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Video transcript

I'm here with dr. Laura Bacharach at Stanford Medical School and what we're going to talk about we're going to talk about normal and abnormal growth in children fascinating so this is an important concern parents really worry if their child is growing normally and physicians worry about this too because the change in height is an important barometer of how the child is doing overall in terms of health all right so to begin to assess the child's growth pattern we have to think about what are the determinants of where the child should be on the growth curve right the number one most important determinant of course is genetics short parents more likely to have short children and vice versa and that's true even so even when a child is young if like big because sometimes I've seen the opposite so you know people who are petite have have large children and all the rest but it is true that even if someone is large or someone is large they're more like and have large children even even in infants and toddlers you've hit upon important a really important issue that's shown here in this slide the size of a baby at birth isn't necessarily going to reflect the genetics there are babies that are born small because mother didn't have prenatal care mother was a smoker or other factors that compromised the growth of the child and those babies can be born small for their gestational age during the first two to three years of life they have a chance to catch up on the curve and reach what's called their genetic potential so let's let's just make sure so the Allens will make sure I've seen these curves before when I went to visit a pediatrician even I remember this one I used to visit the nutrition which I did maybe a little too long but uh so this is so this is this axis right over here is age in months in months so this is right here birth right this is birth right so if a baby is born at I don't know this is the weight right over here so if a baby is born at five pounds it's this is in pounds this is kilograms okay so five pounds is right over let's a low is that right does 6 CF 5 pounds would be right over here so this would be a baby born at five pounds right and I'm talking more here during this growth lecture about the height or length of the baby okay throughout babyhood and in childhood but let's say the baby were born lighting weight and short in length so maybe 18 inches right here right would be a short length and let's say that that baby was small because his mother had issues during the pregnancy is it always the case that the baby will be small because of issues or I mean know if the bottom line is that genetics plays less of a part in the size of the baby at birth I'm still later on in childhood my mixes so to come back to your point um you will meet parents whose babies seem to be larger or smaller than they are right but by age 3 the child should be hold on one second let me just close this okay by age three the child should be in his or her genetic group if you will I see so there can be movement on the growth curve in the first two to three years of life there can be catch-up growth where the child who was small let's say moves from below the curve up to the 50th percentile so each 24 months so this would be a child who does something like this exact right exactly um and you can have the converse well you have a very big baby let's say mother had uncontrolled diabetes and the baby was born very large that baby can have catch down growth right 50th percentile right by the age of three certainly movement across percent house is considered to be abnormal huh and warrants and Eva's investigation so you really can predict someone's even adult height based on where they are at three a general rule of thumb is that by age two and a half to three the child is in their genetic group really oh wow well I didn't realize that that quickly you can kind of so if a child at age three or four is in the twenty-fifth percentile in height it's unlikely that they're going to be in the NBA in general that's true there is a few exceptions there are late bloomers what we call a constitutional delay of growth but a general rule would be what percent how you are by the age of two or three is pretty much where you're going to track if all things are going normally well I never realized that is that soon and genetics is an important determinant as he said we can actually do a calculation of where we think a child should end up the so-called mid parental height which we are going to talk about later okay so genetics is the critical factor but whether or not you reach your genetic potential means that the cards have to be lined up appropriate right so the cards that are important for achieving your genetic potential first of all number one normal amounts of hormones that are important for growing right and those are thyroid and growth hormone to a large extent right a second factor of course is adequate nutrition and we think worldwide of children who are undernourished who don't look anywhere near their age in terms of height because they're so undernourished it really grabs their style and you see the reverse of that I mean you know as a I know what I'm officially I was born here my parents weren't so I'm like first generation or second generation but you see that in that is that you see a lot of people my generation are much taller than their parents because their parents were probably mounted malnourished in some way certainly there can be a secular trend where the children get taller than the parents if the children have a different environment the other thing we notice about nutrition in our country is the over nutrition of our children and what happens with obesity is that children may grow faster in terms of both weight and height for their age they don't end up taller in the long run but they move ahead more quickly through the maturation process I see I didn't okay well I can accelerate exactly as I did I never realized that that's fascinating and then we think about psychosocial factors there literally is a situation where infants can be deprived of parental love and support and you see some dwarfing there in a teenager we see problems with eating disorders that's a cross between nutrition and a psychological problem so it's like a social factors so that's nice oh so it's if they've shown or it's been seen that it's noticeable changes in physical development based on I guess attention and love and yes there's actually a syndrome called psychosocial dwarfism we actually see a slowdown and growing without adequate that's interpersonal support Wow that's fascinating so the issue is um when do you need to worry I'll write a child's growth pattern right in order to interpret that you have to understand about the variability in growth in the first two to three years of life children grow much more quickly than they will later on by the age of three until they hit puberty children should grow two inches a year two inches a year this is from the ages of two after they're out of toddlerhood until they hit puberty Wow so this is like three to puberty exactly okay exactly but when kids will hit puberty is going to be variable right and so that's an issue if the children are growing at a normal rate it's not necessary to memorize the inches per year children will track along the growth curve and if we can turn to the next slide or next graph well this is a graph for what we use for older children after the age of two up until they're 18 yeah this is the curve that we use now beyond the age of two I said to you it's not normal for children to necessarily cross percent house so if for example you have a child who is tracking along the 5th percentile every year growing they're 2 inches this is the 5th rider over line they're moving along steadily steadily steadily right that child has a more reassuring growth curve than 1 for example who as a 5 year old had been at the top of the curve alright a 5 year old so 5 year olds right there and then the next year is on the 75th moving down a line I see and the year after is on the 50th percentile right now at that point in time the child has theoretically a normal height because it's within the curve but there's something very abnormal about that rate of growth that's the child that's more worrisome interested in the shorter child fascinating so bottom line when a child would come in to present to me because of a concern about growing I first of all try to decide if they're short and if they're growing normally and are two different questions the first question is are they short and are they short can be defined by looking at these curves these are curves representing the spectrum of normal height for healthy American youth and they go from the fifth to the 95th percentile so you can compare a child to the population as a whole but I also like to calculate what we call the mid parental height yep okay this is where we take into account the heights of the parents yeah because that's the most important determinant so how we calculate that is as follows we take the height of mom and dad and average them okay let's do that so I'm five nine right shoes okay so let's start doing it 69 inches okay and how tall is the mother she's five five six she's five six that's why I don't let her wear two large wheels and are we trying to calculate your son or your daughter I let's do my son since he's a little older so let's use about sixty six inches okay so we'll take the midpoint of that okay so that's really inch and a half right image so it's what sixty seven and a half inches between me and my wife right and we're gonna add two and a half inches okay so that gets us what to exactly 70 inches right and that's the height prediction for your son oh very good plus or minus Oh plus or minus more inches plus or minus four inches so that's a big difference it's a big difference yes but that's the nature of human variability I see okay now if this were your daughter mm-hmm we would take the sixty seven and a half inches and subtract two and a half inches let's do that okay she gets our 65 right by five exactly plus or minus four inches plus our foot minus four inches so that's something we do we then calculate um in fact let's plot that right on the curve this is a boy's curve so let's plot the seventy inches seven inches is right over here okay okay and then the range of 74 74 into 66 right exactly pretty broad range yes but if we had a child who was growing well below the curve and we thought that midpoint should be about the fiftieth percentile that child would be short for the family so we always like to take the family heights into account I said number one question is the child short it will depend on what the height prediction is I see so if my son was tracking down here at the 5% concern even if he's growing the two inches every year he's tracking that it still would be concerning well it would raise some questions in our mind right but the more important factor is not just where they are in the curve at the moment but are they growing at the normal rate and the child who is not growing at the normal rate raises more red flags than the child who's trotting up the curve fascinating it's interesting well so that's the issue and that's what we approach every day we want to look into the various causes potentially for growth slowdown we want to address treatment to the specific etiology and an ideology means well for example if the child has a deficiency of thyroid hormone we want to give thyroid hormone if the child isn't growing because he has a nutritional problem like celiac disease we want to put him on a special diet to address that issue some parents think well what we want to do my child is healthy and normal and growing normally but I want to give him some growth hormone that becomes a topic in its right right very good well thank you for this is a super informative