If you believe that gaining a little weight above what’s recommended while pregnant doesn’t matter, it may be time to re-think that notion. Janet Currie, PhD, of Columbia University and I collaborated to examine this question, and found that excess pregnancy weight gain is a strong predictor of high birth weight in infants. What’s the big deal if a baby is a bit too heavy? Research suggests high birth weight increases risk for numerous health problems, including obesity later in life.

Nearly one-third of children in America are now overweight or obese. Without marked decreases in prevalence, this generation of children may lead shorter, less healthful lives than their parents due to weight related diseases. Because conventional methods to combat the obesity epidemic have had limited success, novel approaches aiming to decrease lifetime risk are greatly needed.

In our study, published online today in The Lancet, we examined all known births in the states of Michigan and New Jersey from 1989 to 2003, focusing on the 513,501 women with multiple births. On average, the women gained about 30 pounds. However, in 12 percent of the pregnancies, women gained more than 44 pounds. Recently updated guidelines from the Institute of Medicine suggest that women gain 25 to 35 pounds if they are normal weight at the beginning of pregnancy, 15 to 25 pounds if overweight, and 11 to 20 pounds if obese.

We found that women who gain excessive weight during pregnancy tend to give birth to heavier infants. For example, women gaining 44 to 49 pounds were 1.7 times more likely to have a high birth weight baby than those gaining just 18 to 22 pounds. Women who gained more than 53 pounds were 2.3 times more likely to do so. Because our study involved comparisons of infants born to the same mother, we can be confident that this effect is not due to genetics.

These findings suggest that the ideal time to begin obesity prevention efforts is before birth, and that the type and amount of food a woman eats during pregnancy may have lasting consequences for her offspring. While much remains to be learned about optimal nutrition during pregnancy, we recommend a low glycemic load diet: abundant quantities of vegetables, fruits and beans; reduced consumption of concentrated sugar and refined starchy foods; moderate amounts of healthy fats (like olive oil, nuts and avocado); and adequate amounts of protein.
by David Ludwig, MD, PhD

For more great parenting tips and pediatric information please check out Thrive, the pediatric blog of Children's Hospital Boston