby or the short baby?

Dr. Brian Stansfield: Yeah, the long baby for sure. And that’s because when you look at weight over length, if the denominator of that metric increases, you’re gonna do better as far as BMI.

Brad Means: But we can’t control fetal growth. Or can we? Can we influence it?

Dr. Brian Stansfield: So we can influence it by, first thing is probably stopping smoking. So if you’re a current smoker and you’re thinking about getting pregnant or you’re of fertile age, then we certainly would discourage smoking. And if you find that you’re pregnant, we would certainly discourage smoking. And a lot of women do. That’s a nidus for them to stop smoking and not just themselves smoking, which is important, but also being around cigarette smoke itself. So that’s probably the first thing. The second thing is taking care of themselves, so continuing to obtain proper exercise, having a well-balanced diet. I mean, the things that we hear about overall health are just more emphasized in pregnancy.

Brad Means: So if a mom does make these lifestyle choices and changes and the baby, let’s say, is genetically predisposed to have problems, can mom’s choices kinda maybe beat that system?

Dr. Brian Stansfield: We think it can. We think that the environment and the inheritability of any of these, like cardiovascular disease and obesity, can be modified. So you can’t just give up. Because there’s a family history of obesity or cardiovascular disease doesn’t mean that you can’t change that. And I think that’s what we’re finding over time is that the environment does play an impactful role. Neither one operates independently of the other and that both can be modified.

Brad Means: Any message, at this point in your research, to pediatricians when they get a hold of those families?

Dr. Brian Stansfield: So my big message is mostly to adult physicians. Because I think when you show up at 35 or 40 and you’re starting to develop coronary artery disease or you’ve had your first heart attack in your 50s, that we start to think about what may have happened 30, 40, 50 years ago as a possible influencer of those outcomes. And so, can we start when these patients show up healthy in your routine followup clinic? Can we start to look at birth weight and say or birth BMI and say, “You know, you’re a little bit “higher risk, just based on this one risk factor. “Maybe we should really emphasize more regular screening.” Or, “Can we maybe relax some of that screening “because you seem to have one protective risk factor?”

Brad Means: I bet the parents in your study were grateful to you because now they can raise their children differently if they weren’t already more closely monitoring them, right?

Dr. Brian Stansfield: Well, I think information breeds power. So if we can inform our parents that you’re already at a little bit higher risk, so let’s maybe emphasize diet and exercise a little bit more. Or hey, you’re protected, but that doesn’t mean you have a license to just eat and do what you want. You need to continue these healthy trends.

Brad Means: The Ponderal Index.

Dr. Brian Stansfield: Ponderal Index, that’s right. Dr. Stansfield, thanks for your research. It is fascinating. It’s tough to cram it into 12 minutes. But I think you did a great job, and I appreciate you.

Brad Means: Well, thanks for the opportunity, Brad.

Dr. Brian Stansfield: Absolutely, you’re always welcome. Read more about it in the Journal of Early Human Development. Dr. Brian Stansfield, great work at MCG and the Children’s Hospital of Georgia at AU.

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Brad Means

The Means Report first aired in January of 2009 offering coverage that you cannot get from a daily newscast. Forget about quick soundbytes -- we deliver an in-depth perspective on the biggest stories. If they are making news on the local or national level, you will find them on the set of The Means Report. Hosted by WJBF NewsChannel 6 anchor, Brad Means, The Means Report covers the topics impacting your life, your town, your state, and your future.