There was an article in the New Yorker (Nov 19, 2007) that had some disturbing news. For almost 20 years, scientists have been debating the "Barker Hypothesis" which found a strong association between low birthweight and increased risk of adult diseases like coronary heart failure, hypertension, type 2 diabetes, and strokes. Although initially dismissed as heretical, these findings have been repeatedly confirmed in recent epidemiological studies. The causal mechanism behind this finding appears to be a complex dialogue between fetus and mother's body---in which the fetus or even embryo adapts itself to the nutrient levels in the maternal environment. In cases where the nutrient levels are less than ideal, the fetus adapts by slowing its growth and thereby lowering its ultimate birthweight. Ironically, such infants later find the more plentiful nutrition of the postnatal environment a stressor rather than an aid to growth. Most at a disadvantage are those children who are born with low birthweight, but gain rapidly in BMI after two years of age.
This last conclusion has serious implications for parents of low birthweight babies (two thirds of whom are premature in the US). If it is dangerous for premature babies to grow too big, too fast, after age two, shouldn't we be more interested in these kids maintaining their percentile position rather than trying to jump up into higher percentiles. Are pediatricians aware of these studies and advocating against rapid weight gains between 2-5 years of age?
What does your pediatrician say? Please let us know...
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- Prof Kim Gutschow
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7 comments:
Huh. At 3, S is 60th% for weight and 30th for height (having been born at 25w3d, 1#13), but nobody's concerned. We haven't actively tried to fatten her up (she's been on the charts for her actual age since she was 9 months old) but she's definitely a good eater and a bit of a tank.
The possible problem with advocating lower weight gain is that it might compromise brain growth, and brain growth is related to later cognitive ability and psychiatric stability.
At Hot Topics, what to do about catch-up growth has been a "hot topic" for years, and the advice keeps changing. Right now, docs are advocating that we go for growth.
BTW, the same group of British adults born after 1946 that was analyzed for the diabetes, metabolic disorder, etc., study has also been analyzed for mental health.
Low birth weight was also correlated in a dose related way to depression in adulthood -- in other words, the smaller the baby, the greater the chance of depressive disorder.
It isn't known how many of these babies were born prematurely, but more recent studies of prematurely-born children are showing the same tendencies to higher blood pressure, endothelial dysfunction, and psychiatric problems that the British studies on low birth weight individuals (some of whom were probably born at full term but suffered from intrauterine growth retardation.)
However, virtually every baby who is discharged from the NICU is growth retarded, at least for a while, during what would have been a critical period of intrauterine development because of the difficulties nourishing preemies artificially.
My son's doctor is not concerned about his weight. He (28 weeker that is now 21 months old) has always stayed on his own curve; I don't think his doctor wants / cares if he "catches" up with his actual age chart.
My son at 1 year old was diagnosed with hypertension. The doctors can't identify an underlying cause - except being premature.
Interesting.
Thanks Helen for that information. It is important to point out that most NICU babies will have some growth depression---and that this is caused not necessarily in utero but ex utero in the NICU. We can stop blaming the moms for this one!
The Hall study mentioned the tendency towards depression and I was thinking of so many children who are born in difficult periods--wars, refugee situations, etc---who might be low birthweight and later have tendency towards depression. How to separate nature/nurture here? In other words how to tell if this is a biological artifact driven by the fetal environment or by the difficult surroundings the child may be born into as well as possible parental depression?
One could also ask the same question of preemies---how might one relate mild depression and other disorders to parental PTSD as well as to the growth retardation of the NICU?
Sarah---I looked at your blog about your daughter and was fascinated last Sept. about your daughter's toddler nightmares. My 26 week twins have been having night terrors. They wake up screaming uncontrollably. Unusually, I cannot soothe them for a good 15-30 minutes---I can't recall when this last happened, probably 2 years or more ago. They are now 3.5 and I wonder if this is a developmental issue, sensory issue, or how common among preemies. I may do a post on this.
Update on the twins night terrors. It was a passing phase, as so much of childhood is, perhaps related to the stress of a year's sabbatical in India, where we moved no less than 7 times in a 5 month. Or maybe they would have had them at this age regardless of the sabbatical.
I catch myself searching for the "why" of a lot of what my twins do before I realize how futile this can be. I think the best thing to do as a parent is empathize, try to help, but not over-rationalize every incident at the risk of blaming oneself or one's situation too much.
Our ped never worried about our 14 1/2 lb 1 year old. Since DD started at 1 ob 14 oz, that was actually a pretty good weight gain in 1 year. She was also not woried by our 21 1/2 lb 2 year old. The ped always told us that as long as DD gained on her own scale, was healthy and on track develomentally, the actual scale reading meant little.
Paula
You have really great taste on catch article titles, even when you are not interested in this topic you push to read it
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