Infants born to mothers who are overweight or obese grow more slowly than those born to mothers of normal weight, according to the results of a study published online on July 23, 2012, in the Journal of Pediatrics. The study included 97 nondiabetic mothers with healthy newborns who completed study visits 2 weeks and 3 months after the infants were born.
Of the participating mothers, 59 were normal weight before getting pregnant, 18 were overweight, and 20 were obese. The researchers found that when the infants were 2 weeks old, those born to overweight and obese mothers had gained less weight than those born to normal-weight mothers, but the difference was only significant for infants born to overweight mothers. By 3 months of age, however, infants born to overweight or obese mothers had, on average, grown nearly a half inch less and gained 11 oz less total weight, including 0.3 oz less fat mass than infants born to normal-weight mothers. All of these results were statistically significant, and the latter is particularly notable as fat mass in infants is thought to be crucial to brain growth and development.
The researchers note that possible explanations for their findings include the effect of inflammation that occurs during pregnancies of overweight and obese women and the underdevelopment of pituitary glands in infants born to overweight and obese mothers. They also note that further studies are needed to test their findings.