The proper diet for pregnancy has always been an interesting debate. In general rich in all nutrients is prefered. For some women this may mean high protein and others this may mean high complex carbohydrates.
But one thing is known for sure, diets high in sugar and simple carbohydrates are not well suited for pregnant women. But what about the baby?
It is true that the only source of fuel for a growing baby is glucose. It is the energy component that passes across the placenta and drives the development of the unborn child. In some pregnancies this child may cause a condition in the mother because of its need and want of glucose.
Gestational diabetes is a condition caused solely by pregnancy. A hormone produced by the developing baby causes changes to the mother's normal glucose metabolism. This change can overwhelm to mother's system and the result is hyperglycemia and glucose intolerance in the mother and a big, happy baby in the womb.
Babies born to mother's with gestational diabetes are often large for gestational age (LGA), or over 9 pounds. They may also have an increased risk for shoulder dystocia, birth injury, and cesarean delivery. The condition can also haunt them into adulthood with increased risk of obesity and adult onset diabetes.
Based on this, one would find it reasonable to believe that glycemic index could be important during pregnancy. Diabetics are counseled to consume a diet with a low glycemic index to prevent high and difficult to manage blood sugars, so why not pregnant women?
To measure if a diets glycemic index value had any effect on pregnancy outcome researchers in Australia enrolled pregnant women and randomized them to either a low glycemic index diet or a moderate to high glycemic index diet.
Each woman was assessed five times during the pregnancy from about the beginning of the second trimester thru delivery. The primary outcomes included newborns weight at delivery, birth percentile, ponderal index, and incidence of LGA babies.
A total of 32 women completed the low glycemic index diet and 30 women the moderate to high glycemic index diet.
Women who consumed a low glyemic index diet had smaller babies on average, with the mean weight difference being 236 grams. Babies born to mothers in the low glycemic group were about 48th percentile compared to 69th percentile for weight. Only 3.3 percent of babies born to mothers in the low glycemic index group were LGA, whereas 33.3 percent in the moderate to high glycemic index group were large for gestational age.
The authors concluded that dietary glycemic index does have a significant effect on pregnancy outcome when assessing newborn weight variables. How this affects the long term health of the newborn is only speculative, but based on other studies babies born in higher percentiles are at increased risk for chronic disease including diabetes and heart disease.
Posted by Dr. Christina Gutierrez on November 14, 2006 09:41 PM
